insect management and pesticide...

1 | OS U - H A RE C - I A E P ( R o n d o n ’ s P ro g r a m )

Silvia I. Rondon Associate Professor, Extension Entomologist Specialist

Oregon State University Hermiston Agricultural Research and Extension Center

Irrigated Agricultural Entomology Program

2121 South First Street Hermiston, Oregon 97838

Email: [email protected] Phone: (541) 567-8321 ext 108

Cell phone: (541) 314-3181

Insect Management and Pesticide Evaluations

2012

mailto:[email protected]


Chemicals are not being endorsed by Oregon State University. If some of the products presented in this report are not yet registered for the uses discussed herein their use outside of an experimental context is therefore illegal Acknowledgements Special thanks to Alexzandra F. Murphy, Post-doctoral scholar, OSU-HAREC-IAEP for statistical analysis Faculty Research Assistant: Ruben Marchosky, OSU-HAREC-IAEP for field setting and organization of the crew Plots preparation and establishment: Tim Weinke and Phil Rogers, OSU-HAREC Student assistants: OSU-HAREC-IAEP Tanner Keys, Mary Adams, Dale Wilkerson, Jonathan Macias, Brandy White, Treve Moffit, Abbye McDonough Cooperating company Nap-Chem Brandt Monterrey MGK BASF RMS Bayer Chemtura UPI Syngenta Chemtura Nichino


Potato psyllids control Zebra chip (ZC) is a destructive disease of potatoes emerging in North America and other parts of the world. Zebra Chip was first recorded in the Columbia Basin of Washington and Oregon late in the 2011 growing season. This area produces more than 50% of the potatoes grown in the United States, so the presence of ZC in the region has the potential to be economically devastating. The pathogen associated with ZC is the bacterium Candidatus Liberibacter solanacearum (a.k.a. Ca. L. psyllaurous), vectored to potato by the potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Triozidae). In potatoes, the bacterium affects the phloem tissue, causing foliar and tuber symptoms. Because these insects are so small, damage to potatoes frequently occurs before the problem is detected. A number of chemical control options are available for potato psyllids control but this is the first year that pesticides are being tested in the field in Oregon. More information can be found at http://ir.library.oewgonstate.edu/xmlui/bitstream/handle/1957/30058/pnw633.pedf

http://ir.library.oewgonstate.edu/xmlui/bitstream/handle/1957/30058/pnw633.pedf


Efficacy of selected organic pesticides on potato psyllid control-Part I Objectives To compare the efficacy of selected registered and experimental pesticides against the potato psyllid in Oregon Plots information Study location OSU-HAREC-IAEP, Hermiston, Oregon Planting date 19 May 2012 Variety Russet Rangers Application dates Two applications were made seven days apart on 25 July 2012 and 2 August 2012. Environmental conditions at application Temperature 54.15-92.7070F (7/25); 62.52-89.200F (8/2); full sun, winds calm. Application equipment Foliar applications were applied with a tractor-mounted boom sprayer using AI11002VS nozzles spaced at 20” at 30 psi and a ground speed of 2.5 mph. Chemigation treatment was applied with a tractor-drawn chemigation simulator. All insecticides were applied in 0.10 acre inch of water. Plot characteristics Plots were 4-rows wide × 30 feet long. The experimental design was a randomized complete block with 4 replications per treatment. Normal commercial production practices were followed throughout the season. Fertilizer 20 March 2012 Pre-plant fertilizer -63N-300P-200K-20S-5Zn-1B 4 June 2012 30 N 11 June 2012 30 N 18 June 2012 30 N 25 June 2012 30 N 2 July 2012 30 N 9 July 2012 40N Herbicides


