SCREENING ELITE GENOTYPES AND IPM OF DEFOLIATORS IN GROUNDNUT

Thesis submitted to the University of Agricultural Sciences, Dharwad

in partial fulfillment of the requirements for the Degree of

Master of Science (Agriculture)

in

Agricultural Entomology

By

RASHMI S. YAMBHATNAL

DEPARTMENT OF AGRICULTURAL ENTOMOLOGY COLLEGE OF AGRICULTURE, DHARWAD

UNIVERSITY OF AGRICULTURAL SCIENCES, DHARWAD – 580 005

JULY, 2010

ADVISORY COMMITTEE

DHARWAD JULY, 2010 (R. K. PATIL) CHAIRMAN

Approved by :

Chairman :

Members : 1.

2.

3.

(P. V. KENCHANAGOUDAR)

(B. T. NINGANUR)

(R. A. BALIKAI)

(R. K. PATIL)

CONTENTS

Sl. No. Chapter Particulars

CERTIFICATE

ACKNOWLEDGEMENT

LIST OF TABLES

LIST OF FIGURES

LIST OF PLATES

LIST OF APPENDIX

1. INTRODUCTION

2. REVIEW OF LITERATURE

2.1 Screening of groundnut genotypes

2.2 Different components of IPM for S.litura

3. MATERIAL AND METHODS

3.1 Field Screening

3.2 IPM modules for Northern transitional zone of Karnataka

4. EXPERIMENTAL RESULTS

4.1 Field screening of groundnut genotypes

4.2 Evaluation of IPM modules in groundnut

5. DISCUSSION

5.1 Field screening

5.2 Evaluation of IPM modules in groundnut

6. SUMMARY AND CONCLUSIONS

REFERENCES

LIST OF TABLES

Table No.

Title

1. Performance of elite groundnut genotypes against Spodoptera litura damage under field condition during Kharif 2009

2. In vitro larval duration (in days) of Spodoptera litura on elite groundnut genotypes

3. Gain in larval weight and larval mortality of Spodoptera litura at different days after hatching on elite groundnut genotypes under laboratory conditions

4. Biological parameters of Spodoptera litura on elite groundnut genotypes under laboratory conditions

5. In vitro biology of Spodoptera litura on elite groundnut genotypes

6. Thrips population in different IPM modules of groundnut

7. Leaf hoppers population in different IPM modules of groundnut

8. Thysanoplusia orichalcea population in different IPM modules of groundnut

9. Spodoptera litura population in different IPM modules of groundnut

10. Spilarctia obliqua population in different IPM modules of groundnut

11. Aproraema modicella population in different IPM modules of groundnut

12. 12: Per cent defoliation by defoliators at 35, 50 and 65 days after sowing in different IPM modules

13. The management of Spodoptera litura in IPM modules of groundnut during Kharif 2009

14. Incidence of sucking and defoliating insect pests on sunflower (Trap crop)

15. Incidence of defoliators on main and trap crop

16. Natural enemy population in different IPM modules of groundnut (Coccinellids)

17. Natural enemy population in different IPM modules of groundnut (Syrphids)

18. Natural enemy population in different IPM modules of groundnut (Campoletis chloridae)

19. Economics of IPM modules during Kharif 2009

LIST OF FIGURES

Figure No.

Title

1. Performance of elite groundnut genotypes for Spodoptera litura damage during kharif 2009

2. In vitro biology of Spodoptera litura on elite groundnut genotypes

3. Gain in larval weight and larval mortality of Spodoptera litura at different days after hatching on elite groundnut genotypes

4. Incidence of defoliators on main and trap crop

5. Pest and natural enemy population in different IPM modules of groundnut

6. Economics of IPM modules during kharif, 2009

LIST OF PLATES

Plate No.

Title

1. Resistant and susceptible genotypes of groundnut

2. IPM modules take up in groundnut

LIST OF APPENDIX

Appendix No.

Title

I. Pheromone trap catches of Spodoptera litura

1. INTRODUCTION

The cultivated groundnut (Arachis hypogaea L.) is an important oilseed crop of tropical and subtropical areas of the world. In India, the crop occupies an area of 5.7 million hector with a production of 4.7 million metric tons with an average productivity of 0.8 metric tons per hectare during rainy season (Radhamani and Singh, 2008). Among major groundnut producing states of India, Karnataka ranks fourth in acreage (0.76 m ha) with total production of 0.38 million tons (Anon., 2009). More than 50 insects have been reported to occur on groundnut in India and few are quite destructive and reduce the yield considerably. Aproaerema modicella Deventer, Amasacta albistriga Walker, Spodoptera litura Fabricus, Helicoverpa armigera Hubner, Aphis craccivora Koch, Frankliniella schultzeri Trybom, Thrips palmi Karny and Scirtothrips dorsalis Hood are considered as important destructive pests on groundnut (Amin and Mohammad, 1980).

The tobacco caterpillar, S. litura is widely distributed throughout the world. It is a polyphagous pest and reported on more than 120 host plants. It is next to H. armigera in terms of economic importance at national level. The population of this defoliator in groundnut ecosystem has been found to increase in number and intensity both in rainy and post rainy seasons, especially in fields where insecticides have been applied (Rao and Shanower, 1989; Stechmann and Semisi, 1984) due to destruction of natural control system. In recent years, these pests created a serious threat to agricultural industry due to development of resistance towards commonly used insecticides. Populations of many pests including S. litura have developed resistance to many commercially available pesticides (Ramakrishnan et al., 1984 and Rame Gowda, 1999).

Spanish bunch type cultivars are the most popular cultivars in the northern transitional zone of Karnataka as they mature early and facilitate double cropping. But, all presently cultivated varieties are susceptible to S. litura. Scientists have been successful in developing some cultivars utilizing resistant sources. Hence systematic evaluation of these genotypes developed at the AICRP on oilseeds, UAS, Dharwad center was taken to find out nature of resistance in the present investigations.

Mechanisms of resistance are under genetic and environmental control. The resistant cultivar helps in suppressing the pest population and act as a principal control method. The genotypes with different mechanisms of resistance could be hybridized to pool the genes to enhance the level and effectiveness of resistance. Enhanced resistance is desirable in managing the pest especially when there is heavy pest load or an early outbreak, due to continuous cropping system. The knowledge on mechanisms of resistance or avoidance is also helpful in designing appropriate strategies in screening for resistance to the pest.

Hence, entomologist and environmentalist felt to develop viable alternate strategies which could be integrated into a workable system called integrated pest management that could reduce negative influence of chemical pesticides on the environment by utilizing ecofriendly components such as bio-pesticides, cultural practices, semiochemicals and many other harmonious practices. Therefore, a unilateral approach of controlling crop pests by synthetic insecticides has dictated the necessity for need based, cost effective, eco-friendly and safe pest control strategies.

In recent years the problem of resistance to chemical has worsened, resulting in 20-30 per cent crop loss due to pests in India (Bhargava et al., 2008) and causing widespread hardship especially amongst poor farmers. In addition to the development of resistance in pests, indiscriminate and injudicious use of pesticides has grossly poisoned almost each component of the biosphere, caused resurgence of pests and reduction of natural enemies in agroecosystems allowing rapid rebund of target and minor pests. The development of a broad-spectrum resistance to insecticides has complicated its chemical control. It is therefore imperative that an integrated pest management strategy should be devised for managing this pest.

In some parts of the northern Karnataka, farmers are experiencing difficulty in managing the pests on groundnut and other crops. Groundnut is largely a smallholder crop grown under rainfed with low inputs. The low yields in groundnut are primarily due to low inputs, rainfed cultivation, non availability of seeds of suitable high yielding variety and the occurrence of insect pests and diseases at different stages of the crop and also due to extreme climatic conditions.

Millets are cultivated as rain-fed crops, which require less crop management practices, there is less preference shown by farmers for cultivating these crops. Whilst a number of traditional foods are made in the domestic household, the lack of large-scale industrial utilization discourages the farmers raising these crops.

Integration of biological agents, mixed and intercropping, pheromone traps and resistant varieties appear to be ideal strategies against S. litura on groundnut crop. With this background in mind field and laboratory trials were undertaken during the year 2009 kharif season at the Main Agricultural Research Station, University of Agricultural Sciences, Dharwad. Following are objectives related to the above study.

1. Screening of elite groundnut genotype under field condition and to study the biology of S. litura on elite genotypes of groundnut under laboratory condition.

2. To evaluate IPM modules for northern transitional zone of Karnataka.

2. REVIEW OF LITERATURE

The review of literature pertaining to biology and integrated pest management of Spodoptera litura on groundnut are presented in the following paragraphs.

2.1 Screening of groundnut genotypes

Moss (1980) reiterated that research done on the utilization of wild species of Arachis in U.K. has been of immense help in the ICRISAT programme. Fifty cultivated genotypes were screened for resistance to defoliators in the AICRP on groundnut at Dharwad during kharif 1985.Among them 40 entries recorded injury rating 3 while 7 entries were under rating 2(Anon., 1985).

Further, GBPRS-312 and ICG-5240 were found to be resistant to S.litura in the laboratory trails at ICRISAT, Hyderabad (Anon., 1995). The cultivated groundnut genotypes such as ICG-7948, 8081, 8232, 8781, 8977, 9012, 9039, 9449 and 9961 were grouped as promising by Kulkarni, (1989). Dark green leaves and rough texture were associated with resistance, while light green and smooth texture with susceptibility.

During kharif 1995-97 at Jalgaon, Maharashtra, India, S. litura larval damage to foliage was recorded in 32 genotypes. The lowest leaf damage (5%) was recorded in ICGV 86156, ICGV 86400, ICGV 86528, ICGV 87128, ICGV 87141, ICGV 87290, ICGV 87411 and ICGV 91214 (Dharne and Patel, 2000). Fifty groundnut genotypes were screened for resistance to S.litura in All India Co-ordinated Research Project on Oil Seeds at Dharwad (Anon., 1985). Due to low level of infestation during kharif 1985, majority of entries (40) fell under injury rating of 3. However, 7 entries were under injury rating of 2 and three entries sustained higher damage with a rating of 4. At Hissar, GC-79 and GC-333 were observed to be from S. litura damage (Anon., 1985). Of the 50 cultivated groundnut genotypes screened for resistance to defoliator, 22 entries fell below injury rating scale of 2, thirteen below rating 3, three below rating 4,six below rating 5 and one below rating 6 (Anon., 1986).

Fifteen A. hypogaea genotypes were screened in laboratory using choice test for resistance to H. armigera (3

rd instar) and S. litura (1

st, 3rd and 5

th instar). Of them, only BG2 a

Virginia bunch variety was resistant to both the pests (Singh et al. 1993). Based on oviposition and feeding performance test conducted with the seven cultivars, NC Ac 343 was least preferred, while the UPL Pn 2 was the most preferred and EG Pn 13 occupied an intermediate position (Xie Jia Li, 1987). The cultivar C-501 was most resistant and M-145 was the most susceptible among the nine groundnut varieties tested in laboratory at Pantnagar on the basis of growth and development of S. litura (Tiwari et al. 1989).

Preliminary screening to assess the resistance to S. litura was carried out in the field on six Virginia bunch and 18 Virginia runner accessions and higher resistance was recorded by Virginia runner varieties NC Ac 17840, NFG 79 and EC 21989 (Rajgopal et al. 1988). In screening study by Patil et al. (1991), entries ICGV 87264 and 86598 have recorded the least damage (< 17.5%) and entries ICGV 86598 and 86125 have also recorded less damage (<27.5%). Other entries, ICGV 86350, 86276 and 87287 showed promise for resistance with least damage (17.5%) at two stages of screening (75 and 90 DAS). RG 97 was another promising line resistant to S. litura.

Bioassay carried out with larvae to understand the mechanism of resistance by Wightman and Ranga Rao (1994) revealed no antibiosis effect on 2

nd and 4

th instar larvae

when fed to matured leaves of ICGV- 86031.According to them the resistance factor that influences the neonates is associated with the leaf surface, because of which their feeding activity is restricted only to the scraping on the leaf surface. Dwivedi et al. (1993) identified ICGV-86031 as multiple resistant variety against thrips, jassids, S. litura and groundnut leaf miner.

Groundnut genotypes DER (Dharwad Early Runner) treated with ethyl methane sulfonate, yielded many Valencia mutants with multiple resistance to foliar diseases. These

mutants were systematically screened for S. litura in 1996. Based on leaf area damage, three mutants (28-2, 45 and 110) were identified as resistant to S. litura (Prasad et al., 1998).

Screening of groundnut germplasm and advanced breeding lines in the All India Co- ordinate Project has resulted in new sources of resistance to S. litura with better agronomic background –ICGV 86364, 91172, 86400, 86402, 91112, M 335 (Anon., 1998). ICGVs 86364, 86590, 91167, ICGS 44 and ICG 22719 (Anon., 1999). Several years of screening germplasm collections at National Research Center for Groundnut, Junagadh resulted in genotypes viz., NRCG 5724, 2615, 9773, 8313 and 8673 possessing resistance/ tolerance to S. litura (Basu, 2003).

2.1.1 Biology of Spodoptera litura

2.1.1.1 Biology of Spodoptera litura on different hosts

Balasubramanian et al. (1984) reported the effect of castor (Ricinus communis L.), tomato (Lycopersicon esculentum Mill.), sweet potato (Ipomoea batatas L.), okara (Abalmuschus esculentus L.), cotton (Gossypium sp.), sunflower (Helianthus annus L.), Lucerne (Medicago sativa L.) and egg plant (Solanum melongena L.) on the biological aspects of S. litura. The incubation period was shortest on castor (3.5 days) and longest on okra (5.0 day). The duration of larval, pre-pupal and pupal periods were less and the larval length, pupal weight and length, percentage of pupation and adult emergence were high on castor. Moths reared on castor had shorter developmental period, high growth index, low pre-oviposition period, extended oviposition period and high fecundity. Similar trend was reported by Garad et al. (1984). Parasuraman and Jayaraj (1985) found castor as ideal host with shorter life cycle, maximum growth index and high fecundity, groundnut was intermediate. Maize and horsegram affected biology, growth index and fecundity.

Bhalani (1989) studied growth and development of S. litura on seven natural food plants in the laboratory. On the basis of larval survival, growth index, pupal weight, size, duration, emergence and fecundity, castor was the most suitable food plant, while maize was least preferred, resulting in a prolonged larval period and lowest growth index. The suitability of the remaining plants was as follows cotton> groundnut > cowpea> green gram >sorghum.

Kulkarni (1989) reported the effect of castor, soybean, mulberry, two cultivated groundnut varieties and two wild groundnut varieties on the biological aspects of S. litura. Among the all hosts, castor proved to be most suitable as it favored optimum growth and development of the insect. The larval period was 16.5 days on castor as against 20.0 days on cultivated groundnut. The larvae passed through six instars on all the hosts except the wild peanut genotypes. S. litura reared on the castor had shorter life cycle (30.8 days) while groundnut had longer life cycle (37.8 days). The fecundity was maximum on castor (635), minimum on mulberry (450) and intermediate on groundnut (585).

The influence of three host plants viz., castor, sunflower and groundnut on the organic constituents and the fecundity of S. litura was studied in the laboratory. The organic constituents of the leaves significantly influence the larvae. Females resulting from larvae on castor laid 1038 ± 116 eggs while those from sunflower and groundnut 684 ± 53 and 878 ± 73 eggs, respectively. The protein and nitrogen contents of the leaves of castor were higher than those of the other two host plants and this was responsible for the higher fecundity on castor (Sankarperumal et al., 1989).

Bae-SoonDo (1999) conducted study to determine the larval development of tobacco cutworm, S. litura on leaves of 11 different leguminous plants, varieties and cultivars, and to measure the amount of leaves fed by the larvae. Larval duration ranged from 11.5 to 15.7 days depending on the different food sources with the shortest on soybean cv. Geomjeongkong-1 and the longest on groundnut cv. Daekwangddangkong. Among the 6 larval development stages, the 1

st instar was the longest (3.2-5.0 days) while the 4th instar

was the shortest (1.0-1.5 days). In general the amount of leaves consumed was increased with larval age. Consumption of the total food (55 to 74%) was only during the last instar

stage, with the female consuming more food than the male. Larval mortality and the sex ratio seem to have no relation with the amount of food consumed per species.

