predacious mites (acarina: phytoseiidae) on sprayed apple trees at bathurst (n.s.w.)

3
J. Aust. mt. Soc.. 1975, 14: 217-219 217 PREDACIOUS MITES (ACARINA: PHYTOSEIIDAE) ON SPRAYED APPLE TREES AT BATHURST (N.S.W.) E. SCHICHA Agricultural Research Station, Department of Agriculture, Bathurst, N.S. W . 2795. Abstract Five pi-cdacious mite species of the family Phytoseiidae were found on leaves and spurs of apple trees (cv. Granny Smith) at Bathurst during the 1971-72 season: Amblyseius lentiginosus Denmark and Schicha (closely resembling A. rhuhthrs Denmark), Phytosrius jutheringhumiae Denmark and Schicha (closely resembling P. mucropilis (Banks) and P. woodhurvi De Leon), T’phlodromirs helenae Schicha and Dose (closely resembling T. pyri Scheuten), TyphlotL.ur~ius ncshitti Womersley, and Amb1.vseius sp. The species were detected only between late February and April after a pesticide spraying programme incorporating ryania, captan and dinocap had ceased. Adults of all phytoseiid mites were observed feeding on all developmental stages of Tetranychus urticae (Koch) (Tetranychidae). Introduction Phytoseiid mites are prominent in the arthropod fauna of unsprayed apple trees in many countries and can be valuable predators of leaf feeding mites (Huffaker et al. 1970). In a previous study at Bathurst Geier et al. (1969) found that phytoseiid mites and Stethorus spp beetles were associated with a noticeable fall in the pest status of Tetranychus urticae (Koch) during a 3 year period when all insecticides except ryania were withheld. Further studies in Australian apple orchards have confirmed that Stetharus spp are important predators of T . urticae (Readshaw 1971). The present investigation was conducted to record the occurrence, distribution, and feeding behaviour of phytoseiid mite species on apple trees during and after a ryania-captan-dinocap spray programme. Materials and methods On every sampling date 30 leaves and 30 spurs (3 cm long, 0.5 cm thick, rough bark) were collected from each of 5 mature Granny Smith apple trees selected from the block of trees at Bathurst Agricultural Research Station studied by Geier et al. in 1969. The leaves were sampled at random from the middle section of each of the trees and examined with a stereomicroscope. From 1966 to 1969, when these trees were used for pest management studies (Geier et al. 1969, Lloyd et al. 1970), pesticide treatment was restricted to the natural insecticide ryania and the fungicide captan. In 1966-67 dinocap (Karathane) was applied also. By spring 1969 the trees supported many phytoseiid mites. During the following 3 growing seasons, including that of the present investigation ( 1971-72), a mixture of 0.67; ryania and 0.1% captan was sprayed on several occasions in spring together with either 1 or 2 applications of 0.02 OO dinocap in late spring or summer. Other treatments included a 0.1 3,) DDT spray in early spring 1969 to control plague thrips (Thrips im~iginis Bagnall), mineral oil in the winter of 1971 for control of San Jose scale ( Quarirrispidiotus perniciosus (Comstock)) and copper oxychloride (Cuprox) as a fungicide in September 1971. The spray programme during 1971-1972 is shown in Fig. 1. Results and discussion Five phytoseiid mite species including 3 new species were found on the apple trees. Characteristic morphological features enabled the larvae, nymphs and adults of Phytoseius fotheringharniae, which resembles closely P. macropilis (Banks) and P. rvoodburyi De Leon, and of Arnblyseius lentiginosus, which is closely related to A. rh~htlus Denmark, to be readily distinguishable at 20 to 50 times magnification. These species have been described by Denmark and Schicha (1974a, 1974b). The other 3 species. T,.phlodromus Iieirnue Schicha and Dosse, which is closely related to T. pyri Scheuten, Typhlodromus riesbitti Womersley and Arnblyseius sp. could only be

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Page 1: PREDACIOUS MITES (ACARINA: PHYTOSEIIDAE) ON SPRAYED APPLE TREES AT BATHURST (N.S.W.)

J . Aust. m t . Soc.. 1975, 14: 217-219 217

PREDACIOUS MITES (ACARINA: PHYTOSEIIDAE) ON SPRAYED APPLE TREES AT BATHURST (N.S.W.)

E. SCHICHA Agricultural Research Station, Department of Agriculture, Bathurst, N.S. W . 2795.

Abstract Five pi-cdacious mite species of the family Phytoseiidae were found on leaves and spurs of apple trees

(cv. Granny Smith) at Bathurst during the 1971-72 season: Amblyseius lentiginosus Denmark and Schicha (closely resembling A . rhuhthrs Denmark), Phytosrius jutheringhumiae Denmark and Schicha (closely resembling P. mucropilis (Banks) and P. woodhurvi De Leon), T’phlodromirs helenae Schicha and Dose (closely resembling T. pyri Scheuten), TyphlotL.ur~ius ncshitti Womersley, and Amb1.vseius sp. The species were detected only between late February and April after a pesticide spraying programme incorporating ryania, captan and dinocap had ceased. Adults of all phytoseiid mites were observed feeding on all developmental stages of Tetranychus urticae (Koch) (Tetranychidae).