12 June 2012 Dithane -1 lb 20 June 2012 Echo - 1.5 pts 25 June 2012 Dithane -1.5 pts 4 July 2012 Echo - 1.5 pts 10 July 2012 Dithane -1.5 pts 17 July 2012 Echo - 1.5 pts 24 July 2012 Dithane -1.5 pts 31 July 2012 Echo - 1.5 pts 7 August 2012 Dithane -1.5 pts 14 August 2012 Echo - 1.5 pts Treatments All treatments for foliar application and chemigation are shown in Table 1. Methods Sampling started after plant emergence (4 June 2012). Un-baited yellow sticky cards and DVAC (inverted leaf blower) were used to detect the first occurrence of psyllid adults in the research plots. Sampling occurred only in the two center rows targeting the middle to the bottom of the plants. Also, 10 leaves from the center and bottom part of the plants from the central two rows were sampled. DVAC was used to sample adults, while leaves were sampled to look for psyllid eggs or nymphs. No action threshold exists for psyllids in potato, thus the action threshold was detection of potato psyllids at any life stage. As season progressed, and plants started showing typical ZC symptoms, plants were selected for PCR analysis to confirm the disease (Crosslin, JM., H Lin, JE Munyaneza. 2011. Detection of “Candidatus Liberibacter solanacearum” in the potato psyllid by conventional and real-time PCR. Southwestern Entomologist 36(2): 125-135). Data analyses Data were analyzed by using a randomized block ANOVA of arthropod densities followed by Tukey’s multiple comparisons (p < 0.05). All data was transformed using Box-Cox or Johnson transformations prior to analysis because normality assumptions were not satisfied with the original data. If data failed to meet the necessary assumptions, a Kruskal-Wallis was used as an alternative to ANOVA. Samples of adults (DVAC samples) or nymphs and eggs (leaf samples) were analyzed separately. Each sampling date, following insecticide treatments, was also analyzed separately. The mean psyllid numbers for Azera foliar and Azera chemigation from 1, 8 and 15 August were pooled and compared as appropriate using a two-sample t-test after transformation with a Box-Cox transformation. If normality assumptions were not met a Mann-Whitney was used in place of a t-test. Comparisons were made for adults, nymphs, eggs, and total psyllids. All analyses were performed using Minitab 16.2.1. Results and discussion No phytotoxicity was noted. Seasonal trends


Potato psyllid populations increased as the season progressed, with the highest populations building toward the end of the season (Fig. 1). Seven days after first application (1 August) The results for psyllid adults, nymphs, and eggs seven days after first application are shown in Table 2. Mean number of adult psyllids, nymphs and eggs were not significantly different among treatments a week after application. Numbers of adults were greater than nymphs and eggs at this time of the season. The greatest difference was observed analyzing the adult data. The lowest numbers of psyllid adults were observed in the Agri-Trap and Azera foliar treatments. The greatest numbers of adults compared to the control were observed in the Azera chemigation treatment, followed by the Fast Trac EC treatment. The lowest numbers of psyllid nymphs were observed in the Pyganic + Tri-Tek oil, Fast Trac EC and the standard Leverage. The greatest numbers of nymphs compared to the control were observed in the Agri-trap treatment. Seven days after second application (8 August) The results for psyllid adults, nymphs, and eggs seven days after second application are shown in Table 3. There were no significant differences among treatments for psyllid adults, nymphs, or eggs. However, mean adult psyllids were lowest in the Agri-Trap treatment when compared to the control. The lowest mean numbers of nymphs were observed in the Fast Trac EC and Leverage treatments when compared to the control. The highest mean number of eggs was observed in the Azera chemigation treatment, even though this treatment had lower numbers of nymphs. Numbers of potato psyllids eggs on this trial were too low for statistical comparisons. Fourteen days after second application (15 August) The results for psyllid adults, nymphs, and eggs fourteen days after second application are shown in Table 4. There were no significant differences between treatments for psyllid adults nymphs, or eggs. However, the mean number of adult psyllids was low in the Azera foliar treatment, followed by the Azera chemigation treatment. Pyganic + Tri-Tek oil and Azera chemigation had the lowest (zero) psyllid nymphs compared to the control while Azera foliar had the highest nymph counts. Egg counts in the Pyganic + Tri-Tec oil, Leverage and Azera chemigation treatments were relatively low compared to the other treatments. The highest number of eggs was observed in the Agri-trap treatment. Foliar and Chemigation application of Azera There were no significant differences between application methods based on psyllid adults, nymphs, eggs or total psyllids. However, there was almost a tenfold difference between the mean number of potato psyllid nymphs found in foliar applications compared to chemigation. Conclusions

Psyllids in the entire region increased as season progressed.

In experimental plots, high number of psyllids (adults, nymphs and eggs) was present in control plots by the end of the season. Less than 1% were positive for Liberibacter.


Growers in the region were proactively spraying fields to control psyllids throughout the season. It was decided to terminate plots when psyllid counts in control plots were high. This decision was reached in order to reduce the risk of psyllid infestation in the area.

Although there were no significant differences among treatments seven days after first treatment, low mean numbers of potato psyllid adults were observed in the Agri-Trap and Azera foliar treatment as compared to the other treatments. After a second application, Agri-Trap lost its residual effect. After fourteen days of application, only the Azera treatment had a slightly better residual effect.

Azera, which is reported to have multiple modes of action (contact, ingestion and IGR), should have had a positive effect on all instars of the potato psyllid. However, the foliar treatment of Azera performed better than the chemigation treatment, controlling adults; control of potato psyllid eggs and nymphs was inconsistent. The foliar application appeared to be more effective than using chemigation controlling adults and eggs but no for nymphs. This experiment should be repeated. Growers in the area rely on chemigation applications and this data is surprising.