According to Ghumare and Mukheijee (2003) the five host plants [castor (Ricinus communis L.), cotton (Gossypium hirsutm L.), tomato (Lycopersicum esculentum M.) mint (Mentha arvensis L.) and cabbage (Brassica oleracea L.)] belonging to different families were used to study the performance of the Asian armyworm, S. litura. Highest consumption of food and dry weight gain was observed in larvae fed on castor. Mint did not support optimum larval growth because of low digestibility and low efficiency of conversion of digested food to body matter. Dry weight gain ranged from 26.64 mg on mint to 86.80 mg in castor.

The biological parameters of S. litura were studied on cotton and different weed plants viz., itsit (Trianthema portulacastrum), tandla (Digera arvensis) and thakra (Tribulus terrestris) under laboratory conditions at Entomology Research Farm and Laboratories of the Department of Entomology at Punjab Agricultural University, Ludhiana during 2006 Kharif season. The study suggests that S. litura showed faster larval development on all three weeds as compared to cotton, although the larval and pupal survival was lower on these weeds. These results suggest that the role of weeds in the development of S. litura cannot be overlooked (Inderjit et al., 2006).

Dara and Prasad (2007) estimated the population parameters of S. litura on green gram (Vigna radiate L.), black gram (Vigna mungo L.), groundnut (A. hypogaea) and chilli (Capsicum annuum L.) along with castor bean as control in the laboratory. Field-collected egg masses of S. litura were used to start the initial colonies. S. litura population showed a positive trend on all host plants. The population parameters net reproductive rate, intrinsic and finite rates of increase, weekly multiplication rate, and potential fecundity were highest on castor bean, followed by greengram, blackgram, groundnut and chilli. Accordingly, the mean generation time and doubling time were shortest on castor bean, followed by greengram, blackgram, groundnut and chilli. Stable age-distribution showed that egg, larvae and pupae contributed to > 99 per cent of the population stable age.

Maghodia and Koshiya (2008) studied that the life history of S. litura at 27.10C in the

laboratory on five different crops presumably observed as host plants of S. litura. The data were analyzed based on age-stages and variability of developmental rate among individuals of the pest. The highest intrinsic rate of increase (r), the finite rate of increase and the net reproduction rate (Ro) of S. litura were 0.174, 1.192 females/day, 1370.74 offspring/individual, respectively, observed on castor, while the highest mean generation time (T) 45.48 days was observed on cotton. The life expectancy of newly deposited eggs was 17.34, 17.44, 16.39, 17.45 and 17.98 on castor, tobacco, groundnut, cotton and cabbage, respectively. The age specific fecundity of S. litura was 395.64, 179.32, 186.25, 292.64 and 25.14 progenies per day on the 42

nd, 44

th, 41

st, 46

th and 51

st days for castor, tobacco, groundnut, cotton and

cabbage, respectively. Studies on age-specific distribution of the pest on different hosts revealed that the eggs and larvae contributed the highest to the population, whereas the contribution of the pupae and adults was negligible.

2.1.1.2 Biology of Spodoptera litura on different varieties of groundnut

Host plant resistance can be exploited as an effective and environment friendly component of pest management. At present, S. litura is a prominent defoliator associated with groundnut crop. So incorporation of resistance to this in suitable varieties has been high priority for groundnut breeders in association with entomologists.

Tiwari et al. (1980) studied on the survival and weight gain in larvae of S. litura reared on 9 varieties of groundnut. Four days after feeding, larval survival was similar on all varieties except C-501, where high mortality rate was recorded. This trend was also observed 8 days after feeding, but after 12 days the mortality rate did not change. Larvae feeding on C-501 weighed 1.26 mg after 4 days, while on Dwarf Mutant larval weight was 4.41 mg. Larval weight after 8 days' feeding was significantly greater on Dwarf Mutant than on the other varieties, and was lowest on C-501. After 12 days of feeding, the greatest weight gain was

observed on Dwarf Mutant, the lowest gains were observed in larvae on AH-1192, OG-71-3, JH-62, M-13 and C-501, and moderate gains were observed on J-11, Pol-2 and M-145.

Intrinsic rates of increase of S. litura on 9 different varieties of groundnut were assessed in Andhra Pradesh, India. Life-tables were prepared from the results of observations on the development of larvae and on the number and viability of eggs produced by the ensuing adults, the intrinsic daily, weekly and monthly rates of increase being calculated. The duration of a generation was shorter and the intrinsic rate of increase was higher on the varieties, Dwarf Mutant and Pol 2 than on any of the others. Since this indicates a very rapid buildup of populations of S. litura on these 2 varieties, it is recommended that they should not be cultivated in areas where this pest is a common problem on other field crops. Larval mortality was highest on ICGV 86031 (82.8%) followed by ICGV 86350 (53.32%) and Dh-3-30 (43.02%). Development was shortest on Dh-3-30 (32.25 days), and longest on ICGV 86031 (37.5 days) with adults surviving a maximum of 9.5 days. Of the nine groundnut varieties tested in the laboratory for resistance to S. litura, C-501 was most resistant and M -145 was the most susceptible (Tiwari et al., 1989).

The biology of S. litura was studied on different groundnut genotypes along with wild tetraploid, Arachis manticola (L.) (Kulkarni, 1989 and Patil et al., 1995). Survival was least on the wild species, while it was maximum on Dh-3-30. The Survivability on ICGV-86031, 87264 was comparatively low followed by ICGV-86165, 86350, 86699 and GBFDS- 272. The larval duration was short while gain in larval weight and survival percentage were high on susceptible genotypes indicating higher rate of multiplication. On the other hand, these parameters were reversed in resistant genotypes. In laboratory feeding bioassay by Todd et al. (1991), it was found that larval weight (75.7) mg was more in susceptible variety (Southern runner) as compared to resistant genotypes (26.5 mg). Larvae fed on florunner required an average of 3.7 more days to develop, compared to larvae fed on curly leaf. Similarly, Singh and Sachan (1992) identified ICGV-86030, 86031 and NCAC 343 as resistant to S. litura based on survival, weight gain and larval duration.

Patil et al. (1991) reported that the performance of 27 and 15 entries in initial and advanced groundnut varietal trials, respectively, for defoliator damage at75 and 90 days after sowing, and productivity during the 1989 rainy season at Dharwad. Entries ICGV-87264, ICGV-86598 (Advanced varietal trial), ICGV-86350 and ICGV-86276 (Initial varietal trial), which combined low leaf damage (<17.5%) and high pod yield (2039-2320 kg/ha), were recommended as sources of resistance in future breeding programmes. During kharif season at Jalgaon, Maharashtra, India, S. litura larval damage to foliage was recorded in 32 genotypes. The lowest leaf damage (5%) was recorded in ICGV 86156, ICGV 86400, ICGV 86528, ICGV 87128, ICGV 87141, ICGV 87290, ICGV 87411 and ICGV 91214 (Dharne and Patel, 2000).

Tiwari et al. (1981) reported that the groundnut variety C-501 was less suitable as food plant to S. litura, possibly on account of the texture of leaves and or the presence of a growth regulator. Stevenson et al. (1993) evaluated fourteen wild species of Arachis in laboratory and field to know their effect on the survival and development of larvae. All the species studied were resistant compared to the susceptible control (TMV-2). Over all, the mortality and development of neonate larvae to excised leaves of different wild genotypes was more than 94 per cent vis-à-vis less than 20 per cent on TMV-2. Third instar larvae lost weight when exposed to both field plants and excised leaves of eight wild species, whereas larvae feeding on TMV-2 gained weight. A penetrometer was used to determine the relative toughness of the leaves. The leaves of most of the wild species were shown to require a greater biting effort for feeding than the leaves and larval development. The physical quality of the leaves and foliar chemicals were implicated as being responsible for the observed resistance.

Life table studies of S. litura on groundnuts were carried out in the laboratory. The net reproductive rate, the innate capacity for increase and the daily finite rate of increase were 20, 2.4, and 1.14, respectively. On reaching the stable age distribution, the population of S. litura would comprise 50.8, 45.97, 2.82 and 0.41% eggs, larvae, pupae and adults, respectively (Kulkarni and Lingappa, 1993)

Sreenivasa et al. (1997) studied on the development of S. litura as influenced by groundnut genotypes. In laboratory studies, larval mortality of S. litura was highest on the groundnut variety ICGV 86031 (82.8%) followed by ICGV 86350 (53.32%) and Dh-3-30 (43.02%). Development was shortest (32.25 days) on Dh-3-30 with adults surviving for a maximum of 10.5 days and longest (37.5 days) development on ICGV 86031 with adults surviving a maximum of 9.50 days. ICGV 86350 was intermediate.

S. litura reared on EMS treated Valencia mutants at Dharwad, Karnataka, showed that mutant 28-2 and 45 consistently showed less leaf damage, high mortality, low weight and low gain in weight of larvae compared to susceptible check (JL-24) and parents (DER and VL 1) at all stages. The mortality and gain weight was very much pronounced on neonate larvae. The resistance effect of these mutants also extended the larval period by three days and had pronounced effect on the fecundity of moths indicating resistance in the mutants (Prasad et al., 2000). Leuk and Skinner (1971) reported that the mean length of the life cycle of Spodoptera frugiperda (S.) was shorter (29 days) for the susceptible Starr than South Eastern runner (33.3 days). The mean percentage of moth emergence was significantly less for larvae fed on foliage of the resistant cultivar, south eastern runner and the mortality of the total insects fed with the foliages was higher at all the stages of larval development and pupation on south eastern runner than starr.

According to Patil et al. (2005) the investigations have been carried out for four years from 1996 to 1999 involving elite genotypes of groundnut to assess the yielding potentiality over different agroclimatological conditions and also understand the mechanism of resistance to major defoliator S. litura. Among the genotypes Dh-53 surpassed all other entries for pod yield under unprotected conditions and hence considered to be a resistant variety of groundnut against S. litura.

In the laboratory condition, rearing of insect on resistant genotypes like NC Ac 343, Mutant 28-2 and R 9227 affected larval growth and survival, pupal development, adult emergence and fecundity indicating antibiosis as the principal mechanism of resistance (Prasad and Gowda, 2006).

Patil et al. (2009) investigated the presence of resistance mechanism in elite genotypes of groundnut against S. litura. Eleven genotypes of groundnut such as TR-1-16-2, R-D-1-51, MN-1-35, DCG-17, M-1-28,R-9227, Dh-4-3, Dh-53, R-2001-2, ICGV-86590 and Dh-3-30 were evaluated. The variation in larval development and pupal weight after feeding on these groundnut varieties were taken as criteria and subjected to analysis. The larvae fed on leaves of MN-1-35, R-9227, DCG-17, M-1-28, Dh-53 & TR-1-16-2 recorded low to moderate larval weight and lower pupal weight. Higher larval and pupal weight was recorded in larvae fed on leaves of ICGV-86590, R-2001-2 and Dh-3-30. The results clearly indicated the presence of resistance mechanism in some groundnut genotypes against the S. litura.

2.2 Different components of IPM for S.litura

2.2.1 Seasonal incidence of S. litura measured by the use of pheromone traps

Sreedhar (1983) monitored the activity of S. litura moths in cabbage fields at two locations in Karnataka using sex pheromone traps and found peak moth catches during last week of February at Raichur and during second week of March at Dharwad. However, Kulkarni (1989) noticed this pest to be active throughout the year at Dharwad. But more moth catch was seen from June to October with peak moth activity during September.

Pawar and Shrivastava (1988) tried pheromone traps baited with lure of S. litura and H. armigera separately and together in a groundnut field in Andhra Pradesh. There was no difference in catches of S. litura in traps with any one of the lures or a combination of both the lures.

Singh and Sachan (1991) recorded seven peaks of S. litura in the sex pheromone traps at Nainital, Uttar Pradesh, during the cropping seasons of 1988-1989 and 1989-1990 of which five peaks were observed during the rainy season and the rest during spring.

Rao et al. (1991) reported that the efficacy of four pheromone trap designs was compared for catching male tobacco caterpillar, S. litura moths in fields. There was no significant difference in the performance of the single and double funnel traps, and the single funnel (20 cm dia) trap captured more moths than any other trap.

According to Lalita and Reddy (1992) the relative efficiency of ICRISAT standard trap and sleeve trap for trapping males of S. litura and H. armigera using synthetic sex pheromone and their rhythm of male attraction has been assessed. ICRISAT standard trap have been found to be more efficient by 1.2 times over sleeve traps in mass trapping of both S. litura and H. armigera particularly on the days with distinct peak for both the pests with a highest moth catch at 2.00 am to 4.00 am followed by 10.00 pm to 12.00 midnight for S. litura and 2.00 pm to 4.00 pm followed by 12.00 midnight to 2.00 am for H. armigera.

Singh and Sachan (1993) recorded four peaks of S. litura of which the first and second were small and caused no threat to groundnut at Nainital. The third was observed at the pegging and pod initiation stage. During the first week of September and coincided with the greatest rate of oviposition on leaves. The fourth peak was greatest and occurred between 40

th and 43

rd standard weeks.

Sreenivasulu et al. (2003) monitoring studies of S. litura on groundnut carried out during rabi 2000 in Tirupati, Andhra Pradesh, India, using synthetic sex pheromone traps indicated that the peak male moth catch was observed during the 2nd week of February while the highest number of egg masses were observed during the 2nd week of February and the highest number of larvae/20 m

2 during the 4th week of February. The moth catches in

pheromone traps were found to be positively correlated with number of egg masses and larval counts of S. litura on groundnut in the field.

Pheromone as a mass trapping tool have also been utilized in a few insects such as Pthorimoaea opercullela (Z.), S. litura, Chilo sacchariphagus indicus (K.), H. armigera, A. modicella, Lymantria obfuscata (W.), Cydia pomonella (L.) and Pectinophora gossypiella (S.) The communication disruption as a tool has been tried in S. litura, A. modicella, Peripleneta americana (L.) and Chilo auricilius (D.) in India with limited success. Attempts were made to design the trap for efficient trapping of the target insect, some of them were successful in the case of cotton, sugarcane and groundnut ecosystem. In oilseeds, seven insects are being included for monitoring, and for mass trapping the groundnut leaf miner (GLM), the tobacco caterpillar (S. litura) were tried. Mating disruption with saturation of sex pheromone was tried in GLM (Nandagopal, 2006).

According to Tojo et al. (2008) traps with sex pheromone (litlure) of S. litura were set at nine locations in five countries in South Eastern Asia to compare the daily patterns of male moths caught in traps during the overlapping two years between 1997 and 1999. When the records for observation periods were averaged, the daily number of males from June to November was low in the locations of the year-round occurrence of males, as 0.4 on Sulawesi Island in Indonesia (5°S), 2 on Luzon Island in the Philippines (15°N), 2 in Chiayi, Taiwan (24°N), 4 in Kwangsi, China (25°N), 11 in Fukien, China (27°N), and 20 in Okinawa, Japan (26°N), whereas in locations where essentially no males were caught during winter, significantly more males were caught daily as follows: 108 in Chekiang, China (30°N), 192 in Kagoshima, Japan (31.5°N) and 47 in Saga, Japan (33.5°N). This increasing tendency of males toward northern latitudes suggested the northward migration of this species, and further to Kyushu from China, distributed at the same and/or lower latitude, if they could migrate overseas.

2.2.2 Intercrops/ trap crops in groundnut to mange insect pests

Intercropping has been an important component of small farm agriculture (Lamb, 1978) and one of the reasons for the evolution of these cropping patterns may be the reduced

incidence of insect pests (Altieri et al., 1978). Kennedy and Raveendran (1989) reported that groundnut intercropped with pearl millet reduced the incidence of sucking pests substantially.

Gavarra and Raros (1975) found more predatory spiders and predatory coccinellids in groundnut-maize cropping system than in sole crop of groundnut. The incidence of leaf hoppers, thrips and aphids were significantly reduced and population of predatory coccinellids was increased, when pearl millet intercropped with groundnut (Kennedy et al., 1990).

Singh et al. (1991) conducted the field experiments in Delhi, in kharif season of 1987-88, groundnut intercropped with red gram, green gram, sorghum and soybean. Among these intercrops, groundnut- sorghum intercropping reduced the incidence of leaf hoppers, thrips, bihar hairy caterpillar and tobacco caterpillar.

Agasimani et al. (1993) studies conducted on the incidence of S. litura in the intercropping system indicated the maximum incidence noticed in groundnut + sunflower (4:1) intercropping whereas, the least incidence was noticed in groundnut + jower (4:1) intercropping. Patil (1993) reported among various intercrops, groundnut + sorghum recorded less S. litura damage. Whereas, groundnut + sunflower, groundnut + cotton and groundnut + chilli recorded more damage.