Introduction Phytoseiid mites are prominent in the arthropod fauna of unsprayed apple trees in

many countries and can be valuable predators of leaf feeding mites (Huffaker et al. 1970). In a previous study at Bathurst Geier et al. (1969) found that phytoseiid mites and Stethorus spp beetles were associated with a noticeable fall in the pest status of Tetranychus urticae (Koch) during a 3 year period when all insecticides except ryania were withheld. Further studies in Australian apple orchards have confirmed that Stetharus spp are important predators of T . urticae (Readshaw 1971).

The present investigation was conducted to record the occurrence, distribution, and feeding behaviour of phytoseiid mite species on apple trees during and after a ryania-captan-dinocap spray programme.

Materials and methods On every sampling date 30 leaves and 30 spurs (3 cm long, 0.5 cm thick, rough

bark) were collected from each of 5 mature Granny Smith apple trees selected from the block of trees at Bathurst Agricultural Research Station studied by Geier et al. in 1969. The leaves were sampled at random from the middle section of each of the trees and examined with a stereomicroscope.

From 1966 to 1969, when these trees were used for pest management studies (Geier et al. 1969, Lloyd et al. 1970), pesticide treatment was restricted to the natural insecticide ryania and the fungicide captan. In 1966-67 dinocap (Karathane) was applied also. By spring 1969 the trees supported many phytoseiid mites. During the following 3 growing seasons, including that of the present investigation ( 1971-72), a mixture of 0.67; ryania and 0.1% captan was sprayed on several occasions in spring together with either 1 or 2 applications of 0.02 O O dinocap in late spring or summer. Other treatments included a 0.1 3,) DDT spray in early spring 1969 to control plague thrips (Thrips im~iginis Bagnall), mineral oil in the winter of 1971 for control of San Jose scale ( Quarirrispidiotus perniciosus (Comstock)) and copper oxychloride (Cuprox) as a fungicide in September 1971. The spray programme during 1971-1972 is shown in Fig. 1.

Results and discussion Five phytoseiid mite species including 3 new species were found on the apple trees.

Characteristic morphological features enabled the larvae, nymphs and adults of Phytoseius fotheringharniae, which resembles closely P. macropilis (Banks) and P. rvoodburyi De Leon, and of Arnblyseius lentiginosus, which is closely related to A. rh~htlus Denmark, to be readily distinguishable at 20 to 50 times magnification. These species have been described by Denmark and Schicha (1974a, 1974b). The other 3 species. T,.phlodromus Iieirnue Schicha and Dosse, which is closely related to T. pyri Scheuten, Typhlodromus riesbitti Womersley and Arnblyseius sp. could only be

Page 2: PREDACIOUS MITES (ACARINA: PHYTOSEIIDAE) ON SPRAYED APPLE TREES AT BATHURST (N.S.W.)

218 E. SCHICHA

TABLE 1

DISTRIBUTION AT MAXIMUM ABUNDANCE OF ADULTS OF FIVE PHYTOSEIID MITE SPECIES PER 150 LEAVES OR 150 SPURS ON SPRAYED APPLE TREES

AT BATHURST IN 1971-72

50 -

-

-

20 -

10 -

0

Species Leaves Spurs

Amblyseius lentiginosus (males and females) + + ++

Czcap tan 0.18 Dmdinocap 0.02%

R = ryania 0.6V0

N A A = &-naphthalene acet ic acid 20ppm

e no phytoseiid mites found p /,/. c c c c c c c /'

NAA R R R R D D I' / /' /.

/. ,,/. ' , . ~ , ~ ~ ~ ~ , ~ ~ ~ ~ ~ ~ ~ , ~ ~ . ~ ~ . ~ . ~ . ~ ~

I I I I

Ambl.vseius sp. (females)

+ + + +

Typhlodromus helenae (males and females)

+ + + tt

Typhlodromus nesbitti -

(females) +

Phytoseius fotheringhamiae + ~

(males and females)

+++abundant (20-loo), + +noticeable (5-20), +scarce (0-5), -not detected.

dstinguished from each other, and identified, at 800 to 1000 magnification. The distribution of the phytoseiids is shown in Table 1.

The change in the number of mites during 1971-1972 is shown in Fig. 1. Although searches for phytoseiid mites were commenced in October, none was detected in the samples until late February when the fruit was becoming mature. Populations of the 5

0 W

W -I

0 In

a: w

2

7

a cn W k 2

3 3 n < u. 0 a: W m 3 3 Z

total number of Phytoseiidae

Ty p h lod ro m u s he I en a e

Amblyseius lent iginosus

Phytoseius fotheringhamiae

Amblyseius sp. [ I

FIG. 1.-The abundance of phytoseiid mites on leaves of Granny Smith apple trees at Bathurst (N.S.W.) in the 1971-72 growing season during and after a spraying programme including captan, dinocap, ryania, and a-naphthalene acetic acid; x = sampling dates.