Agri-Trap, responded well controlling nymphs fourteen days after application and a second application did positively reduce potato psyllid nymphs in the treatment plots. Agri-Trap did show some activity against adults seven days after treatment, but did not hold out well at fourteen days. There were some difficulties mixing and handling the product because precipitation issues.

Pyganic + Tri-Tec oil, a contact insecticide, reduced the number of potato psyllid eggs and nymphs in treatment plots fourteen days after treatment. It did not appear to have an effect on adults.

Leverage controlled adults better at fourteen days after treatment than at seven days after treatment. This data was consistent with other trials where Leverage was used as a standard. A second application was needed to control adults. On the other hand, Leverage showed great potato psyllid nymph and egg control.

Fast Trac did not appear to have an effect on psyllid adults, nymphs or eggs as the mean numbers were consistently higher than the control.

Conclusions Some of the insecticides tested proved to have a good activity against potato psyllid in the adult and/or immature stages. Although this was an efficacy trial, this preliminary data suggest promising “Old” and new chemistry against this pests. Al least one more year data is needed to make conclusive recommendations in favor or against any of these products.


Table 1. List of treatments, rate, mode of application and total area sprayed.

Treatment #

Product Rate (fl oz/a)

Mode of Application

Total area sprayed (acres)

1 Untreated Control - - - 2 Pyganic Acid

Tri-Tek oil 18

64 fl oz/100 gal Foliar/ground

(tank mix) 0.0312213

3 FastTrac EC 1.4 Foliar/ground 0.0312213 4 Leverage 360 2.80 Foliar/ground 0.0312213 5 Agri-Trap 33 Foliar/ground 0.0312213 6 Azera 32 Foliar/ground 0.0312213 7 Azera 32 Chemigation 0.0312213

Table 2. Mean potato psyllid (±SE) counts seven days after first application of foliar insecticides, Hermiston, Oregon 2012.*

Treatment Adults Nymphs Eggs

Untreated Control 0.00 ± 0.00a 0.00 ± 0.00a 0.00 ± 0.00a

Pyganic + Tri-Tek oil 0.25 ± 0.25a 0.00 ± 0.00a 1.00 ± 0.71a

Fast Trac EC 0.50 ± 0.29a 0.00 ± 0.00a 0.00 ± 0.00a

Leverage 360 0.25 ± 0.25a 0.00 ± 0.00a 0.00 ± 0.00a

Agri-trap 0.00 ± 0.00a 1.00 ± 1.00a 0.00 ± 0.00a

Azera Foliar 0.00 ± 0.00a 0.25 ± 0.25a 0.00 ± 0.00a

Azera Chemigation 0.75 ± 0.48a 0.25 ± 0.25a 0.00 ± 0.00a *Adults were sampled with a DVAC and nymphs and eggs were sampled collecting leaves. Means within the same column that share the same letter are not significantly different.


Table 3. Mean potato psyllid (±SE) counts seven days after the second application of foliar insecticides, Hermiston, OR 2012.*




Fast Trac EC 1.25 ± 0.95a 0.00 ± 0.00a 0.00 ± 0.00a

Leverage 360 2.25 ± 1.11a 0.00 ± 0.00a 0.00 ± 0.00a

Agri-trap 0.75 ± 0.25a 0.75 ± 0.75a 0.25 ± 0.25a

Azera Foliar 1.50 ± 0.87a 1.00 ± 0.58a 0.00 ± 0.00a


Table 4. Mean potato psyllid (±SE) counts fourteen days after the second application of foliar insecticides*, Hermiston, OR 2012.*




Fast Trac EC 7.00 ± 1.68a 0.75 ± 0.48a 3.75 ± 2.17a

Leverage 360 7.00 ± 2.12a 0.50 ± 0.29a 0.50 ± 0.29a

Agri-trap 6.00 ± 2.04a 0.25 ± 0.25a 4.25 ± 4.25a

Azera Foliar 2.75 ± 0.48a 2.75 ± 2.14a 1.25 ± 0.75a


1 0 | OS U - H A RE C - I A E P ( R o n d o n ’ s P ro g r a m )