Anonymous (2003) reported that among the two most important defoliators of groundnut, S. litura and H. armigera both prefer sunflower over groundnut for oviposition and feeding. Also, the newly hatched larvae of these pests disperse immediately from the egg site on the groundnut crop, while on the sunflower they stay for a week to ten days on the same leaf. These larvae make skeletons of sunflower leaves. At this stage, the damage on the trap crop (sunflower) is clearly visible, making it easier for the farmers to collect the leaves under attack for subsequent destruction of the larvae, and without chemical pesticides. Since groundnut is more vulnerable to defoliators before the flowering stage, it is necessary to protect this crop from defoliators during this phase. While the larvae feed and develops on the trap crop, the main crop (groundnut) escapes from the critical pest damage.

The influence of straight fertilizers and organic manures on the groundnut sucking insect pests viz., jassid, Empoasca kerri Pruthi and aphid, Aphis craccivora Koch was studied in the field from 1994 to 1996 in sandy loam soils. These studies combined with other cultural practices like planting sunflower as a trap crop for S. litura and spraying of nuclear polyhedrosis virus (NPV) to reduce the incidence of S. litura (Rajasekhara, 2002).

Theodore et al. (2008) reported that groundnut intercropped with maize reduced the incidence of aphids, thrips and pod borers and increased the population of predators and also yield. The higher numbers of predators in groundnut/maize could be due to the crop canopy providing more food and, shade to allow development of their different stages (eggs, larvae).

2.2.3 Natural enemies of Spodoptera litura

According to Battu (1977), field collected larvae of S .litura were parasitized by the tachanid, Parasacrophaga misera (Wlk.) during October –November and by the ichneumonid, Campoletis sp. Both of these were first recorded from India.

Joshi et al. (1979) reported that the natural enemies of S. litura on tobacoo in Andhra Pradesh. They collected eggs and larvae of S. litura from the field and reared in the laboratory for the emergence of parasites like Trichogramma australicum (Girault), Chelonus formosanus (Sonan), Apanteles sp, Strobliomyia aegyptia (Vill.), Blepherella setigera (Corti), Sarcophaga dux (Thoms.) and also predator like Ropalidia sp.

Rao (1983) noticed that eggs of Corcyra cephalonica (Stainton) served as food for the larvae of Chrysopa scelestes (E.). These Chrysopa larvae were highly effective and fed voraciously on Corcyra eggs, Myzus persicae (Sulzer), Bemisia tabacci (Gennadius), eggs and just hatched larvae of S. litura.

Thontadarya and Nangia (1983) reported natural enemies of S. litura infesting soybean at Hebbal, Bangalore. Trichogramma chilonis Ishii, Brachmaria sp. and Bracon brevicornis (Wesmael) parasitized 32.5 per cent of the eggs, 3.4 per cent of the pupae and 16.3 per cent of the larvae, respectively. In addition, a nuclear polyhedrosis virus infected 21.4 per cent of the larvae. The list included Chrysopa sp, Coccinella sp and Scymnus sp preying on eggs or larvae of S. litura .According to the detailed studies conducted at IARI, New Delhi, Telenomus remus Nixon accepted 10 to 72 h old eggs of S. litura.

Kulkarni (1989) recorded larval parasitoids emerged from S. litura in groundnut viz., a braconid, Bracon brevicornis Wesmael, an icneumonid, Campoletis chlorideae Uchidas and two tachinids, Campsilure concinnata Meigen, Peribaea orbatta Wiedemann. The occurrence and abundance of insect pests of groundnut and parasitoids, predators were studied in the field in Bangladesh in1984. 18 species of insect pests were recorded of which, Spilosoma obliqua, S. litura, Thysanoplusia orichalcea (F.) were dominant and one parasitoid, Gryon antestiae (Dodd) (Scelionidae), two predatory species Coccinella septempunctata (L.) and syrphids, Paragus sp. (Islam et al., 1983).

Sridhar and Prasad (1996b) reported that larval parasitoids of S. litura, viz., Peribaea orbatta Wied. and Apanteles ruficrus Haliday caused 13.7 per cent and 8.2 per cent mortality, respectively in groundnut. Srivastava and Kushwaha (1995) reported that the parasitoid complex of S. litura consisted of an egg parasitoid, T. chilonis (31.8%) and nine larval parasitoids of which P. orbatta (14.3%) was the most abundant in cauliflower.

Rao et al. (1990) observed that 5-10 per cent parasitisation of Charops obtusa (M.) and 80 per cent parasitisation of Apanteles africanus Cameron on S. litura in laboratory condition and these parasitoids were highly effective in tobacco nurseries. They also reported A. ruficrus was gregarious polyembryonic parasitoids parasite on S. litura in tobacco field. Similar trend was reported by Braune (1989).

2.2.4 Potentiality of Nomuraea rileyi (Farlow) Samson to Spodoptera litura (F.)

Gopalkrishnan and Mohan (1990) reported that the field trials on N. rileyi against third instar larvae of S. litura on cabbage revealed that the fungus @ 1.2 × 10

8 conidia/ml caused

95 per cent mortality in 6 days after treatment. In the field, larval mortality of 52-60 per cent was observed at 12 days after spraying. The highest cumulative mortality of 88-97 per cent was observed after 19 days (Vimaladevi, 1994).

In the laboratory, spraying the fungus at 108, 10

9, 10

10 and 10

11 conidia per litre of

water against first instar larvae of S. litura resulted in cent per cent mortality within 5 days. The LC50 for third instar larvae was 2.89 × 10

10 at eight days. In the net house studies, initial

mortality was observed at 7-8, days with an LC50 of 2.2×1010

spores per litre. Larval mortality was initially observed in the field at nine days after spraying with the conidia. Even the lowest dose of 2 × 10

11 spores per litre resulted in significant cumulative larval mortality. There was

no increase in mortality with increased dose (Vimaladevi, 1994).The conidial suspension sprayed on egg mass was found to cause 95.2 per cent mortality of neonate larvae (Gopalkrishnan and Mohan, 1991).

Sridhar and Prasad (1996 a) reported about 86.9 per cent mortality of S. litura due to the entomopathogenic fungus on groundnut during 1991-1992 from Bapatla, a coastal region of Andhra Pradesh.

According to Kulkarni (1999) seasonal incidence of N. rileyi to S. litura in groundnut, soybean and potato was noticed between 32

nd (Aug 1

st week) to 40

th (October 1st week)

standard weeks. Among the three crops, maximum incidence was noticed in groundnut followed by soybean and least in potato.

Patil (2000) studied on the entomopathogenic fungus, N. rileyi occurred in epizootic form on S. litura in groundnut during the rainy season. N. rileyi was found to be more effective

against S. litura on groundnut and also found more persistent on groundnut foliage during kharif which was up to ten days.

According to Hegde (2001) the mycopathogen @ 2×108 conidia per litre sprayed

thrice against S. litura in potato at 15 days interval from 50 days after sowing proved as effective as SlNPV and Bt and reduced the defoliators up to 32 per cent.

Influence of host plants on the response of S. litura to N. rileyi indicated that larvae fed on groundnut were more susceptible by recording the lowest LC50 value of 5.79 × 10

6

conidia per litre followed by soybean 5.98 × 106 conidia per litre, potato 6.96 × 10

6 conidia per

litre and highest when feed on cotton 7.84 × 106 (Kulkarni and Lingappa, 2001).

According to Navi (2002) spraying of N. rileyi @ 1×1011

conidia per hectare was most

effective in soybean and groundnut in large scale demonstration in reducing larval population to the extent of 28 and 62 per cent in soybean, 33 and 77 per cent in groundnut after first and second spray respectively.

Manjula et al. (2004) record the occurrence of N. rileyi on S. litura and H. armigera in groundnut fields in Anantapur (Andhra Pradesh, India) and adjacent areas. The numbers of cadavers and live larvae were recorded at fortnightly intervals from September 2001 until the end of the cropping season. N. rileyi was initially observed during the first fortnight of September, and the level of infection gradually increased to 5-10, 25-50 and 50-100% during the second fortnight of September, first fortnight of October and second fortnight of October, respectively. These periods were characterized by a mean maximum temperature of 31-32

°C,

minimum temperature of 22-23°C, morning relative humidity (RH) of 79-84%, and evening RH

of 29-42%.

Nagaraja, (2005) reported that in groundnut crop ecosystem, different formulations of N. rileyi and spray equipments were evaluated, the results indicated that oil based formulation of N. rileyi with knapsack sprayer recorded significantly higher mycosis (47.43%), followed by wettable powder and crude formulation.

A field experiment was conducted during the 2001 kharif in medium black soils in India to study the effect of resistant (Dh-53, GPBD-4, Dh-74, Dh-86, Dh-22 (red), ICGV 86590, Dh-995, and Dh-22 (tan)) and susceptible genotypes (ICGV-92242 and Jl-24) of groundnut on the incidence of S. litura. The reduction of the larval population due to the spray of N. rileyi was compared with Neem Seed Kernel Extract (NSKE), insecticide (quinalphos 0.05%) spray. Insecticidal spray recorded significantly lower larval population (3.18, 2.53 and 0.82 larvae/m row at 40, 55 and 70 DAS, respectively) and leaflet damage in all the genotypes of groundnut. Significantly higher yield (16.89 q/ha) and lowest leaflet damage was recorded in quinalphos spray, whereas, N. rileyi and NSKE were next best in terms of yield (14.04 and 13.83 q/ha) with lesser leaflet damage (Navi et al., 2006).

Rachappa and Lingappa (2007) conducted experiments during 2000-01 and 2001-02 at Bailhongal and during 2000-01 and 2002-03 at Dharwad, Karnataka, India, to determine the seasonal occurrence of N. rileyi in relation to time and crop ecosystem. Fungal incidence was more abundant on pests inhabiting soyabean and groundnut ecosystems at both locations, e.g. Spodoptera litura, T. orichalcea and H. armigera. These crops, aside from being suitable for host insect build-up and providing congenial microclimate with their host, predisposed the insect larvae to higher and quicker infection.

2.2.5 Integrated pest management for Spodoptera litura (F.)

Mahesh (1996) reported that integration of raising tolerant varieties, raising trap crops like castor and sunflower around the fields and within the field respectively. These trap crops will act as perches for predatory birds and laying of eggs on the broader leaves as per the performance of the pest. Installation of pheromone traps to predict oviposition, application of neem seed kernel extract during early stages of the crop and spraying of NPV @ 250 LE per hectare will be a good management strategy for S. litura in groundnut.

Monitoring with pheromone traps to predict oviposition, growing sunflower and castor as trap crop around the field and 3-5 m apart within the fields, collection of egg masses and larvae from trap crop and destroying them on alternate days, spraying of NPV @ 250 LE/ ha at 36 days after sowing, release of egg parasitoid Telonomus remus Nixon @ 40,000/ ha at 39 days after sowing, spraying of NSKE @ 3% at 42 days after sowing and spraying of quinalphos @ 0.05% or chlorpyriphos @ 0.05% or endosulfan @ 0.07% from 52 days onwards when the pest reaches economic threshold level. Utility of these components will be effective in the S. litura management in groundnut (Prasad, 1996).

Ghewande and Nandagopal (1997) reported that the integration of resistant lines, intercropping with pearlmillet, soybean, castor and pigeonpea, use of pheromone traps and use of novel insecticides will be a good IPM strategy for major pests in groundnut.

Spraying of chlorpyriphos @ 3 ml/l or quinalphos @ 2 ml/l or acephate @ 1 g/l or monocrotophos @ 1.6 ml/l and keep pheromone traps (2/acre) in the field to attract the male moths has been recommended. Poison baiting with bran, jaggery and chlorpyriphos (10:1:1 w/w) is promising against grown up caterpillars which withstand contact insecticides as sprays. And planting castor or sunflower as trap crop for egg laying and destroying eggs or first stage larvae (on skeletonised leaf) help in reducing the incidence (Anon., 2000).

Field experiments were conducted to determine the effect of an integrated pest management module, exclusive use of insecticides and insecticide sprays on S. litura on groundnut in Tirupati, Andhra Pradesh, India, during 2000. Integrated pest management module consisting of seed treatment with imidacloprid and mancozeb (3 g/kg), use of trap crop (castor), manual picking of larvae and egg masses, use of pheromone trap, spraying of SlNPV at 250LE/ha and use of larval bait with chlorpyriphos (0.05%) proved significantly effective by managing the populations of S. litura and sucking pests on groundnut and gave higher yield and cost-benefit ratio compared with the chemical control schedule, consisting of sprays of monocrotophos (0.05%), chlorpyriphos (0.05%), quinalphos (0.05%) and endosulfan (0.07%), and farmers practice, i.e. spray with cypermethrin (0.02%) at 60 days after sowing (Sreenivasulu et al., 2002).

Singh et al. (2005a) reported that the IPM module, consisting seed treatment with Trichoderma viride Lieckfeldt @ 4 g/kg, foliar spray of NSKE (5%) applied at 30 DAS, foliar spray of sorghum leaf extract (10%) at 20 and 30 DAS, installation of pheromone traps @ 10/ha each for monitoring of S. litura, erecting of “T” shaped bamboo bird perches @ 60/ha and need based application of SINPV spray @ 250 LE/ha was effective pest management option for groundnut + sunflower (5:1) based production system.

Pest and disease incidence in groundnut plots maintained under integrated pest management (IPM; seed treatment with (Trichoderma) 4 g/kg of seeds, sowing through hand dibbling, intercropping with soybean cv. JS 335 and groundnut cv. Phule Unap at 4:1, soil amendment with 500 kg castor cake/ha, planting of castor bean as a trap crop, establishment of 10 pheromone traps/ha, and application of neem seed kernel extract (5%) at 30 and 50 days after sowing (DAS) and SlNPV (1.5x10

13POB’S/ha) or farmers' practice (FP; seed

drilling, sole crop of groundnut, and spraying of 0.03% dimethoate at 35 DAS and spraying of 0.07% endosulfan at 60 DAS) were studied in Jalgaon and Dhule districts of Maharashtra, India, during the rainy seasons (July-November) of 2003, 2004 and 2005. Infestation by thrips and leaf hopper was severe at 30-45 DAS. The average percentage of damage by thrips was lower in IPM plots (15-25%) than in FP plots (20-50%). S. litura and groundnut leaf miner were observed at 60 and 80 DAS, respectively. Damage was reduced by 5-25% when neem seed kernel extract and SlNPV were applied. The population of lady bird beetle was low in plots sprayed with insecticides. The incidence of soil borne diseases was reduced by 20-50% in IPM plots compared to FP plots. The intensity of foliar diseases, particularly late leaf spot (Cercosporidium personatum (Berk. & M.A. Curtis) Deighton [Mycosphaerella berkeleyi]), was lower under IPM (30%) than under FP (up to 80%). IPM resulted in higher net return (8345 rupees/ha, higher by 42.3 per cent and benefit-cost ratio (1.43 vs. 1.31) than FP (Shambharkar et al., 2006).

3. MATERIAL AND METHODS

The investigations on the objectives envisaged in previous chapter were carried out during kharif 2009 at Main Agricultural Research Station (MARS), University of Agricultural Sciences, Dharwad. Dharwad is located in Northern Transition Zone (Zone 8) of Karnataka and is situated at 15° 26' North latitude, 75° 07' East longitude and at an altitude of 678 m above mean sea level (MSL) and rainy climate. During experimental year the annual rainfall received was 1140.4 mm (69 rainy days), which was 31.9 per cent higher compared to the average of past 59 years. The air temperature, both minimum and maximum temperature did not vary much from the normal. However, relative humidity showed higher value compared to mean monthly average values.

The biology of Spodoptera litura on seven elite genotypes of groundnut was carried out under laboratory condition, the field screening and evaluation of IPM modules against major defoliators of groundnut were under taken at Main Agricultural Research Station UAS, Dharwad during 2009 kharif season. The details of the materials used and methodology adopted during the course of investigation are described below.

3.1 Field Screening

1. Plant material

Seven genotypes were screened against S. litura under artificial infestation in the field condition during 2009, rainy season. Each of the genotype was sown in three rows of 10 meters length with spacing of 30×10 cm. The genotypes were assessed for foliage damage due to S. litura.

2. Artificial infestation in the field

Egg masses of S. litura were collected from the unsprayed groundnut field. Those collected egg masses were pinned on the surface of young leaves (egg mass facing the leaf surface) in each genotype of three rows of 10 meters length when crop was 50 days old.