Page 3: PREDACIOUS MITES (ACARINA: PHYTOSEIIDAE) ON SPRAYED APPLE TREES AT BATHURST (N.S.W.)

PREDACIOUS MITES ON SPRAYED APPLE TREES 219

species increased in March and April with T. helenae quickly becoming predominant on leaves. A. lentiginosus also became numerous on leaves, and on spurs, in the same period.

Of the other phytoseiid mites, P. fotheringhamiae was scarce on leaves and absent from spurs. Only females of Amblyseius sp. could be found although by late April, when the fruit was ready for harvest, they were present in large numbers on spurs. Very few Typhlodromus nesbitti females were found.

Adults of all species were observed feeding on all developmental stages of T. urticae. Hence it seems possible that all these phytoseiids could contribute to the control of T. urticae in the field, but their relative importance was not determined.

One feature of the results was the apparent absence of phytoseiid mites during the period when the pesticide spray programme was in operation. In other countries, field and laboratory tests have indicated that ryania and captan seem to be relatively harmless to phytoseiid mites of apple trees and other crops (Clancy and McAlister 1956 a, 1956 b; Bartlett 1964; Oatman 1965,1966). However, dinocap is known to be toxic to phytoseiid mites (Downing 1966; Dabrowski 1968), and it seems likely that this was the case in the present investigation.

References BARTLETT, B. R. (1964).-The toxicity of some pesticide residues to adult Amblyseius hibisci, with a

compilation of the effects of pesticides upon phytoseiid mites. J. econ. Ent. 57: 559-63. CLANCY, D. W. and MCALISTER, H. J. (1956, a).-selectivep pesticides as aids to biologicalcontrol oforchard

pests. J. econ. Enr. 4 9 196-202. CLANCY, D. W. and MCALISTER, H. J. (1956. b). -Effects of spray practices on apple mites and their

predators in West Virginia. Proc. IOr l r inr. Congr. Ent. Montreal 4: 597-601. DABROWSKI, Z. T. (1968).-Badania nad toksycznoscia pestycydow stosowanych w sadach w Polsce dla

roztoczy drapieznych (Phytoseiidae). Roc x. I ’ r d r u h . 93(A): 655-670. DENMARK, H. A. and SCHICHA, E.-A new species of Aurblyseius Berlese (Acarina: Phytoseiidae) from

apple in Australia. Proc. Linn. Soc. N.S. W. 99: 145-150. DENMARK, H. A. and SCHICHA, E.-A new species of Phyfoseius Ribaga (Acarina: Phytoseiidae) from

apple in Australia. Proc. Linn. SOC. N.S.W. 99: 177-180. DOWNING, R. S. (1966).-The effect of certain miticides on the predacious mite Neoseiulus caudiglans

(Acarina: Phytoseiidae) Can. J. PI. Sci. 46: 521-524. GEIER, P. W., HARRIS, W. G., HILLMAN, T. J., HUDSON, N. M., JONES, E. L., LLOYD, N. C., LOWER, H. F.,

MORRIS, D. S., and WEBSTER, W. J., (1969).-A co-operative programme of research into the management of pest insects in pome-fruit orchards in southeastern Australia. Progress Report for 1966-67. CSIRO, Melbourne.

HUFFAKER, C. B., VAN DEVRIE, M., and MCMURTRY, J. A. (1970).-&ologyoftetranychid mitesand their natural enemies: a review. 11. Tetranychid populations and their possible control by predators; an evaluation. Hilgardia 4 0 391-458.

LLOYD, N. C., JONES, E. L., MoRRIs.D.S., WEESTER, W. J., HARRIS, W. B.,LowER,H. F., HUDSON, N. M., and GEIER, P. W. (1970).-Managing apple pests: a new perspective. J. Aust. Inst. agric. Sci. 36: 2s 1 - 3 8 ,

OATMAN, E. R. (1965).-Effects of preblossom miticides and subsequent insecticide application on mite populations on apple in Wisconsin. J. econ. Ent. 58: 335-343.

OATMAN, E. R. (1966).-Studies on integrated control of apple pests. J. econ. Ent. 5% 368-373. READSHAW, J. L. (1971).-An ecological approach to the control of mites in Australian orchards. J. Aust.

ins^ agric. Sci 37: 226-230. SCHICHA, E. and DOSSE. G. (1974).-A new species of Typhlodromus Scheuten (Acarina: Phytoseiidae) from

apple in Australia. Proc. Linn. SOC. N.S.W. 99: 79-84.

[Manuscript received September 23, 19741