Efficacy of selected pesticides on potato psyllid control-Part II Objectives To compare the efficacy of selected registered and experimental pesticides against the potato psyllid in Oregon. Plots information (same as in Part I) Treatments All treatments received Maxim®4FS in furrow at planting at a rate of 0.08 fl oz/100lbs seed (Table 1). Maxim®4FS seed treatment fungicide has become the standard in early-season disease protection against key plant pathogens, including Fusarium and Rhizoctonia. Methods Sampling started after plant emergence (4 June 2012). Un-baited yellow sticky cards and DVAC (inverted leaf blower) were used to detect the first occurrence of psyllid adults in the research plots. Sampling occurred only in the two center rows targeting the middle to the bottom of the plants. Also, 10 leaves from the center and bottom part of the plants from the central two rows were sampled. DVAC was used to sample adults, while leaves were sampled to look for psyllid eggs or nymphs. No action threshold exists for psyllids in potato, thus the action threshold was detection of potato psyllids at any life stage. As season progressed, and plants started showing typical ZC symptoms, plants were selected for PCR analysis to confirm the disease (Crosslin, JM., H. Lin, JE Munyaneza. 2011. Detection of “Candidatus Liberibacter solanacearum” in the potato psyllid by conventional and real-time PCR. Southwestern Entomologist 36(2): 125-135). Data Analyses Analyses were performed using randomized block ANOVA of arthropod densities and Least Significant Differences (LSD) Multiple Range Test (p < 0.05). Samples of adults (DVAC samples) or nymphs and eggs (leaf samples) were analyzed separately. Each sampling date, following insecticide treatments, was also analyzed separately. All analyses were performed using JMP 10. Results No phytotoxicity was noted. Seven days after first application (30 July) The results for psyllid adults, nymphs, and eggs seven days after first application are shown in Table 2. Mean number of psyllids and nymphs were not significantly different among treatments. Numbers of nymphs were greater than adults and eggs at this time of the season and the greatest difference was observed analyzing the nymph data. The lowest number of psyllid nymphs per sample compared to the control was observed in the Sivanto treatment, followed by Movento, Rimon, Assail 1.1 oz and Assail 1.7 oz. There were significant differences among treatments for psyllid eggs. A significantly greater number of eggs compared to the


control were observed in the Rimon treatment; all other treatments were statistically similar to the control. Fourteen days after first application (6 August) The results for psyllid adults, nymphs, and eggs fourteen days after first application are shown in Table 3. There were no significant differences among treatments for psyllid adults, nymphs, or eggs. However, mean adult psyllids were lower in the Movento, Sivanto and Rimon treatments. The lowest mean number of nymphs were observed in the Leverage and Sivanto treatments when compared to the control. Seven days after second treatment (13 August) The results for psyllid adults, nymphs, and eggs seven days after second treatment are shown in Table 4. There were no significant differences between treatments for psyllid adults or eggs. However, the mean number of adult psyllids was low in the Movento treatment. Movento and Leverage had the lowest (zero) psyllid eggs compared to the control. There were significant differences for the mean number of psyllid nymphs per sample. Nymph counts in the Movento, Leverage and Sivanto treatments were low compared to the control. The highest number of nymphs was observed in the Assail (1.7oz) treatments. No further data was collected beyond this point since psyllid numbers were increasing tremendously in the experimental plots and there were concerns about the spread of the issue in the region. Experimental plots for this efficacy trial were immediately terminated. Discussion


In experimental plots, high number of psyllids (adults, nymphs and eggs) was present in control plots. Less than 1% of psyllids tested were positive for Liberibacter however, at least 20% percentage of plants in control plots showed classic ZC. Few tubers rated on this trial (Texas 1-3- scale) confirmed this observation. Growers in the region were proactively spraying fields to control psyllids throughout the season. It was decided to terminate plots when psyllid counts in control plots were high. This decision was reached in order to reduce the risk of psyllid infestation in the area.

Although there were no significant differences among treatments seven days after first treatment, low mean numbers of potato psyllid nymphs were observed in the Sivanto treatment as compared to the other treatments. Low mean numbers of potato psyllid nymphs in the Rimon, Movento, Assail (low and high) rate treatments were also observed.

The residual effect of Sivanto, Rimon, Movento and Leverage treatments on nymphs was observed at fourteen days after first application.

Sivanto, that affects the insect central nervous system, performed well controlling nymphs seven and fourteen days after first application. It also performed well controlling adults. Results of the application of Movento were comparable to the results of the Sivanto treatment for controling adults.


Rimon responded well controlling nymphs seven days after application. It did not hold out well beyond fourteen days after application. A second application at fourteen day did positively reduce potato psyllid nymphs in the treatment plots. Since Rimon acts by inhibiting chitin formation, it was not expected to affect adults. Table 3 shows the positive effect of Rimon controlling psyllid eggs.

Oberon, an insecticide/miticide, reduced the number of potato psyllid eggs and nymphs in treatment plots fourteen days after treatment. As expected, it did not have an effect on adults.

Leverage, controlled adults at seven days after treatment better than at fourteen days after treatment. A second application was needed to control adults. On the other hand, Leverage showed great potato psyllid nymph and egg control only after the second application.