3. Scoring method

The leaf area damage by S. litura was scored when the crop was 70 days old (Prasad et al., 1998). Five leaflets on the main stem from top to bottom were used for the estimation of leaf area damaged, as the damage was confined to young leaflets showing difference among entries. The leaf area damaged (in per cent) was visually assessed by adopting 1-9 scale (Wightman and Ranga Rao, 1994). On the bases of 1-9 scale the genotypes were grouped into four categories 1-2, 2-4, 4-6 and > 6 visual damage grade. Observations on larvae per meter row and per cent defoliation of each variety were also taken.

3.1.1 Biology of Spodoptera litura on elite genotypes under laboratory conditions

The experimental material was raised in the field during 2009 rainy season. All the cultural practices as recommended on package of practice were adopted, except spraying of insecticides. Care was also taken to protect the plants from drifting of insecticide spray from neighbouring fields.

Egg masses of S. litura were collected from unsprayed groundnut fields. Uniform sized egg masses were surface sterilized with 10 per cent formaldehyde, washed 3-4 times with distilled water and kept in sterilized petriplates (5 cm diameter) for hatching on moist filter paper. Third leaf from top was selected for rearing. Freshly hatched hundred neonate larvae were released into seven trays containing seven genotypes viz.,

1. JL-24 (Susceptible check)

2. ICGV-86699 Red

3. GPBD- 5

4. ICGV-86699 Tan

5. GPBD- 6

6. Mutant III

7. GPBD-4, which were replicated trice.

The cut end of the fresh groundnut leaves were covered with wet cotton wad for maintaining freshness of the leaves. The open top of the tray was covered by muslin cloth secured with rubber band. Fresh leaves were provided daily morning after cleaning the tray.

Once the larvae attain third instar, only 25 larvae were maintained on each genotype. Before pupation, larvae were transferred to another tray containing sterilized sawdust. Two pairs of male and female pupae were kept for moth emergence in cages (35 × 25 × 45 cm) to study the oviposition period and fecundity. Diluted honey (10%) was provided as adult food in small vials with cotton wad. Groundnut plants placed in conical flask with water were kept inside the cage for egg laying. The following parameters were recorded.

Number of days required for completion for each larval instar, prepupa and pupa and also larval weight, larval mortality at 5, 10 and 15 days after hatching. Per cent pupal survival on each variety and pupal weight were recorded. Pre-oviposition, oviposition and post- oviposition period, adult longevity, per cent adult emergence and total life cycle were recorded.

3.2 IPM modules for Northern transitional zone of Karnataka

3.2.1 Mass multiplication of Nomuraea rileyi

The number of spores per ml was calculated using the following formula. For field studies the entomopathogenic fungus N. rileyi was cultured on Sabouraud’s Maltose Agar Yeast (SMAY) medium. For this, 200ml of the medium was put into conical flasks (500 ml), autoclaved at 15 PSI for 20 minutes, cooled and inoculated with pure culture of the fungus maintained in culture slants. Inoculated flasks were incubated at room temperature of 26 ± 1

°

C for 15 days. All the steps were carried out in aseptic conditions to avoid contamination. Spores were harvested with the help of a small sterile metal spatula and stored in small airtight screw type tubes at 10

° C and 60 per cent relative humidity.

The suspension of week old spores was made using distilled water and filtered through muslin cloth. Few drops of Tween-80, a wetting agent was added to the filtrate. From the stock solution, serial dilutions were made to obtain the required concentration.

Spore count was made using Neaubuar’s haemocytometer

Number of spores per unit = N × 400 × 1000 × 10 × D

Where,

N : Mean number of spores per small square of the haemocytometer.

D : Dilution factor

3.2.2 Preparation of Neem Seed Kernel Extract (NSKE)

� 5 kg of dehusked neem seeds have been taken

� Ground the neem seed kernals into fine powder

� Overnight soak fine powder in 10 liters of water

� Filtered it through muslin cloth and added 90 liters of water and 100 ml of soap solution to get 5 per cent NSKE (50 grams in 1 liter of water gives 5 per cent NSKE).

3.2.3 Evaluation of IPM modules

The experiment was carried out under field condition during kharif 2009 at the Main Agricultural Research Station, University of Agricultural Sciences, Dharwad. The trial was conducted to evaluate effects of three IPM modules on groundnut pests. The sowing was done during first fortnight of July, 2009 in all the modules. Each module was implemented on 1000 sq m (10 guntas) area with GPBD-4 variety which is having resistance to late leaf spot and spacing followed was 30×10 cm. The details of modules tested in the field are given below.

Module I:

� Seed treatment with Trichoderma @ 4 g/kg

� 200 grams of sunflower seeds were mixed with groundnut seeds

� Pheromone traps @ 2/acre installed after sowing for the monitoring of S. litura

� Mechanical removal of egg masses from both sunflower and groundnut periodically and

� Sprayed with Nomuraea rileyi @ 1×108 conidia /ml and NSKE @ 5% two times at 45

and 60 days after sowing.

Module II:

� Seed treatment with Trichoderma @ 4 g/kg

� Intercropping of groundnut with foxtail millet at the row proportion of 7:1 (7 rows of groundnut and 1 row of foxtail millet) and all along the experimental plot

� Pheromone traps @ 2/acre installed after sowing for the monitoring of S. litura

� Mechanical egg collection on main crop and

� Sprayed with Emamectin benzoate @ 0.2 g/l at 45 and 60 days after sowing

Module III: Farmer’s practice

� Insecticidal spray with quinalphos @ 2 ml/ l was taken up at 50 and 60 days after sowing

In all the three modules, the sprays were imposed 2 times at an interval of 15 days, at 45 and 60 days after sowing.

The observations were recorded, when there was a initial notice of both sucking and defoliating pests on groundnut.

� Observations were recorded daily on trap catches of S. litura

� The population count of sucking pests and defoliating pests were taken at weekly intervals

For sucking pests-

Five spots (per meter row) have been selected randomly in each module, from each spot the pest population on top three leaves of selected five plants was recorded

For defoliating pests-

Five spots have been selected randomly in each module, from each spot population (larvae) per meter row was recorded

� Natural enemy population in each module was recorded

� The leaf area damaged (in per cent) was visually assessed once in a week by adopting 1-9 scale on groundnut at randomly selected five spots.

� The leaf damage prior to spray and after spray at 7 and 15 days and also larvae per meter row were recorded.

� After the harvest, pod yield of groundnut and grain yield of both intercrop and trap crop were recorded.

Whereas, all other data were compared by using Paired‘t’ test.

3.2.4 Cost economics

Based on the yield data the gross returns and net returns were calculated for each module. The Cost-Benefit ratio (C:B) was determined by Gross returns divided by cost of cultivation for each module.

4. EXPERIMENTAL RESULTS

The results of the present study on biology of Spodoptera litura on seven elite genotypes and integrated pest management modules for groundnut pests was undertaken at Main Agricultural Research Station (MARS), University of Agricultural Sciences, Dharwad, during Kharif, 2009 and results presented here under.

4.1 Field screening of groundnut genotypes

Seven groundnut genotypes were screened against S. litura under artificial infestation in the field condition during 2009, rainy season. All the elite groundnut genotypes differed significantly in per cent defoliation and larval count (per m row).

The damage ranged from 11.5 to 44.0 per cent in different genotypes. Maximum defoliation and number of larvae / m row were observed in the JL-24 (44.0% and 4.0) followed by GPBD-4 (33.5% and 3.5). The genotypes viz., Mutant-III (11.5% and 1.0) and ICGV- 86699 Tan (12.0% and 1.0) recorded minimum damage and less number of larvae / m row. The damage and number of larvae were moderate in GPBD-5 (23.5% and 2.0), ICGV86699 RED (23.5% and 2.0) and GPBD-6 (28.5% and 2.0) (Table 1).

4.1.1 Biology of Spodoptera litura on elite genotypes under laboratory conditions

Spodoptera litura was reared on seven groundnut genotypes viz., JL-24, ICGV-86699 Red, GPBD- 5, ICGV-86699 Tan, GPBD- 6, Mutant III and GPBD- 4. Various parameters of growth and development of S. litura viz., number of days required for completion of each larval instar, prepupa, pupa, pre oviposition, oviposition, post oviposition and also larval weight, larval mortality at 5, 10 and 15 days after hatching, pupal weight, per cent survival on each variety, per cent adult emergence, adult longevity and total life cycle were studied.

4.1.1.1 Larval period

During the entire larval period, the caterpillar moulted five times. Thus completed six larval instars. A brief description of each larval instar is presented below (Table 2).

4.1.1.1.1 First Instar

Neonate larvae tiny, cylindrical and pale green with brown head. First abdominal segment has a pair of black spots. Three dorsal stripes were seen all along the body. Larvae congregated below the leaf at the site of egg laying. Scraped the epidermis which resulted in the papery leaf devoid of chlorophyll.

The duration of first instar varied from 1.75 to 2.00 days in different genotypes. But there was no significant difference between the genotypes tested.

4.1.1.1.2 Second instar

Except for increase in size, no marked change in body color was noticed. The larvae remained in congregation but moved little away from the previous site and scraped the chlorophyll resulting into thin papery leaf.

The duration of second instar was significantly longer (3.83 days) on the genotypes, ICGV- 86699 Tan followed by Mutant III (3.50 days) than on other except GPBD-4 on which the second instar duration was least 2.42 days.

4.1.1.1.3 Third instar

The larvae increased in size, turned pale green with brown head. A pair of black dots on first abdominal segment and three dorsal stripes all along the body were prominent. Larvae of this instar moved individually and punctured the leaflet.

Table 1: Performance of elite groundnut genotypes against Spodoptera litura damage under field condition during Kharif 2009

Sl. No. Genotypes Per cent

defoliation No. of larvae / m row

1 JL-24 (Susceptible check ) 44.0a

4.0a

2 ICGV86699 RED 23.5d

2.0c

3 GPBD-5 23.5d

2.0c

4 ICGV86699 TAN 12.0e

1.0d

5 GPBD-6 28.5cd

2.0c

6 MUTANT -III 11.5e

1.0d

7 GPBD-4 33.5bc

3.5b

S. Em ± 1.09 0.063

C.D. at 5% 3.31 0.019

C.V. (%) 13.0 8.53

In a column, means followed by the same alphabet do not differ significantly (P = 0.05) by DMRT

ICGV-86699 TAN (Resistant)

Mutant- III (Resistant)

JL-24 (Susceptible)

Plate.1. Resistant and susceptible genotypes of groundnut

Third instar duration was significantly longer on the genotypes ICGV-86699 Tan (3.83 days) and Mutant III (3.75 days) followed by GPBD-6 (3.25 days) and GPBD-5 (3.25 days) and were on par with JL-24 (3.08 days), GPBD-4 (3.00 days) and ICGV- 86699 Red (3.00 days).

4.1.1.1.4 Fourth instar

The color of the fourth instar larvae was grayish to black with a dark head and three white spots were observed on cervix. On meso and metathoracic segments white spots were seen on the lateral sides along the black stripes. The larvae got scattered from the egg laying site and fed on the leaves irregularly from the margin inwards.

The duration of fourth instar was significantly longer on the resistant genotypes, ICGV- 86699 Tan (4.33 days) and Mutant III (4.17 days) followed by GPBD-5 (3.83 days), GPBD-6 (3.67 days) and ICGV- 86699 Red (3.67 days). The shortest larval duration was recorded in susceptible genotypes GPBD-4 (3.25 days) and JL-24 (3.17 days).

4.1.1.1.5 Fifth instar

Considerable variation in the color ranging from light green to dark brown with a dark brown head was apparent. A prominent ‘Y’ shaped epicranial suture was present on the head. The lateral stripes were more clearly visible from a distance. Larvae were more gregarious and fed irregularly on the leaves from margin inwards.

The duration of fifth larval instar was significantly longer in the genotypes, ICGV- 86699 Tan (4.75 days) and Mutant III (4.58 days) followed by GPBD-5 (3.92 days), and GPBD-6 (3.90 days) and were on par with ICGV- 86699 Red (3.42 days). The least larval duration was recorded in susceptible genotypes GPBD-4 (3.33 days) and JL-24 (3.25 days).

4.1.1.1.6 Sixth instar

The full grown sixth instar larva was stout and smooth. It was dull grayish to blackish green in color with a bright yellow stripes bordered by semicircular stripe. Along the lower edge of lateral side of the body, dull yellow stripe was distinct. On the dark brown head inverted ‘Y’ shaped suture was prominent.

The duration of last instar was significantly longer in the resistant genotypes, ICGV- 86699 Tan (4.92 days) and Mutant III (4.83 days) followed by GPBD-5 (4.08 days), and GPBD-6 (4.09 days) and shortest larval duration was noticed in ICGV- 86699 Red (3.42 days).However, it was on par with JL-24 (3. 52 days) and GPBD-4 (3.50 days).

4.1.1.1.7 Total larval period

The total larval period on all the genotypes ranged from 17.33 to 23.67 days. The resistant genotypes, ICGV- 86699 Tan and Mutant III permitted the larvae to complete their development in longer period (23.67 days and 22.83 days respectively) followed by GPBD-5 (19.75 days) and GPBD-6 (19.49 days) and ICGV- 86699 Red (18.17 days). The susceptible varieties JL-24 and GPBD-4 allowed the larvae to complete their larval period within shortest period (17.93 days and 17.33 days) (Table 2).

4.1.1.2 Larval weight

Mean of 20 larval weight was recorded on each genotype at 5, 10 and 15 days after hatching. The weight gain by the larvae after 5 days after hatching (DAH) was maximum on susceptible genotypes, JL-24 (0.08 g) and GPBD-4 (0.08 g) followed by GPBD-5 (0.06 g) and minimum weight was recorded in resistant genotypes, ICGV- 86699 Tan (0.02 g) and Mutant III (0.02 g) and remaining genotypes were on par with each other (Table 3).

After 10 DAH, the larval weight was significantly highest on JL-24 (1.98 g) and GPBD-4 (1.91 g) followed by GPBD-6 (1.44 g), GPBD-5 (1.41 g) ICGV-86699 Red (1.28 g).

Table 2: In vitro larval duration (in days) of Spodoptera litura on elite groundnut genotypes

Larval instar duration (in days)

Sl. No. Genotypes

1st instar 2

nd instar 3

rd instar 4

th instar 5

th instar 6

th instar Total

1 GPBD-5 2.00 a

2.67c

3.25ab

3.83ab

3.92b

4.08b

19.75 b

2 ICGV-86699 Red 1.83 a

2.83c

3.00b

3.67ab

3.42bc

3.42c

18.17cd

3 ICGV-86699 Tan 2.00 a

3.83a

3.83a

4.33a

4.75a

4.92a

23.67 a

4 GPBD-6 1.75 a

2.92bc

3.25ab

3.67ab

3.90b

4.09b

19.49 bc

5 Mutant-III 2.00 a

3.50ab

3.75a

4.17a

4.58a

4.83a

22.83 a

6 GPBD-4 1.83 a

2.42c

3.00b

3.25b

3.33bc

3.50c

17.33 d

7 JL-24 (Susceptible check) 2.00 a

2.92bc

3.08b

3.17b 3.25

c 3.52

c 17.93

d

S. Em ± 0.11 0.14 0.14 0.18 0.14 0.12 0.32

C.D.at 1% NS 0.56 0.59 0.71 0.59 0.49 1.26

In a column, means followed by the same alphabet do not differ significantly (P = 0.01) by DMRT

Table 3: Gain in larval weight and larval mortality of Spodoptera litura at different days after hatching on elite groundnut genotypes under laboratory conditions

Mean of 20 larval weight (g) Larval mortality (%) Total

mortality Sl. No. Genotypes

5 DAH 10 DAH 15 DAH 5 DAH 10 DAH 15 DAH (%)

1 GPBD-5 0.06a

1.41ab

10.30ab

31.67ab

6.67b

16.80ab

55.14

2 ICGV-86699 Red 0.05ab

1.28ab

9.92b

29.33b

5.53b

12.55b

47.41

3 ICGV-86699 Tan 0.02b

0.79b

7.12c

41.00a

9.67a

25.27a

75.95

4 GPBD-6 0.05ab

1.44ab

10.31ab

30.67ab

7.00ab

15.11ab

52.78

5 Mutant-III 0.02b

0.82b

6.13c

41.33a

9.67a

25.47a

76.47

6 GPBD-4 0.08a

1.91a

11.99a

27.00b

5.67b

13.00b

45.67

7 JL-24 (Susceptible check) 0.08a

1.98a

11.70a

28.00b

5.67b

12.93b

46.60

S. Em. ± 0.007 0.20 0.38 2.45 0.65 2.46

C.D. at 1% 0.029 0.80 1.51 9.82 2.65 9.84

In a column, means followed by the same alphabet do not differ significantly (P = 0.01) by DMRT DAH: Days after hatching

The least larval weight recorded in ICGV- 86699 Tan (0.79 g) and Mutant III (0.82 g). However, after 15 DAH larvae reared on GPBD-4 and JL-24 registered significantly higher weight gain (11.99 g and 11.70 g) and the least larval weight was recorded in ICGV- 86699 Tan (7.12 g) and Mutant-III (6.13 g). The genotypes GPBD-6 (10.31 g), GPBD-5 (10.30 g) and ICGV-86699 Red (9.92 g) were intermediate in gaining the weight.