Assail, a systemic and translaminar neonicotinoid, treats both the leaf surface and the underside of the leaf, and should have had a good effect on psyllids, however, performed best controlling nymphs fourteen days after treatment at a lower rate. Assail at a higher rate (1.7oz) was outperformed by Assail at a lower rate (1.10oz).

Conclusions Some of the insecticides tested proved to have good activity against potato psyllids in the adult and/or immature stages. Although this was an efficacy trial, this preliminary data suggest promising “old” and new chemistry against this pest. At least one more year data is needed to make conclusive recommendations in favor or against any on these products.


Table 1. List of treatments, rate, mode of application and total area sprayed.

Treatment #


Mode of Application

Total area sprayed (acres)

1 Untreated Control - - - 2 Movento 5.00 Foliar/ground 0.0312213 3 Oberon 4 8.00 Foliar/ground 0.0312213 4 Leverage 360 2.80 Foliar/ground 0.0312213 5 Sivanto 14.00 Foliar/ground 0.0312213 6 Rimon 12.00 Foliar/ground 0.0312213 7 Assail 1.10 Foliar/ground 0.0312213 8 Assail 1.70 Foliar/ground 0.0312213

Table 2. Mean potato psyllid (±SE) counts seven days after first application of foliar insecticides, Hermiston, Oregon 2012.


Untreated Control 0.25 ± 0.25a 5.00 ± 3.08a 0.50 ± 0.29c

Movento 0.00 ± 0.00a 1.00 ± 0.58a 1.00 ± 0.41bc

Oberon 4 0.00 ± 0.00a 4.00 ± 3.34a 1.75 ± 0.75abc

Leverage 360 0.25 ± 0.25a 4.00 ± 2.27a 0.50 ± 0.29c

Sivanto 0.25 ± 0.25a 0.25 ± 0.25a 0.00 ± 0.00c

Rimon 0.00 ± 0.00a 1.25 ± 0.63a 3.50 ± 1.44a

Assail (1.10 oz) 0.50 ± 0.29a 1.00 ± 1.00a 0.50 ± 0.29c

Assail (1.70 oz) 0.00 ± 0.00a 1.50 ± 1.50a 0.75 ± 0.48c

*Adults were sampled with a DVAC and nymphs and eggs were sampled collecting leaves. Means within the same column that share the same letter are not significantly different.


Table 3. Mean potato psyllid (±SE) counts fourteen days after the first application of foliar insecticides, Hermiston, OR 2012.



Movento 0.75 ± 0.48a 1.25 ± 0.75a 4.25 ± 3.61a

Oberon 4 2.00 ± 1.15a 1.25 ± 0.95a 0.25 ± 0.25a

Leverage 360 1.00 ± 1.00a 0.50 ± 0.29a 0.25 ± 0.25a

Sivanto 0.75 ± 0.25a 0.50 ± 0.50a 0.25 ± 0.25a

Rimon 0.75 ± 0.48a 5.25 ± 3.20a 1.25 ± 0.75a

Assail (1.10 oz) 1.75 ± 0.75a 1.00 ± 0.71a 2.00 ± 1.68a

Assail (1.70 oz) 2.00 ± 0.71a 4.25 ± 2.98a 2.00 ± 1.08a

*Adults were sampled with a DVAC and nymphs and eggs were sampled collecting leaves. Means within the same column that share the same letter are not significantly different. Table 4. Mean potato psyllid (±SE) counts seven days after the second application of foliar insecticides, Hermiston, OR 2012.


Untreated Control 5.75 ± 1.31a 0.50 ± 0.29bcd 3.25 ± 2.14a

Movento 1.75 ± 0.85a 0.00 ± 0.00d 0.00 ± 0.00a

Oberon 4 3.50 ± 0.65a 0.50 ± 0.29bcd 0.25 ± 0.25a

Leverage 360 3.75 ± 2.06a 0.00 ± 0.00d 0.00 ± 0.00a

Sivanto 4.50 ± 2.87a 0.00 ± 0.00d 0.25 ± 0.25a

Rimon 5.25 ± 1.80a 0.25 ± 0.25 cd 0.25 ± 0.25a

Assail (1.10 oz) 3.75 ± 2.46a 0.25 ± 0.25cd 1.25 ± 0.95a

Assail (1.70 oz) 4.50 ± 1.85a 2.25 ± 0.85a 0.50 ± 0.29a

*Adults were sampled with a DVAC and nymphs and eggs were sampled collecting leaves. Means within the same column that share the same letter are not significantly different.


Efficacy of selected pesticides rotation programs on potato psyllid control and zebra chip disease incidence – Part III

Objectives To compare season long chemical control against the potato psyllid in Oregon. Plots information (same as in Part I and II) Insecticide Rotation Programs All programs, EXCEPT program 3, received Maxim 4FS in furrow at planting at a rate of 0.08 fl oz/100lbs seed (Table 1). All foliar applications were made at a frequency of 7-10 days as requested by chemical companies otherwise noted (Table 1). Methods Sampling started after plant emergence (4 June 2012). Un-baited yellow sticky cards and DVAC (inverted leaf blower) were used to detect the first occurrence of psyllid adults in the research plots. Sampling occurred only in the two center rows targeting the middle to the bottom of the plants. Also, 10 leaves from the center and bottom part of the plants from the central two rows were sampled. DVAC was used to sample adults, while leaves were sampled to look for psyllid eggs or nymphs. No action threshold exists for psyllids in potato, thus the action threshold was detection of potato psyllids at any life stage. As season progressed, and plants started showing typical ZC symptoms, plants were selected for PCR analysis to confirm the disease (Crosslin, JM., H Lin, JE Munyaneza. 2011. Detection of “Candidatus Liberibacter solanacearum” in the potato psyllid by conventional and real-time PCR. Southwestern Entomologist 36(2): 125-135). Zebra chip ratings was determined by collecting 100 tubers per plot two weeks after vines were beat and vine killed. The 0-3 Texas rating scale was used (top and bottom end of each tuber). Data Analyses. Analyses were performed using randomized block ANOVA of arthropod densities and Least Significant Differences (LSD) Multiple Range Test (p < 0.05). Samples of adults (DVAC samples) or nymphs and eggs (leaf samples) were analyzed separately. Each sampling date, following insecticide treatments, was also analyzed separately. Zebra chip ratings were analyzed using a one-way ANOVA with treatment as the main factor for each set of

ratings: stolon end and bud end. All analyses were performed using JMP 10. Results Phytotoxicity was noted. Psyllid populations increased as the season progressed, particularly in untreated control plots (Fig. 1). Psyllid population on 9 July (one week after first application) was low and not suitable for trends comparisons or statistical differences. On 16 July and 23 July numbers of psyllids (adults, eggs and nymphs) were still low in the experimental plots (sentinel plots at the HAREC suggested that psyllids were colonizing in the area).


Psyllid populations on 30 July Potato psyllid adults, nymphs, and eggs counts after selected chemical application are shown in Table 2. There were no significant differences for psyllid adults or nymphs though programs 2 (Movento), 3 (Movento, 4 (Movento), 5 (Rimon) and 7 (Torac 15 EC). However, there were significant differences for potato psyllid eggs counts. Program 3 (Movento) had significantly higher numbers of eggs compared to all the other treatments (2.75 ± 1.31 potato psyllid eggs per plot). Psyllid populations on 6 August Potato psyllid adults, nymphs, and eggs counts after selected chemical application are shown in Table 3. There were no significant differences for potato psyllid adults, nymphs, or eggs. However, programs 2 (Beleaf), had the lowest numbers of psyllids (eggs, nymphs and adults) compared to the control. Programs 5 (no application) presented low mean number of potato psyllid adults and eggs compared to the control; a week earlier that plot was sprayed with Rimon. Program 7 (Torac 15 EC) also showed low mean number of potato psyllid adults and eggs compared to the control. Psyllid populations on 13 August Potato psyllid adults, nymphs, and eggs counts after selected chemical application are shown in Table 4. There were no significant differences for psyllid adults or eggs. Programs 4 (Fulfill) and 7 (Torac 15 EC) had the lowest number of psyllid adults compared to the control. Programs 2 (Beleaf) and 6 (No application) had the lowest numbers of eggs compared to the control; program 6 was previously sprayed with Torac 15 EC. There were significant differences between programs for potato psyllid nymph counts. Program 6 (no application) had significantly lower numbers of nymphs compare to program 2 (Beleaf) and 3 (Fulfill). Programs 6 (no application) and 7 (Torac 15 EC) also showed low numbers of potato psyllid nymphs compared to other programs. Psyllid populations on 20 and 23 of August Potato psyllid adults, nymphs, and eggs counts after selected chemical application are shown in Table 5. There were no significant differences between treatments for psyllid adults, nymphs, or eggs. Program 4 (Rimon) had the lowest mean number of psyllid adults. Programs 6 (no application) and 7 (Torac 15 EC) had low numbers of potato psyllid nymphs. Programs 2 (Oberon) and 6 (no application) had lower numbers of psyllids eggs. Psyllid populations on 27 August Potato psyllid adults, nymphs, and eggs counts after selected chemical application are shown in Table 6. There were no significant differences between treatments for psyllid adults, nymphs, or eggs. Program 4 (Rimon) had the lowest mean number of psyllid adults. Programs 4 (Rimon) and 7 (Torac 15 EC) had the lowest numbers of potato psyllid nymphs as compared to the other treatments. Programs 2 (Oberon), 4 (Rimon), and 7 (Torac 15 EC) performed well regarding potato psyllid eggs counts, although no significant. Psyllid populations on 4 September