4.1.1.3 Larval mortality (%)

Per cent larval mortality at 5, 10 and 15 DAH varied significantly between the genotypes evaluated. Significantly high larval mortality was recorded on resistant genotypes at all the stages compared to susceptible genotypes.

The per cent larval mortality after 5 DAH Significantly high on resistant genotypes Mutant III (41.33%) and ICGV- 86699 Tan (41.00%) compared to susceptible genotypes ICGV-86699 Red (29.33%), JL-24 (28%) and GPBD-4 (27%) followed by GPBD-5 (31.67%) and GPBD- 6 (30.67%) (Table 3).

After 10 DAH, the per cent larval mortality was significantly more on ICGV- 86699 Tan (9.67%) and Mutant III (9.67%) followed by GPBD-6 (7.00%) and less larval mortality was noticed on the genotype ICGV-86699 Red (5.53%) and it was on par with JL-24 (5.67%) and GPBD-4 (5.67%). However, after 15 DAH larvae reared on ICGV- 86699 Tan and Mutant III registered significantly high larval mortality (25.27% and 25.47%) followed by GPBD-5 (16.80 %), GPBD-6 (15.11%). The genotypes ICGV-86699 Red (12.55%), JL-24 (12.93%) and GPBD-4 (13.00%) were intermediate in larval mortality.

4.1.1.4 Total per cent mortality

Total per cent mortality was significantly highest on the genotypes Mutant III (76.47%) and ICGV- 86699 Tan (75.95%) and it was lowest on GPBD-4 (45.67%) and it was on par with JL-24 (46.60%) and ICGV-86699 Red (47.41%). Whereas GPBD-5 (55.14%), GPBD-6 (52.14%) were intermediate in total per cent mortality (Table 3).

4.1.1.5 Pupal weight

Mean of 15 pupal weight was recorded on each genotype at a day after pupation. Pupal weight varied significantly between the genotypes evaluated. The highest pupal weight was recorded on the susceptible genotypes, JL-24 (4.66 g) and GPBD-4 (4.63 g) followed by GPBD-5 (4.27 g), GPBD-6 (4.21 g) and ICGV-86699 Red (3.93 g). The lowest pupal weight was recorded on ICGV- 86699 Tan (3.07 g) and Mutant III (2.98 g) (Table 4).

4.1.1.6 Per cent pupal survival

Per cent pupal survival on each variety varied significantly. The per cent pupal survival was highest on the genotypes, GPBD-4 (49.67%), JL-24 (48.00%).Which were on par with ICGV-86699 Red (46.67%) and per cent pupal survival was lowest on ICGV- 86699 Tan (20.67 %) and Mutant III (19.00%).Whereas GPBD-6 (43.00%) and GPBD-5 (40.00%) were intermediate in per cent pupal survival (Table 4).

4.1.1.7 Percentage of adult emergence

Percentage of adult emergence was significantly least on ICGV- 86699 Tan (16.72%) and Mutant III (14.94%) and it was highest in the genotypes GPBD-4 (46.38%) and JL-24 (46.08%). Which were on par with ICGV-86699 Red (38.70 %) and GPBD-6 (38.48%) (Table 4).

4.1.1.8 Adult longevity

Adult longevity was maximum on susceptible genotypes JL-24 (11.83 days) and GPBD-4 (11.67 days) followed by GPBD-6 (10.25 days), GPBD-5 (10.17 days) and minimum

Table 4: Biological parameters of Spodoptera litura on elite groundnut genotypes under laboratory conditions

Sl. No. Genotypes Mean of 15 pupal

weight (g) Pupal survival (%)

Adult emergence (%)

Adult longevity (days)

Fecundity (eggs/ female)

1 GPBD-5 4.27 ab

40.00 b 30.79

b 10.17

b 520.67

ab

2 ICGV-86699 Red 3.93ab

46.67 ab

38.70 ab

9.58b

492.67ab

3 ICGV-86699 Tan 3.07b

20.67c

16.72 c 9.33

b 386.00

b

4 GPBD-6 4.21 ab

43.00 ab

38.48 ab

10.25b

517.00 ab

5 Mutant-III 2.98 b 19.00

c 14.94

c 9.67

b 379.67

b

6 GPBD-4 4.63 a 49.67

a 46.38

a 11.67

a 588.67

a

7 JL-24 (Susceptible check) 4.66a

48.00 a 46.08

a 11.83

a 592.00

a

S. Em. ± 0.31 1.57 2.38 0.23 30.75

C.D. at 1% 1.24 6.28 9.00 0.92 123.23

In a column, means followed by the same alphabet do not differ significantly (P = 0.01) by DMRT

on ICGV- 86699 Tan (9.33 days) and it was on par with Mutant III (9.67 days) and ICGV-86699 Red (9.58 days) (Table 4).

4.1.1.9 Fecundity

There was greater variation in the fecundity. JL-24 and GPBD-4 established their superiority in recording significantly higher number of eggs / female (592.0 and 588.67) followed by GPBD-5 (520.67), GPBD-6 (517.0), ICGV-86699 Red (492.67) and the least number of eggs were recorded in ICGV- 86699 Tan (386.0) and Mutant III (379.0) (Table 4).

4.1.1.10 Pre-pupal period

The fully developed larvae gradually shrunk and entered prepupal stage. There was no significant difference in the pre-pupal period in genotypes, thus pre pupal period did not vary between the genotypes (Table 5).

4.1.1.11 Pupal period

There was further reduction in the length of the prepupa and it transformed into a pupa. The pupa was brown, obtect with prominent compound eyes.

The total pupal period was significantly minimum on susceptible genotypes, JL-24 (9.83days) and GPBD-4 (9.75 days).Whereas Mutant III (11.67 days) and ICGV- 86699 Tan (11.33 days) recorded maximum pupal period and GPBD-5 (10.33 days), GPBD-6 (10.25 days) and ICGV- 86699 Red (10.17days) were intermediate in pupal duration (Table 5).

4.1.1.12 Pre-oviposition period

Pre-oviposition period was significantly extended on resistant genotypes, Mutant III (4.25 days) and ICGV- 86699 Tan (4.17 days) and the Pre-oviposition period was least on JL-24 (3.08 days) and it was on par with GPBD-6 (3.50 days), GPBD-5 (3.42 days), GPBD-4 (3.33 days) and ICGV- 86699 Red (3.25 days) (Table 5).

4.1.1.13 Oviposition period

Oviposition period was significantly higher on GPBD-4 (4.92 days) followed by JL-24 (4.83 days) and least on Mutant III (4.25 days) and ICGV- 86699 Tan (4.17 days). Whereas GPBD-5 (4.42 days), GPBD-6 (4.42 days) and ICGV- 86699 Red (4.33 days) were intermediate in oviposition period (Table 5).

4.1.1.14 Post-oviposition period

GPBD-4 (4.00 days) showed significantly higher post-oviposition period. Whereas Mutant III (3.25 days) and ICGV-86699 Tan (3.17 days) recorded least post-oviposition period followed by GPBD-6 (3.58 days) and GPBD-5 (3.50 days) and were on par with ICGV- 86699 Red (3.33 days) (Table 5).

4.1.1.7 Total developmental period (egg-adult)

The total developmental period was significantly least on JL-24 (41.02 days), GPBD-4 (41.00 days) and ICGV-86699 Red (41.17 days) when compared to ICGV-86699 Tan (49.00 days) and Mutant III (48.92 days). Whereas GPBD-5 (43.33 days) and GPBD-6 (43.15 days) were intermediate in total developmental period and were on par with each other (Table 5).

4.2 Evaluation of IPM modules in groundnut

Three different IPM modules viz., (1) the effective IPM modules developed against S. litura (M-I) involving seed treatment with Trichoderma, sunflower as trap crop, pheromone traps, spraying of N. rileyi and NSKE was imposed (2) in this module (M-II) instead of

Table 5: In vitro biology of Spodoptera litura on elite groundnut genotypes

Duration (in days)

Sl. No. Genotypes

Larval period Pre pupal

period Pupal period

Pre oviposition

period

Oviposition period

Post oviposition

period

Total development

al period (egg-adult)

1 GPBD-5 19.75 b 1.75

a 10.33

abc 3.42

b 4.42

abc 3.50

abc 43.33

b

2 ICGV-86699 Red 18.17cd

1.58 a

10.17 abc

3.25 b 4.33

bc 3.33

bc 41.17

c

3 ICGV-86699 Tan 23.67 a 2.17

a 11.33

ab 4.17

a 4.17

c 3.17

c 49.00

a

4 GPBD-6 19.49 bc

1.67 a 10.25

abc 3.50

b 4.42

abc 3.58

abc 43.15

b

5 Mutant-III 22.83 a 2.08

a 11.67

a 4.25

a 4.25

c 3.25

c 48.92

a

6 GPBD-4 17.33 d 1.75

a 9.75

c 3.33

b 4.92

a 4.00

a 41.00

c

7 JL-24 (Susceptible check) 17.93d

1.67 a

9.83 bc

3.08 b 4.83

ab 3.92

ab 41.02

c

S. Em. ± 0.32 0.16 0.32 0.14 0.12 0.12 0.34

C.D. at 1% 1.26 NS 1.28 0.56 0.49 0.48 1.36

In a column, means followed by the same alphabet do not differ significantly (P = 0.01) by DMRT

Module II (Groundnut + Foxtail millet)

Module I (Groundnut + Sunflower)

Module III (Farmers practice)

Plate.2. IPM modules take up in groundnut

sunflower and N. rileyi, foxtail millet used as intercrop and Emamectin benzoate used for spraying where as other treatments remained same as that of M-I. These two modules were compared with M-III which comprised of farmer’s practice. The results obtained are presented in tables.

4.2.1 Monitoring the activity of S. litura

The daily trap catches of male adults of S. litura in pheromone traps during Kharif 2009 indicated definite pattern of occurrence during August and September (Apendix-I).

In first module

During the cropping season, the maximum number of moths were caught on fourth day of second week of August (451.0) and minimum number of moths were caught on fourth day of third week of August (13.0). The maximum number of adults were caught during first and second week of August. The least number of moths were caught on fifth day of first week of September (18.0) and maximum (75.0) on seventh day of second week. In September month, the maximum number of adults were caught during second week compare to other weeks.

In second module

During August month, the maximum number of moths were caught on fifth day of third week (159.0) and the minimum (18.0) number of moths on first day of fourth week. During September month, the highest number of moths caught on seventh day of second week (112.0) and lowest (13.0) on fourth day of first week. In second module, the highest number of moths were caught during first week of August compare to September.

Between Module-I and II, the highest number of moths were caught in Module-I compare to Module –II.

4.2.2 Sucking pest population in different IPM modules of groundnut

4.2.2.1 Thrips (Scirtothrips dorsalis and Thrips palmi)

Nymphs and adults were found sucking the sap from leaves, starting from 21 DAS to 63 DAS. Population of thrips ranged from 2.60 to 3.28 /top three leaves in M-I. In M-II it was ranged from 1.40 to 2.48. In case of third module the thrips population was varied from 3.16 to 3.84 (Table 6).

As per Paired ‘t’ value, there was significant variation in sucking pest population in different IPM modules. Module-II was significantly superior over module-I and module-III during 21 DAS to 63 DAS. Whereas module-I was significantly superior over module-III during same period.

4.2.2.2 Leafhoppers (Empoasca kerri)

Leafhoppers population found to attack the crop from 21 DAS to 63 DAS with the population of 1.44 to 2.24 / top three leaves in M-I. In M-II, the population of leafhoppers ranged from 1.24 to 2.38. In module-III (farmer’s practice) the population varied from 2.40 to 3.45/ top three leaves (Table 7).

As per Paired ‘t’ value, all the three modules varied significantly from each other. Module-II was significantly superior over module-I and module-III during 21 DAS to 63 DAS. However module-I was significantly superior over module-III during 21 DAS to 63 DAS.

4.2.3 Defoliator population in different IPM modules of groundnut

4.2.3.1 Semilooper (Thysanoplusia orichalcea)

This pest was observed on the crop from 37 DAS to 79 DAS. The young caterpillars scraped the chlorophyll content of the tender leaves from undersurface. Later instars caused

Table 6: Thrips population in different IPM modules of groundnut

Thrips population / top 3 leaves

Treatment

21 DAS 28 DAS 35 DAS 42 DAS 49 DAS 56 DAS 63 DAS

Module I

(Groundnut + sunflower) 2.60 2.68 3.28 3.24 3.12 3.00 2.80

Module II

(Groundnut + foxtail millet) 2.00 2.12 2.40 2.48 2.24 1.80 1.40

Module III

(Farmers’ practice) 3.16 3.28 3.84 3.72 3.56 3.40 3.36

Paired “ t” test value for comparison of means

Module I & Module II 3.35* 2.88* 3.22* 3.28* 2.99* 5.26* .37*

Module II & Module III 5.98* 7.89* 2.88* 6.07* 3.65* 7.62* 7.89*

Module III & Module I 2.88* 3.58* 3.58* 4.70* 5.87* 3.65* 3.50*

* Significant at 5% level DAS- Days after sowing Module-I : Seed treatment with Trichoderma, sunflower (trap crop), pheromone trap and spraying of N. rileyi and NSKE Module-II : Seed treatment with Trichoderma, foxtail millet (intercrop), pheromone trap and spraying of Emamectin benzoate Module-III: Spraying of quinalphos

Table 7: Leaf hoppers population in different IPM modules of groundnut

Leafhoppers population / top 3 leaves

Treatment

21 DAS 28 DAS 35 DAS 42 DAS 49 DAS 56 DAS 63 DAS

Module I

(Groundnut + sunflower) 2.48 2.24 2.87 2.51 2.47 1.88 1.44

Module II

(Groundnut + foxtail millet) 2.00 2.38 2.16 2.06 2.00 1.48 1.24

Module III (Farmers’ practice) 3.16 3.00 3.44 3.36 3.45 2.60 2.40

Paired “ t” test value for comparison of means

Module I & Module II 2.95* 1.25 7.88* 2.78* 2.93* 6.53* 0.95

Module II & Module III 5.98* 2.90* 9.58* 5.12* 5.74* 3.31* 83*

Module III & Module I 2.56* 2.97* 2.86* 2.97* 3.57* 3.08* 5.57*

* Significant at 5% level DAS- Days after sowing Module-I : Seed treatment with Trichoderma, sunflower (trap crop), pheromone trap and spraying of N. rileyi and NSKE Module-II : Seed treatment with Trichoderma, foxtail millet (intercrop), pheromone trap and spraying of Emamectin benzoate Module-III: Spraying of quinalphos

severe defoliation. Their population varied from 1.24 to 1.72 larvae / m row in first module. Whereas in second module, the population varied from 0.44 to 0.68 and in case of third module the population ranged between 2.00 to 2.48 (Table 8).

As per Paired ‘t’ value, all the three modules differed significantly from each other. Module-II was significantly superior over module-I and module-III during 37 DAS to 79 DAS. Whereas module-I was significantly superior over module-III during same period.

4.2.3.2 Tobacco caterpillar (Spodoptera litura)

This pest was noticed on the crop from 37 DAS to 79 DAS. They were gregarious in early instars and scraped the chlorophyll content from under surface of leaves, resulted in skeletonisation. Later instars spread and fed on leaves voraciously. The population varied from 1.48 to 3.96 larvae/ m row in first module. Whereas in second module, the S.litura population ranged from 0.76 to 3.08 and it was varied from 2.56 to 4.40 in third module (Table 9).

As per Paired ‘t’ value, all the three modules varied significantly from each other. Module-II was significantly superior over module-I and module-II during 37 DAS to 79 DAS. However module-I was significantly superior over module-III during same period.

4.2.3.3 Bihar hairy caterpillar (Spilactia obliqua)

Larvae scraped the green matter from under surface of leaves and skeletonised them in the early instars. The grown up caterpillars defoliated the crop. This pest was found to attacked the crop 37 DAS to 79 DAS. In M-I the larval number varied from 0.78 to 1.11 / m row. Whereas in M-II it was varied from 0.28 to 0.70 larvae /m row. However in M-III, the larval population ranged from 1.04 to 1.69 (Table 10).