Potato psyllid adults, nymphs, and eggs counts after selected chemical application are shown in Table 7. There were significant differences between treatments for psyllid adults and nymphs. Programs 3 (Warrior) and 4 (Warrior) had significantly lower numbers of psyllid adults compared to the control. Programs 7 (no application) and 4 (Warrior) had significantly lower numbers of potato psyllid nymphs compared to the control. There were no significant differences for psyllid eggs, though both programs 3 (Warrior) and 4 (Warrior) had lower numbers compared to the control ant Program 7 (no application). Zebra chip ratings The results for the ZC ratings are shown in Table 8. There were significant differences for ZC rating on the solon end and on the bud end of the tuber. Based on ratings on the stolon end, Program 4 performed significantly better than that control and most of the other programs. Program 4, with the lowest ZC ratings, was followed by Programs 5 and 2. In program 7 ZC rating was significantly higher than the control, followed by Program 6. Based on ZC ratings for the bud end, Program 7 had significantly higher ZC ratings compared to the control and all the other programs. While differences were not significant, for bud end rating, programs 4, 5, and 2 presented the lowest mean. Conclusions


In experimental plots, high numbers of psyllids (adults, nymphs and eggs) were present in control plots. Less than 1% were positive for Liberibacter. Growers in the region were proactively spraying fields to control psyllids throughout the season. It was decided to terminate plots when psyllid counts in control plots were high. This decision was reached in order to reduce the risk of psyllid infestation in the area. The long season programs were kept until the end.

On 30 July, only potato psyllid egg counts showed significant differences. Program 3 (Movento) had significantly higher numbers of eggs compared to the other programs.

On 13 August, though not significant, programs 4 (Fulfill) and 7 (Torac EC) presented the lowest numbers of potato psyllid adults.

On 4 September, programs 3 (Warrior) and 4 (Warrior) had significantly lower numbers of adults compared to the control. A similar trend was seen with potato psyllid eggs. Program 4 (Warrior) presented significantly lower numbers of potato psyllid nymphs compared to the control.

The most accurate assessment of each rotational program is determined by ZC ratings.

Previous research at the HAREC showed that there are differences in ratings between the stolon and bud end of the potato tubers. Stolon ends tend to present at the beginning a higher ZC rate. As season progresses, the bacteria “moves” throughout the tuber reaching the bud end.

Based on ZC ratings of the stolon end, program 4 performed significantly better than the control, and several of the other programs. Programs 2 and 5 also presented relatively low ratings. Programs 6 and 7 performed under performed. This was expected since several frequency of application was 14 days or longer.


Program 2 consistently maintained low numbers of psyllids, mainly nymphs and eggs. ZC ratings support these finding, as program 2 achieved lower mean ratings for both the stolon and bud ends.

Program 3 maintained only moderate to poor psyllid control through a majority of the study. Better control was achieved following the application of Warrior at the end of the season. Zebra chip ratings support this trend, as mean ratings were comparable to the control for the stolon end, and higher than the control for the bud end.

Program 4 maintained psyllid populations at low, sometimes significantly low, levels, particularly for adults. This program also had the lowest mean ZC ratings for the stolon end and low ratings for the stolon end. This program consistently performed well.

Program 5 supplied variable low-moderate control of psyllid populations. At times psyllid populations were relatively high. However, ZC ratings of the bud and stolon end were relatively low compared to the control.

Program 6 also supplied variable low to moderate control of psyllid populations through the season. Most of the time, this program maintained populations lower than the control. However, the ZC ratings for the stolon end were relatively high, as were the ratings for the bud end.

Program 7 maintained lower psyllid populations early in the season, but control appeared to fail later in the season since frequency of application was 14 days or longer.

Conclusions Some of the insecticides tested proved to have a good activity against potato psyllid in the adult and/or immature stages. Preliminary data suggest promising rotations against the potato psyllid. Al least one more year data is needed to make conclusive recommendations in favor of any of these rotations. Products should be tested in well thought out rotation schemes.


Table 1. Long season control rotation programs for potato psyllids, Hermiston, Oregon 2012.