As per Paired ‘t’ value, all the three modules varied significantly from each other. Module-II was significantly superior over module-I and module-III during 37 DAS to 79 DAS. The same trend was followed with module-I and module-III.

4.2.3.4 Groundnut leaf miner (Aproraema modicella)

Infestation was noticed on the crop for a short period from 51 DAS to 72 DAS. The larvae were mining into midrib of the leaves and feeding on the mesophyll between the two epidermal layers for a week and comes out from mine and webbing the leaves and feeding on them. At later stage to give burnt appearance of leaves from a distance. The population of GLM varied from 0.92 to 1.20 larvae/ plant in M-I. Whereas in M-II, the leaf miner population ranged from 0.36 to 0.50 and in M-III, it was varied from 1.82 to 2.04 (Table 11). Though the pest population was below ETL in all the IPM modules.

Paired ‘t’ value, all the three modules differed significantly from each other. Module-II was significantly superior over module-I and module-III during 51 DAS to 72 DAS. However module-I was significantly superior over module-III during same period.

4.2.4 Per cent defoliation by defoliators in different IPM modules of groundnut

4.2.4.1 35 days after sowing

The per cent defoliation was highest in module-III (36.6) followed by module-I (26.4) and lowest in module-II (22.8) at 35 days after sowing. As per Paired ‘t’ value, all the three modules differ significantly from each other (Table 12).

Table 8: Thysanoplusia orichalcea population in different IPM modules of groundnut

Thysanoplusia orichalcea population / m row

Treatment

37 DAS 44 DAS 51 DAS 58 DAS 65 DAS 72 DAS 79 DAS

Module I

(Groundnut + sunflower) 1.24 1.64 1.72 1.68 1.71 1.56 1.44

Module II

(Groundnut + foxtail millet) 0.68 0.48 0.52 0.53 0.58 0.50 0.44

Module III

(Farmers’ practice) 2.48 2.00 2.16 2.12 2.14 2.06 2.20

Paired “ t” test value for comparison of means

Module I & Module II 2.88* 5.20* 5.47* 4.46* 5.23* 4.16* 4.56*

Module II & Module III 7.89* 7.05* 9.75* 9.47* 10.67* 10.09* 10.22*

Module III & Module I 6.76* 2.59 3.77* 3.31* 3.26* 2.30 2.96*

* Significant at 5% level DAS- Days after sowing Module-I : Seed treatment with Trichoderma, sunflower (trap crop), pheromone trap and spraying of N. rileyi and NSKE Module-II : Seed treatment with Trichoderma, foxtail millet (intercrop), pheromone trap and spraying of Emamectin benzoate Module-III: Spraying of quinalphos

Table 9: Spodoptera litura population in different IPM modules of groundnut

Spodoptera litura population/ m row

Treatment

37 DAS 44 DAS 51 DAS 58 DAS 65 DAS 72 DAS 79 DAS

Module I

(Groundnut + sunflower) 1.48 2.20 2.16 2.80 3.60 3.80 3.96

Module II

(Groundnut + foxtail millet) 0.76 1.60 1.48 2.36 2.84 3.00 3.08

Module III

(Farmers’ practice) 2.56 3.20 3.28 3.60 4.04 4.20 4.40

Paired “ t” test value for comparison of means

Module I & Module II 3.49* 2.86* 3.47* 3.77* 3.91* 3.38* 4.74*

Module II & Module III 7.89* 9.56* 8.58* 10.63* 6.70* 4.47* 6.73*

Module III & Module I 5.24* 4.76* 8.25* 4.21* 5.87* 3.16* 3.77*

* Significant at 5% level DAS- Days after sowing Module-I : Seed treatment with Trichoderma, sunflower (trap crop), pheromone trap and spraying of N. rileyi and NSKE Module-II : Seed treatment with Trichoderma, foxtail millet (intercrop), pheromone trap and spraying of Emamectin benzoate Module-III: Spraying of quinalphos

Table 10: Spilarctia obliqua population in different IPM modules of groundnut

Spilarctia obliqua population / m row

Treatment

37 DAS 44 DAS 51 DAS 58 DAS 65 DAS 72 DAS 79 DAS

Module I

(Groundnut + sunflower) 0.78 0.82 0.90 0.95 0.99 1.09 1.11

Module II

(Groundnut + foxtail millet) 0.28 0.32 0.36 0.38 0.43 0.64 0.70

Module III

(Farmers’ practice) 1.04 1.10 1.12 1.20 1.29 1.60 1.69

Paired “ t” test value for comparison of means

Module I & Module II 2.79* 3.95* 5.01* 4.42* 5.20* 3.77* 4.21*

Module II & Module III 4.75* 7.00* 5.17* 9.85* 8.29* 3.53* 6.54*

Module III & Module I 4.33* 3.81* 1.62 2.98* 3.35* 6.50* 3.71*

* Significant at 5% level DAS- Days after sowing Module-I : Seed treatment with Trichoderma, sunflower (trap crop), pheromone trap and spraying of N. rileyi and NSKE Module-II : Seed treatment with Trichoderma, foxtail millet (intercrop), pheromone trap and spraying of Emamectin benzoate Module-III: Spraying of quinalphos

Table 11: Aproraema modicella population in different IPM modules of groundnut

Aproraema modicella population / plant

Treatment

51 DAS 58 DAS 65 DAS 72 DAS 79 DAS 86 DAS

Module I

(Groundnut + sunflower) 0.92 1.00 1.20 1.08 - -

Module II

(Groundnut + foxtail millet) 0.36 0.44 0.48 0.50 - -

Module III

(Farmers’ practice) 1.82 1.94 2.00 2.04 - -

Paired “ t” test value for comparison of means

Module I & Module II 4.63* 3.25* 3.02* 2.88* - -

Module II & Module III 6.69* 4.48* 4.41* 6.01* - -

Module III & Module I 6.28* 3.98* 4.20* 6.00* - -

* Significant at 5% level DAS- Days after sowing Module-I : Seed treatment with Trichoderma, sunflower (trap crop), pheromone trap and spraying of N. rileyi and NSKE Module-II : Seed treatment with Trichoderma, foxtail millet (intercrop), pheromone trap and spraying of Emamectin benzoate Module-III: Spraying of quinalphos

4.2.4.2 50 days after sowing

The defoliation percentage was more (39.8) in module-III followed by module-I (35.8) and less (29.0) in module –II and at 50 days after sowing. All the three modules varied significantly from each other as per Paired ‘t’ value (Table 12).

4.2.4.3 65 days after sowing

The per cent defoliation was highest in module-III (25.2) followed by module-I (22.2) and least in module-II (16.4) at 65 days after sowing. As per Paired ‘t’ value, all the three modules differ significantly from each other (Table 12).

4.2.5 The management of Spodoptera litura in IPM modules of groundnut

The management of Spodoptera litura in IPM modules of groundnut is given in table 13. Two sprays 45 and 60 days after sowing was done and observations have taken. All the three treatments differed significantly in percent defoliation before spraying in both the cases. Module III has shown significantly higher defoliation percentage (43.6, 24.4) followed by module I (37.8, 17.4) and lowest observed in module II (31.8, 15.4) in first and second spray respectively.

In first spray, 7DAS defoliation percentage and larvae per mt row were counted. All three treatments differed significantly in both the observations. Module III reported significantly highest defoliation and larvae (39.8 and 4.2) followed by module I (35.8 and 3.2) and the module II showed less defoliation and larvae (29.0 and 2.2). Observations taken 15 DAS also showed the same trend showing significantly higher defoliation and larvae in module III (25.2 and 3.8) followed by module I (22.2 and 3.0) and lowest in module II (16.4 and 1.6).

In second spray, 7DAS per cent defoliation and larvae per mt row were recorded. All three treatments varied significantly in both the observations. M- III showed significantly highest defoliation and larvae (24.4 and 3.6) followed by M-I (21.2 and 2.6) and the M -II showed less defoliation and larvae (15.4 and 1.8). Observations taken 15 DAS also followed the same trend showing significantly higher defoliation and larvae in M-III (19.4 and 3.4) followed by M-I (17.4 and 2.0) and lowest in M- II (12.4 and 1.2).

4.2.6 Incidence of sucking and defoliating insect pest on sunflower crop

4.2.6.1 Sucking pests

Leafhoppers, both nymphs and adults were found to suck the plant sap, starting from 21 DAS to 63 DAS. The leafhopper population varied from 1.02 to 2.04 / top three leaves with an average of 1.49 ± 0.32 (Table 14).

Thrips, Thrips palmi were noticed on the crop from 21 DAS to 63 DAS. The population of thrips ranged from 1.42 to 2.64 / top three leaves with an average of 1.24 ± 0.29. The nymphs and adults were found to attack and suck the sap from the tender leaves (Table 14).

Aphids, Aphis sp were observed on the crop from 21 DAS to 63 DAS. Both nymphs and adults were found feeding around succulent parts and under surface of tender leaves. The aphid population differed from 0.86 to 1.84 per top three leaves with the mean value of 1.28 ± 0.34.

4.2.6.2 Defoliators

Semilooper, Thysanoplusia orichalcea was noticed on the crop from 37 DAS to 79 DAS.

Table 12: Per cent defoliation by defoliators at 35, 50 and 65 days after sowing in different IPM modules

Defoliation (%) by defoliators

Treatment

35 DAS 50 DAS 65 DAS

Module I

(Groundnut + sunflower) 26.4 35.8 22.2

Module II

(Groundnut + foxtail millet) 22.8 29.0 16.4

Module III

(Farmers’ practice) 36.6 39.8 25.2

Paired “ t” test value for comparison of means

Module I & Module II 3.09* 2.81* 2.81*

Module II & Module III 4.81* 4.22* 4.00*

Module III & Module I 3.45* 3.81* 4.73*

* Significant at 5% level DAS- days after sowing Module-I : Seed treatment with Trichoderma, sunflower (trap crop), pheromone trap and spraying of N. rileyi and NSKE Module-II : Seed treatment with Trichoderma, foxtail millet (intercrop), pheromone trap and spraying of Emamectin benzoate Module-III: Spraying of quinalphos

Table 13: The management of Spodoptera litura in IPM modules of groundnut during Kharif 2009

First spray (45 days after sowing) Second spray (60 days after sowing)

After spray After spray

7 DAS 15 DAS 7 DAS 15 DAS Treatments

Before

Spray

( per cent defoliation)

Defoliation (%)

larvae/ mt row

Defoliation (%)

larvae/ mt row

Before spray

( per cent defoliation) Defoliation

(%) larvae/ mt

row Defoliation

(%) larvae/ mt

row

Module I

(Groundnut + sunflower) 37.8 35.8 3.20 22.2 3.00 22.2 21.2 2.6 17.4 2.00

Module II

(Groundnut + foxtail millet) 31.8 29.0 2.20 16.4 1.60 16.4 15.4 1.8 12.4 1.20

Module III

(Farmers’ practice) 43.6 39.8 4.20 25.2 3.80 25.2 24.4 3.6 19.4 3.40

Paired “ t” test value for comparison of means

Module I & Module II 2.89* 2.81* 3.16* 2.81* 3.50* 2.81* 5.43* 3.62* 4.38* 4.00*

Module II & Module III 4.35* 4.22* 6.32* 4.00* 11.0* 4.00* 5.81* 4.83* 5.53* 4.47*

Module III & Module I 5.98* 3.81* 3.16* 4.73* 3.16* 4.73* 6.53* 7.40* 6.32* 3.50*

* Significant at 5% level DAS- days after spray Module-I : Seed treatment with Trichoderma, sunflower (trap crop), pheromone trap and spraying of N. rileyi and NSKE Module-II : Seed treatment with Trichoderma, foxtail millet (intercrop), pheromone trap and spraying of Emamectin benzoate Module-III: Spraying of quinalphos

Table 14: Incidence of sucking and defoliating insect pests on sunflower (Trap crop)

Sucking pests / top 3 leaves Defoliator population/ plant

Weekly interval

Leaf hoppers Thrips Aphids

Weekly interval

T. orichalcea S. litura S. obliqua

21 DAS 1.42 2.64 1.42 37 DAS 2.68 1.86 1.48

28 DAS 1.64 2.26 1.64 44 DAS 4.42 3.64 2.86

35 DAS 1.02 1.42 1.02 51 DAS 2.28 5.18 4.08

42 DAS 1.24 1.68 0.86 58 DAS 2.46 6.28 5.48

49 DAS 1.86 2.16 1.84 65 DAS 1.86 9.86 7.68

56 DAS 2.04 1.82 1.48 72 DAS 2.06 11.06 10.06

63 DAS 1.42 2.24 1.06 79 DAS 1.64 13.84 11.56

Mean± SD 1.49 ± 0.32 ± 0.29 1.28± 0.34 Mean± SD 2.43±0.86 7.38±3.99 6.17±3.47

DAS - days after sowing

The early instar larvae scraped the chlorophyll content of the leaves from undersurface. Later instars caused severe defoliation. Their population varied from 1.64 to 4.42 with an average of 2.43 ± 0.86 larvae / plant.

Tobacco caterpillar, Spodoptera litura was observed during vegetative stage of the crop from 37 DAS to 79 DAS. Early instars larvae were gregarious and scraped the chlorophyll content from under surface of leaves, resulted in skeletonisation. Later instars spread and fed on leaves voraciously. The population ranged between 1.86 to 13.84 larvae/ plant. Initially the population was less (1.86 larvae/ plant) whereas gradually the population was increased (13.84 larvae/ plant) with the mean value of 7.38 ± 3.99.

Bihar hairy caterpillar, Spilosoma obliqua scraped the green mater from under surface of leaves and skeletonised them in the early instars. The grown up caterpillar defoliated the crop. This pest was noticed on the crop from 37 DAS to 79 DAS with mean larval population of 6.17 ± 3.47. Initially the larval population was less (1.48 larvae/ plant) and it was increased to 11.56 larvae/ plant at end of the crop stage (Table 14).

4.2.7 Incidence of defoliators on main and trap crop

The defoliator pest population was more on sunflower compared to groundnut at all the stages of the crop. The semiloopers population varied from 1.24 to 1.72 larvae / m row in groundnut whereas in sunflower varied from 1.64 to 4.42/ plant.

The population of S. litura and S. obliqua varied from 1.48 to 3.96 and 0.78 to 1.11 larve/ m row respectively in groundnut whereas in sunflower, the population ranged from 1.86 to 13.84 and 1.48 to 11.56 larvae/ plant (Table 15).

4.2.8 Natural enemy population in different IPM modules of groundnut

Natural enemy population was recorded in all the three IPM modules of groundnut.

4.2.8.1 Coccinellids

Coccinellid population was noticed on the crop 21 DAS to 63 DAS. Both adult and grubs were predators on sucking pests. The population both adult and grubs were ranged from 1.20 to 2.40 and 1.20 to 2.60 per m row respectively in M-I. Whereas in M-II the adult and grub population was ranged from 2.00 to 3.80 and 2.40 to 3.80 grubs per m row respectively. In M-III, the population of adult and grubs were ranged between 1.00 to 2.00 and 1.00 to 1.80 respectively (Table 16).

Paired ‘t’ value, module-II and module-I differed significantly and module-II and module-III also varied significantly from each other. Module-II was significantly superior over module-I and module III during 21 DAS to 63 DAS.

4.2.8.2 Syrphids

Syrphid population was observed on the crop from 21 DAS to 63 DAS. The population ranged between 1.40 to 2.70 syrphids / m row in first module. In second module Syrphid population was varied from 2.60 to 3.90. Whereas in third module it was differed from 1.00 to 1.80 (Table 17).

As per Paired ‘t’ value, all the three modules varied significantly from each other. Module-II was significantly superior over module-I and module-III during 21 DAS to 63 DAS. Where the module-I was significantly superior over module-III.

4.2.8.3 Campoletis chlorideae

It was observed in large proportion during August and September. The incidence was noticed on the third instar larvae of S. litura during 37 to 79 DAS. The population ranged

Table 15: Incidence of defoliators on main and trap crop

Groundnut Sunflower

Weekly interval

T. orichalcea S. litura S. obliqua T. orichalcea S. litura S. obliqua

37 DAS 1.24 1.48 0.78 2.68 1.86 1.48

44 DAS 1.64 3.48 0.82 4.42 3.64 2.86

51 DAS 1.72 2.16 0.90 2.28 5.18 4.08

58 DAS 1.68 2.80 0.95 2.46 6.28 5.48

65 DAS 1.71 2.20 0.99 1.86 9.86 7.68

72 DAS 1.56 2.00 1.09 2.06 11.06 10.06

79 DAS 1.44 1.80 1.11 1.64 13.84 11.56

DAS - days after sowing

Table 16: Natural enemy population in different IPM modules of groundnut (Coccinellids)

Coccinellid population / m row

21 DAS 28 DAS 35 DAS 42 DAS 49 DAS 56 DAS 63 DAS Treatment

Adult Grub Adult Grub Adult Grub Adult Grub Adult Grub Adult Grub Adult Grub

Module I

(Groundnut + sunflower) 1.20 1.21 1.80 1.60 2.00 2.20 2.40 2.40 2.20 2.60 1.88 2.00 1.20 1.20

Module II

(Groundnut + foxtail millet) 2.20 2.40 2.80 2.80 3.20 3.40 3.80 3.80 3.20 3.20 2.80 3.00 2.00 2.40

Module III

(Farmers’ practice) 1.00 1.10 1.40 1.20 1.16 1.12 1.60 1.60 2.00 1.80 1.04 1.40 1.20 1.00

Paired “ t” test value for comparison of means

Module I & Module II 3.16* 3.21*

3.17* 3.20* 3.21* 3.21* 6.11* 5.71* 3.16* 5.72* 3.57* 3.16* 4.00* 6.00*

Module II & Module III 6.00* 3.17* 3.50* 6.53* 8.22* 7.50* 6.53* 11.0* 3.17* 5.71* 2.86* 8.43* 4.00* 5.72*

Module III & Module I 1.00 3.50* 1.00 1.63 2.87* 5.51* 0.41 4.00* 1.00 4.02* 2.88* 3.17* 1.00 1.00

* Significant at 5% level DAS- days after sowing Module-I : Seed treatment with Trichoderma, sunflower (trap crop), pheromone trap and spraying of N. rileyi and NSKE Module-II : Seed treatment with Trichoderma, foxtail millet (intercrop), pheromone trap and spraying of Emamectin benzoate Module-III: Spraying of quinalphos

Table 17: Natural enemy population in different IPM modules of groundnut (Syrphids)

Syrphid population / m row

Treatment

21 DAS 28 DAS 35 DAS 42 DAS 49 DAS 56 DAS 63 DAS

Module I

(Groundnut + sunflower) 1.80 2.00 2.40 2.70 2.60 1.80 1.40

Module II

(Groundnut + foxtail millet) 2.60 2.80 3.60 3.90 3.20 3.00 2.60

Module III

(Farmers’ practice) 1.10 1.40 1.60 1.80 1.80 1.20 1.00

Paired “ t” test value for comparison of means

Module I & Module II 4.00* 6.00* 6.10* 6.00* 5.72* 3.20* 6.00*

Module II & Module III 6.71* 5.72* 6.32* 8.57* 5.71* 9.00* 6.35*

Module III & Module I 3.50* 2.44 4.00* 9.00* 4.00* 1.50 1.63

* Significant at 5% level DAS- days after sowing Module-I : Seed treatment with Trichoderma, sunflower (trap crop), pheromone trap and spraying of N. rileyi and NSKE Module-II : Seed treatment with Trichoderma, foxtail millet (intercrop), pheromone trap and spraying of Emamectin benzoate Module-III: Spraying of quinalphos

Table 18: Natural enemy population in different IPM modules of groundnut (Campoletis chloridae)

Campoletis chloridae population / m row

Treatment

37 DAS 44 DAS 51 DAS 58 DAS 65 DAS 72 DAS 79 DAS

Module I

(Groundnut + sunflower) 1.60 1.80 2.20 2.40 2.60 1.60 1.40

Module II

(Groundnut + foxtail millet) 2.40 2.80 3.40 3.60 3.80 2.80 2.60

Module III

(Farmers’ practice) 1.10 1.40 1.40 1.80 1.80 1.20 1.00

Paired “ t” test value for comparison of means

Module I & Module II 4.00* 6.00* 3.21* 6.00* 6.00* 6.10* 6.00*

Module II & Module III 6.50* 5.72* 6.32* 9.00* 11.00* 3.13* 6.53*

Module III & Module I 3.50* 1.63 4.00* 2.45* 4.00* 0.78 1.63

* Significant at 5% level DAS- days after sowing Module-I : Seed treatment with Trichoderma, sunflower (trap crop), pheromone trap and spraying of N. rileyi and NSKE Module-II : Seed treatment with Trichoderma, foxtail millet (intercrop), pheromone trap and spraying of Emamectin benzoate Module-III: Spraying of quinalphos

between 1.40 to 2.60/ m row in module-I. Whereas module-II the population was varied from 2.40 to 3.80 and in M-III it was differed from 1.00 to 1.80 (Table 18).

Paired ‘t’ value, module-II and module-I differed significantly and module-II and module-III also varied significantly from each other. Module-II was significantly superior over module-I and module III during 37 to 79 DAS.

4.2.9 Yield and cost economics

Among the different modules, the highest yield (39.95 q/ha) was obtained in M-II which resulted in higher gross returns (Rs. 1,07,525/ ha), net profit (Rs. 89,850/ ha) and highest C: B ratio (1:5.1) compared with net profit (Rs. 70,190/ ha), C: B ratio (1:4.3), gross returns (Rs. 86,300/ ha) and yield (30.02 q/ha) in M-I. Net profit (Rs. 33,490/ ha), C: B ratio (1:2.0), gross returns (Rs. 50,000/ha) and yield (20.00 q/ha) were least in M-III (farmer’s practice) compared to M-II and M-I (Table 18).

Table 19: Economics of IPM modules during Kharif 2009

Yield (q/ha)

Treatment

Groundnut Intercrop

Gross returns

(Rs/ ha)

Cost of cultivation

(Rs/ ha)

Net profit

(Rs/ ha)

C: B

ratio

Module I

(Groundnut + sunflower) 30.02 5.0 86,300.00 16110.00 70,190.00 1: 4.3

Module II

(Groundnut + foxtail millet) 39.95 4.5 1,07,525.00 17,675.00 89,850.00 1: 5.1

Module III

(Farmers’ practice) 20.00 - 50000.00 16,510.00 33,490.00 1: 2.0

Module-I : Seed treatment with Trichoderma, sunflower (trap crop), pheromone trap and spraying of N. rileyi and NSKE Module-II : Seed treatment with Trichoderma, foxtail millet (intercrop), pheromone trap and spraying of Emamectin benzoate Module-III: Spraying of quinalphos

5. DISCUSSION

Of more than a hundred species of insect pests associated with groundnut crop, about ten are economically important in India. Defoliators mainly tobacco caterpillar, leaf miner, Helicoverpa armigera and bihar hairy caterpillar (BHC) are gaining importance in Karnataka. At present, pest management strategies rely on chemical control. Overuse of pesticides, especially in irrigated conditions has led to the outbreak of pests such as S. litura, destruction of natural enemies, development of resistance, environmental pollution and operational hazards followed by substantial erosion in net income. Further, farmers failed to get difference in sprayed and un-sprayed plots (Ranga Rao and Wightman, 1993).This indicates the failure of insecticides sprays, which add to the total cost of production and affect the environment adversely.

As S. litura is one of the key pests of groundnut in the transitional tract of Karnataka in kharif and other irrigated places during rabi /summer, a study was envisaged to combat this noxious pest with an intention to evolve cost effective and environmentally safe approaches such as resistant cultivars, cultural practices and bio-pesticides.

Worldwide there is an increased awareness that agricultural practices must be sustainable and environmentally friendly, greater emphasis is laid on integrated management of pests of which resistant cultivars form principle component. In groundnut, the Spanish bunch cultivars are most popular in India but they are highly susceptible to pests and diseases compared to spreading type. The research efforts have been successful in identifying resistant genotypes against S. litura (Wightman et al.; 1990, Patil et al.; 1991, Dwivedi et al.; 1993, Singh et al.; 1993, Nadaf et al.; 1995, Tiwari et al.; 1989, Prasad et al.; 1998, Rame Gowda and Basavana Goud, 2002).

The present investigations were undertaken on IPM modules for groundnut pests and efforts were also made to know the nature of resistance of some selected elite genotypes of groundnut, which ultimately helps to develop strong IPM strategies. The results obtained in the light of available literature are discussed under here.

5.1 Field screening

Different groundnut genotypes were screened against S. litura under artificial infestation in the field condition during 2009, rainy season. All the elite groundnut genotypes differed significantly in per cent defoliation and larval count per mt row.

The damage ranged from 11.5 to 44.0 per cent in different genotypes. Maximum defoliation and number of larvae were observed in the JL-24 followed by GPBD-4. The genotypes viz., Mutant-III and ICGV- 86699 Tan recorded minimum damage and less number of larvae indicating their resistant nature (Fig. 1). The damage and number of larvae were moderate in GPBD-5, ICGV86699 Red and GPBD-6 (Table 1).

Present findings corroborates with the findings of Prasad and Gowda, (2006) where the damage ranged from 34.33 to 83.67 per cent in different genotypes. Maximum defoliation was observed in the Dh-40, KRG-1, JL-24 and GPBD-4 and minimum damage was recorded in Mutant-45, ICGV-91180, NC Ac- 343 and Mutant-28-2.

In screening study made by Patil et al. (1991), entries ICGV 87264 and 86598 have recorded the least damage (< 17.5%) and entries ICGV 86598 and 86125, ICGV 86350, 86276 and 87287 showed promise for resistance with less damage (< 27.5%) at two stages of screening (75 and 90 DAS).

5.1.1 Biological parameters of Spodoptera litura (F.) on selected elite groundnut genotypes

Knowledge of an insect biology on the host plant is imperative in host plant resistance investigations. Investigating developmental and biological parameters of an insect has

0

5

10

15

20

25

30

35

40

45

50

JL-24 (Susceptible

check)

ICGV-86699 Red GPBD-5 ICGV-86699 TAN GPBD-6 MUTANT -III GPBD-4

Genotypes

Per

cen

t d

efoli

ati

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0.5

1

1.5

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2.5

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3.5

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4.5

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larv

ae/

mt

row

Per cent defoliation No of larvae /mt row

Fig. 1: Performance of elite groundnut genotypes for Spodoptera litura damage during Kharif 2009

become an integral part of the process of identifying and studying pest resistance in groundnut (Prasad et al., 2000).

Groundnut genotypes such as ICGV- 86699 Tan, Mutant III, GPBD-6, GPBD-5, ICGV- 86699 Red, GPBD-4 and susceptible check (JL-24), were utilized for rearing S. litura. The effect of these genotypes on larval, pre pupal, pupal, pre oviposition, oviposition and post oviposition period, larval weight, larval mortality, per cent pupal survival ,pupal weight ,adult longevity, per cent adult emergence and fecundity of S. litura was ascertained on each of the elite genotypes. The present study demonstrated existence of substantial amount of variability in host, affecting these biological parameters.

5.1.1.1 Larval period

The length of larval duration was affected in larvae fed on foliage of test genotypes (Table 2) and there by reduces biotic potential of the pest. The genotypes Mutant III and ICGV- 86699 Tan recorded longer larval duration in each instars compare to other genotypes. While in susceptible genotypes viz., GPBD-4 and JL-24 recorded shorter larval duration (Fig. 3). The present study corroborate with the findings of Patil et al. (1995) where in S. litura had stretched larval duration on ICGV-87165, ICGV- 86350 and ICGV- 87264. Bioassay carried out with the larvae to understand the mechanism of resistance by Wightman and Ranga Rao (1994) revealed no antibiosis effect on II and IV instar larvae when fed to matured leaves of ICGV- 86031. Spodoptera frugiperda (S.) fed with resistant florunner took more days to develop compared to larvae fed with curly leaf (Todd et al., 1991). It has also been showed that longer larval duration on resistant genotypes, NC Ac -2243 (Xi Jia LI , 1987) was longer.

5.1.1.2 Larval weight and larval mortality

The genotypes Mutant III and ICGV- 86699 Tan recorded significantly low larval weight and high percentage of mortality at all the stages compared to susceptible genotypes GPBD-4 and JL-24 (Table 3 and Fig. 2). The larval per cent mortality was high on resistant genotypes in early stages compare to susceptible genotypes indicating the vulnerability of neonate larvae to the existing resistant factor. According to Stevenson et al. (1993) in pest control strategies, neonate larvae should be a primary target in host plant resistance because plant damage can be minimized if pest is eliminated as early in the life cycle as possible. The higher larval mortality of S.litura on resistant groundnut genotypes like ICGV-86031, wild tetraploid Arachis manticola was also reported by many workers (Kulkarni, 1989; Dwivedi et al., 1993; Wightman and Ranga Rao, 1994; Patil et al., 1995; Prasad and Gowda, 2006). Mortality at early stages has also been observed in Heliothis zea when reared on maize plant. The development of first stadium larvae of H. zea was retarded by the presence of chlorogenic acid and rutin in artificial diet (Isman and Duffey, 1982).

Present findings corroborates with the findings of Prasad and Gowda (2006) where in the larval weight was significantly low from larvae fed on the foliage of resistant genotypes NC Ac 343, Mutant 28-2 and R 9227. Singh and Sachan (1992) identified ICGV-86030, ICGV-86031 and NC Ac 343 as resistant to S. litura based on survival, weight gain and larval duration. The differential response of the genotypes on larval parameters indicates the possibility of antibiosis mechanisms of resistance operating in them.

The effect of resistant genotypes on larval mortality in early stage, gain in larval weight and growth of the larvae could obviously be due to chemical factors, i.e. antibiosis as elucidated by Painter (1951). The chemicals viz., querecitin glycosiden, chlorogenic acid and rutin have been reported to be the cause for resistance in wild Arachis species (Stevenson, 1993) and could be the cause for antibiosis. However, physical resistance (leaf thickness) may be also important as panitrometric studies showed that leaves of resistant wild Arachis species required a greater biting effort than did the leaves of susceptible TMV-2 and more susceptible of Arachis.

5.1.1.3 Pupal development and moth emergence

The resistant effect of Mutant III and ICGV- 86699 Tan were also observed on pupal duration, pupal weight, per cent pupal survival and moth emergence (Table 5 and 4). Similar

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60

GPBD-5 ICGV-86699 Red ICGV-86699 Tan GPBD-6 Mutant-III GPBD-4 JL-24 (Susceptible

check)

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observations were also made by Leuk and Skimmer (1971) and Garner and Lynch (1981), where pupal weight, mean percentage of pupae and moth emergence were significantly less and the pupal duration was long from larvae fed on foliages of the resistant than susceptible groundnut cultivars. Prasad and Gowda (2006) reported that the larvae fed on the resistant genotypes, NC Ac 343, Mutant 28-2, ICGV-86031 and R 9227 showed less per cent pupal survival and moth emergence compare to susceptible checks. The effect of resistance on pupal development confirms the antibiosis mechanism of resistance existing in the resistant genotypes (Painter, 1951).

5.1.1.4 Pre-oviposition, oviposition and post oviposition period

The duration of pre-oviposition, oviposition and post-oviposition were also affected in larvae fed on foliage of resistant genotypes. The genotypes Mutant III and ICGV-86699 Tan recorded longer pre-oviposition and shorter oviposition, post-oviposition period compare to susceptible genotypes GPBD-4 and JL-24 (Table 5).

5.1.1.5 Adult longevity

Adult longevity was significantly longest on susceptible genotypes JL-24 and GPBD-4 and shorter on resistant genotypes Mutant III and ICGV-86699 Tan (Table 4). The similar observations also made by Sreenivasa et al. (1997), where the development of S. litura was shortest (32.25 days)on Dh-3-30 with adult surviving maximum of 10.5 days and longest developmental period on ICGV-86031 (37.3 days) with adult surviving for maximum of 9.5 days. The effect of these genotypes on adult longevity of S. litura could obviously due to chemical factor (i.e. antibiosis).

5.1.1.6 Fecundity

The resistant effect of Mutant III and ICGV- 86699 Tan were also affected the fecundity as disclosed by total number of eggs laid by the female moths developed from larvae fed on these genotypes (Table 4 and Fig. 3). This could be an important criterion for selecting resistant genotypes. Therefore, the antibiosis effect from these genotypes could result theoretically in cumulative seasonal reduction of eggs. Painter (1951) stated that resistance at this level could be of high value as control measure.

Higher mortality of neonate larvae on Mutant III and ICGV- 86699 Tan compared to JL-24 and GPBD-4 were perhaps because of the most common and easily observable characteristics of antibiosis. Low larval and pupal weight, extension of larval, pupal, pre-oviposition, oviposition and post-oviposition period, lower fecundity, per cent pupal survival and adult emergence confirm the possible role of antibiosis as mechanism of resistance in these promising genotypes with varying degrees, as elucidated by Painter (1951).

Insect resistance in these genotypes may be due to high laminar thickness, low water content, fecundity and growth index (Tiwari et al., 1989; Dwivedi et al., 1993; Patil et al., 1995) and also due to the presence of anti- insect properties like isomers of caffeol quinic acid (Stevenson, 1993).

If these two resistant elite genotypes are agronomically superior in all characters including yielding ability. These can be recommended for cultivation in farmer’s field after evaluating on large scale farmers field or otherwise these can be utilized as resistant source in improving agronomically superior susceptible varieties of groundnut.

5.2 Evaluation of IPM modules in groundnut

In recent years groundnut has suffered heavy losses due to severe outbreak of the tobacco caterpillar, Spodoptera litura (F.). The farmers fail to adopt management practices because of high populations during monsoon rains and overlapping generations. Besides, many other sucking pests of this crop, including leafhoppers, Empoasca kerri Pruthi and thrips, Thrips palmi Karny, damage the foliage extensively. In view of environmental impact of pesticides and development of resistance to pesticides by S. litura (Rame Gowda, 1999) the

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concept of IPM has emerged that emphasizes the need for minimizing the use of pesticides and conserve the naturally occurring beneficial fauna for effective suppression of pest species. IPM modules were developed and evaluated in field at MARS Dharwad during kharif, 2009.

The two IPM modules viz., (1) IPM module, M-I comprising of GPBD-4 variety, seed treatment with Trichoderma , groundnut + sunflower as trap crop, pheromone trap (received N.rileyi spray @ 1×10

8 conidia/ml and NSKE spray @ 5% two times at 45 and 60 days after

sowing), (2) IPM module, M-II groundnut + foxtail millet, pheromone trap (received Emamectin benzoate spray @ 0.2 g/l at 45 and 60 days after sowing) compared with (3) IPM module, M-III (Farmer’s practice).

5.2.1 Monitoring the activity of S. litura

The pattern of adults trapped in pheromone traps indicates that the activity of S.litura was observed during kharif, 2009 (Appendix I). In M-I, the maximum number of adults were caught during first and second week of August and second week of September. Whereas in M-I, the maximum number of moths were caught during first week of August and second week of September.

In M-I, the maximum number of moths were caught during first two weeks of August compared to M-II. This may be due to intercropping of sunflower in M-I as it act as trap crop and attracted more moths for egg laying.

Kulkarni (1989) noticed this pest to be active throughout the year at Dharwad. But more moth catch was seen from June to October with peak moth activity during August and September. The similar observations were also made by Krishnaprasad et al. (1985) and Patel et al. (1985) are in conformity with present findings. Therefore the pheromone trap catches aid in definite predictions about adult moth activity. Which helps in initiation of management practices such as collection of egg masses in groundnut leaves and gregarious stage of early instar larvae on trap crops like sunflower and castor as well as groundnut. In case of groundnut S. litura lays eggs on upper surface of the leaves which helps in easy location of egg mass compared to other crops where it lays in lower surface including sunflower and castor.

5.2.2 Sucking pest population in different IPM modules of groundnut

The population of leafhoppers and thrips were found least under M-II followed by M-I and the highest population was recorded in M-III (Fig. 5). Low pest population in M-II may be due to the intercropping of foxtail millet where the natural enemies fauna attracted to foxtail millet for nectar and it also act as barrier for movement of thrips which is passive mover in comparison to M-III (Farmer’s practice) where no intercrops but insecticidal applications was taken up (Table 6 and 7).

Present study corroborates with other IPM modules in groundnut carried by Shambharkar et al. (2006) recorded the infestation by thrips and leaf hopper was severe at 30-45 DAS. The average percentage of damage by thrips was lower in IPM plots (15-25%) than in FP plots (20-50%). IPM modules comprising of seed treatment with Trichoderma 4 g/kg of seeds, sowing through hand dibbling, intercropping with soyabean cv. JS 335 and groundnut cv. Phule Unap at 4:1, soil amendment with 500 kg castor cake/ha, planting of castor bean as a trap crop, establishment of 10 pheromone traps/ha, and application of NSKE (5%) at 30 and 50 days after sowing (DAS) and SlNPV (1.5x10

13/ha).

The incidence of leafhoppers and thrips were lowest in IPM module compared to chemical control and farmer’s practice. The IPM module comprising of seed treatment with imidacloprid and mancozeb, interplanting of cowpea as trap crop, installation of light trap , spray with Bacillus thuringiensis and a poison bait spray with dichlorovos (Sreenivasulu et al.,2002). The similar observations were also made by Singh et al. (2005a) where the population of leafhoppers and thrips were least in IPM module compared to non- IPM module.

5.2.3 Defoliator population in three different IPM modules of groundnut

Groundnut leaf miner, tobacco caterpillar, semiloopers and Bihar hairy caterpillar population was least in M-II followed by M-I (Fig. 5). However the highest population was recorded in M-III. This is due to intercropping of foxtail millet in M-II and sunflower as trap crop in M-I (Table 8,9,10 and 11).

Singh et al. (2005b) revealed that the population of tobacco caterpillar (S. litura) and Bihar hairy caterpillar population in castor were lowest in IPM module followed by modified IPM module and the population was highest in farmer’s practice. The leaf miner (A. modicella) and tobacco caterpillar (S. litura) population was less in IPM module in comparison with non IPM module in groundnut crop (Singh et al., 2005a). Similar trend was reported by Sreenivasulu et al. (2002) and Shambharkar et al. (2006).

5.2.4 Management of Spodoptera litura in different IPM modules of groundnut

The per cent defoliation was least in M-II Followed by M-I and it was highest in M-III at 35, 50 and 65 days after sowing (Table 12).

Module III has shown significantly higher defoliation percentage followed by Module I and lowest in Module II at 45 and 65 days before spray respectively.

In first spray, 7days after spraying (DAS), Module III recoded significantly highest defoliation and larvae per mt row followed by Module I and the Module II showed less defoliation and larval population. After 15 DAS also showed the same trend i.e. significantly higher defoliation and larvae in Module III followed by Module I and lowest in Module II. In second spray, the same trend was followed at 7 DAS and 15 DAS (Table 13).

In M-II, the defoliation and larvae were least after two sprays of Emamectin benzoate. This is due to its high effectiveness. Emamectin benzoate is more effective insecticide than that of monocrotophos for S. litura. Which is a safer molecule obtained from actinomycetes.

5.2.5 Incidence of sucking and defoliating insect pests on sunflower (Trap crop).

Sucking pests such as leafhoppers, thrips, aphids and defoliators such as semiloopers, tobacco caterpillar and Bihar hairy caterpillar were noticed on the sunflower crop (Table 14). The pest population was more on sunflower compared to groundnut crop (Table 15 and Fig. 4). This is due to sunflower act as trap crop which attracted the pests more than groundnut.

Present findings are in corroborate with findings of Mahesh, (1996) reported that sunflower and castor were proved to be good trap crops and facilitated for easy collection of egg masses and larvae. Which prefer feeding on trap crop. Similar findings were made by many workers (Prasad, 1996; Anon; 2000).

5.2.6 Natural enemy population in different IPM modules of groundnut

The natural enemies such as coccinellids, syrphids and Campoletis chlorideae, the population of these natural enemies were highest in M-II followed by M-I and the population was lowest in M-III ( Farmer’s practice) (Table 16,17 and 18). This is due to intercropping of foxtail millet in M-II and sunflower in M-I, the natural enemy was high in M-II and M-I because pest population on intercrop serve as a food reservoir for adults of natural enemies and also they provided favourable microclimate for natural enemies. It is believed the natural enemy fauna also move and reduce the pest damage on main crop (Fig. 5).

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Fig. 5: Pest and natural enemy population in different IPM modules of groundnut

According to Battu (1977), recorded the occurrence of Campoletis. sp on S. litura in groundnut crop. Kulkarni (1989) reporded natural enemies of S. litura. The insect predator like Menochilus sexmaculatus and Coccinella septempunctata and ichneumonid parasitoid, Campoletis chlorideae and N. rileyi on S. litura in groundnut crop (Kulkarni and Lingappa, 2002).

5.2.7 Yield and cost economics

Among the different IPM modules, the highest yield was obtained in module-II, which resulted maximum net returns (Rs.89,850/ ha) and C: B ratio (1:5.1) followed by M-I where in net returns (Rs.70,190/ ha) and C: B ratio was (1:4.3) (Fig. 6). Net returns (Rs. 33,490/ ha) and C: B ratio (1:2.0) were low in module-III (farmer’s practice) compared to M-II and M-I due to low yield (Table 19).These results are in conformity with Singh et al. (2005a) who reported that IPM modules gave higher profit in comparison to farmer’s practices of pest control in groundnut.

M-II was an effective IPM module and best for everywhere, it comprising of foxtail millet as intercrop and insecticide Emamectin benzoate. M-I was totally bio-intensive module and it was suitable for northern transitional belt.

Future line of work

� The promising resistant genotypes viz., Mutant-III and ICGV-86699 Tan need to be evaluated for their yield potential, if they are more potential than existing verities they can be directly recommended.

� These elite genotypes can be utilized in the further resistance breeding programme.

� Module-II (groundnut + foxtail millet) should be evaluated on large scale in farmers field for management of S. litura.

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Fig. 6 : Economics of IPM modules during kharif, 2009

6. SUMMARY AND CONCLUSIONS

Investigations were carried out on the integrated pest management for defoliators on groundnut crop under both field and laboratory condition at Main Agricultural Research Station, University of Agricultural Sciences, Dharwad. The objectives of the study were 1) Screening of elite genotypes in field and to study the biology of Spodoptera litura on elite genotypes of groundnut under laboratory condition 2) Evaluation of different IPM modules of groundnut. The findings of the investigation are summarized below:

The seven groundnut genotypes were screened against S. litura resistance in the field. The genotypes viz., Mutant-III and ICGV- 86699 Tan showed 11.5 and 12.0 per cent leaf damage compared to 44.0 per cent foliar damage in susceptible check JL-24. It clearly indicates that they are highly resistant to S. litura damage.

Growth and development of an insect on elite genotypes become an important criterion in investigating mechanism of resistance. The detail investigation on biology of S. litura on all the seven genotypes further confirmed with the field screening studied by recording longest larval period (22.83 and 23.67 days), pupal period (11.67 and 11.33 days) , lowest adult longevity ( 9.67 and 9.33 days) and fecundity (379.67 and 386.00 eggs/ female) in resistant genotypes Mutant-III and ICGV- 86699 Tan respectively. Whereas susceptible check JL-24 has recorded shortest larval period (17.93 days), pupal period (9.83 days), higher adult longevity (11.83 days) and fecundity (592.00 eggs/ female).

The resistant genotypes Mutant-III and ICGV-86699 Tan recorded higher per cent larval mortality and lower larval weight at different stages of growth and development. Adult emergence, adult longevity and fecundity were affected more in these two resistant genotypes than others.

The resistant genotypes, Mutant-III and ICGV-86699 Tan were permitted the S. litura to complete its life cycle in longest period (48.92 and 49.00 days) compared to susceptible genotypes, JL-24 and GPBD-4 (41.02 and 41.00 days). The other genotypes GPBD-5, GPBD-6 and ICGV-86699 Red were intermediate. The effects of these resistant genotypes on the growth and development of S. litura could obviously be due to chemical factors i.e. antibiosis. The differential response of resistant genotypes on various components of insect growth and development could be due to different resistance factors present in these genotypes.

Evaluation of IPM modules against S. litura in groundnut crop. The population of sucking pests and defoliating pests were least in M-II (groundnut + foxtail millet) followed by M-I (groundnut + sunflower) and highest in M-III (farmer’s practice). Low pest population in M-II may be due to the intercropping of foxtail millet, where the natural enemies’ fauna attracted to foxtail millet for nectar.

The natural enemy population was high in M-II followed by M-I and it was least in M-III (farmer’s practice). The natural enemy population was high in M-II and M-I because intercrop serve as a food reservoir for adults of natural enemies and also they provided favourable microclimate for other natural enemies.

Among the different IPM modules, the highest yield was obtained in module-II, which resulted in maximum net returns (Rs.89, 850/ ha) and C: B ratio (1: 5.1) followed by M-I where in net returns (Rs.70, 190/ ha) and C: B ratio was (1: 4.3) and net returns, C: B ratio were least in M-III. It indicated that the M-II (groundnut+ foxtail millet) appeared to be effective IPM module with highest yield, net profit and C: B ratio followed by M-I (groundnut+ sunflower).

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APPENDIX

Appendix I: Pheromone trap catches of Spodoptera litura

Number of male moths per trap Pheromone trap catches of Spodoptera litura Module I Module II

05/08/2009 06/08/2009 07/08/2009 08/08/2009 09/08/2009 10/08/2009 11/08/2009 12/08/2009 13/08/2009 14/08/2009 15/08/2009 16/08/2009 17/08/2009 18/08/2009 19/08/2009 20/08/2009 21/08/2009 22/08/2009 23/08/2009 24/08/2009 25/08/2009 26/08/2009 27/08/2009 28/08/2009 29/08/2009 30/08/2009 31/08/2009 01/09/2009 02/09/2009 03/09/2009 04/09/2009 05/09/2009 06/09/2009 07/09/2009 08/09/2009 09/09/2009 10/09/2009 11/09/2009 12/09/2009 13/09/2009 14/09/2009 15/09/2009 16/09/2009 17/09/2009 18/09/2009 19/09/2009 20/09/2009 21/09/2009 22/09/2009 23/09/2009 24/09/2009 25/09/2009 26/09/2009 27/09/2009 28/09/2009 29/09/2009 30/09/2009

121 198 199 358 373 432 451 135 114 202 112 029 032 013 040 062 060 027 031 019 035 047 031 027 050 039 021 019 031 028 021 018 023 031 028 061 053 029 040 034 075 035 039 015 028 031 027 062 052 034 028 019 021 037 021 027 018

022 024 040 036 110 032 130 147 095 096 075 021 029 069 159 029 027 018 050 024 031 030 028 031 058 024 032 024 029 034 013 031 020 019 031 048 044 063 057 061 112 027 024 026 069 050 018 036 058 037 031 024 049 040 032 046 034

SCREENING ELITE GENOTYPES AND IPM OF

DEFOLIATORS IN GROUNDNUT

RASHMI S. YAMBHATANL 2010 Dr.R.K. PATIL Major Advisor

ABSTRACT

Screening elite genotypes and IPM of defoliators in groundnut were studied during Kharif 2009, at Main Agricultural Research Station, UAS, Dharwad. The seven groundnut genotypes were screened for Spodoptera litura (F.) resistance in the field. The genotypes viz., Mutant-III and ICGV-86699 Tan showed 11.5 and 12.0 per cent leaf damage compared to 44.0 per cent foliar damage in susceptible check, JL-24.

The detailed investigation on biology of S. litura on these seven genotypes further confirmed with the field screening studied by recording longest larval period (22.83 and 23.67 days), pupal period (11.67 and 11.33 days), lowest adult longevity (9.67 and 9.33 days) and fecundity (379.67 and 386.0 eggs/ female) in Mutant-III and ICGV-86699 Tan respectively. Whereas susceptible check, JL-24 has recorded shortest larval period (17.93 days), pupal period (9.83 days), higher adult longevity (11.83 days) and fecundity (592.0 eggs/ female). The resistant genotypes, Mutant-III and ICGV-86699 Tan permitted S. litura to complete its life cycle in longest period (48.92 and 49.00 days respectively) compared to susceptible varieties, JL-24 and GPBD-4 (41.02 and 41.00 days respectively). The other genotypes GPBD-5, GPBD-6 and ICGV-86699 Red were intermediate. The effects of these resistant genotypes on the growth and development of S. litura could obviously be due to chemical factor i.e. antibiosis.

Among different IPM modules, Module-II proved as effective IPM module in reducing defoliator population, enhancing natural enemy population and recording higher yield (39.95 q/ha) with maximum net returns (Rs.89,850/ha) and highest C:B ratio (1:5.1) followed by Module-I. Module-II comprising of foxtail millet as intercrop (7:1) and insecticide Emamectin benzoate (0.2 ml/lit) and M-I was totally bio-intensive module and it comprising of sunflower as trap crop and Nomuraea rileyi spray and it was suitable for northern transitional belt.