Program Date(s) of treatment


Mode of application

1

Untreated Control - -

2

Platinum 2.67 In furrow at planting

2 July Fullfill 5.5 Foliar/ground


16 July Movento 5 Foliar/ground


31 July Beleaf 2 Foliar/ground

6 August Beleaf 2 Foliar/ground

13 August Oberon 4 8 Foliar/ground

20 August Oberon 4 8 Foliar/ground

3

Cruiser Max 0.3 Seed treatment

2 July Agrimek + NIS 16 Foliar/ground





6 August Fullfill 5.5 Foliar/ground

13 August Rimon 12 Foliar/ground


27 August Warrior 1.92 Foliar/ground

4

Platinum 75 SG 2.67 In furrow at planting






6 August Fullfill 5.5 Foliar/ground




5




23 July Rimon 12 Foliar/ground



6


Admire Pro 8.7 In furrow at planting

2 July Torac 15 EC + adj 24 Foliar/ground

9 July Movento + adj 5 Foliar/ground

16 July Movento + adj 5 Foliar/ground


7

Admire Pro 8.7 In furrow at planting






6 August Torac 15 EC + adj 24 Foliar/ground




Table 2. Mean potato psyllids (±SE) counts on July 30, Hermiston, Oregon 2012.

Treatment # Treatment Adults Nymphs Eggs

1 Untreated Control 0.25 ± 0.25a 5.00 ± 3.08a 0.50 ± 0.29b

2 Movento 0.00 ± 0.00a 0.00 ± 0.00a 1.50 ± 0.65b

3 Movento 0.25 ± 0.25a 1.00 ± 0.71a 2.75 ± 1.31a

4 Movento 0.5 ± 0.29a 0.75 ± 0.75a 0.50 ± 0.29b

5 Rimon 0.5 ± 0.29a 1.00 ± 0.41a 0.50 ± 0.50b

6 No application 0.00 ± 0.00a 1.00 ± 0.58a 0.75 ± 0.48b

7 Torac 15 EC 0.00 ± 0.00a 0.00 ± 0.00a 0.25 ± 0.25b *Samples consist of either DVAC samples for adults or leaf samples for nymphs and eggs. Numbers with the same letter within a column are not significantly different. The foliar insecticide used (July 13) is listed on Table 1.

Table 3. Mean potato psyllids (±SE) counts on 6 August. Hermiston, Oregon 2012.


1 Untreated Control 4.50 ± 2.63a 5.00 ± 3.72a 2.50 ± 1.19a

2 Beleaf 0.75 ± 0.25a 0.00 ± 0.00a 0.25 ± 0.25a

3 Fulfill 1.50 ± 0.65a 1.25 ± 0.48a 1.00 ± 0.58a

4 Fulfill 2.25 ± 0.48a 0.75 ± 0.48a 0.50 ± 0.29a

5 No application 0.50 ± 0.50a 2.00 ± 1.22a 0.75 ± 0.75a

6 Torac 15 EC 1.25 ± 0.48a 1.75 ± 1.75a 0.00 ± 0.00a

7 Torac 15 EC 0.75 ± 0.75a 1.00 ± 1.00a 0.75 ± 0.75a * Samples consist of either DVAC samples for adults or leaf samples for nymphs and eggs. Numbers with the same letter within a column are not significantly different. The foliar insecticide used (July 31) is listed on Table 1.


Table 4. Mean potato psyllids (±SE) per sample for each treatment on 13 August, Hermiston, Oregon 2012.


1 Untreated Control 5.75 ± 1.31a 0.50 ± 0.29bcd 3.25 ± 2.14a

2 Beleaf 3.50 ± 0.65a 1.25 ± 0.63abc 0.50 ± 0.50a

3 Fulfill 4.00 ± 0.41a 1.50 ± 0.65 abc 1.00 ± 1.00a

4 Fulfill 0.75 ± 0.48a 0.75 ± 0.48 bcd 0.00 ± 0.00a

5 Rimon 4.00 ± 1.47a 0.25 ± 0.25cd 1.00 ± 1.00a

6 No application 2.25 ± 0.48a 0.00 ± 0.00d 0.00 ± 0.00a

7 Torac 15 EC 1.50 ± 0.65a 0.25 ± 0.25cd 0.50 ± 0.50a * Samples consist of either DVAC samples for adults or leaf samples for nymphs and eggs. Numbers with the same letter within a column are not significantly different. The foliar insecticide used (6 August) is listed on Table 1.

Table 5. Mean potato psyllids (±SE) on 20 and 23 August, Hermiston, Oregon 2012.



2 Oberon 4 5.25 ± 2.29a 2.50 ± 0.96a 6.50 ± 3.12a

3 Rimon 4.50 ± 1.94a 1.50 ± 1.19a 1.75 ± 1.11a

4 Rimon 2.25 ± 1.11a 0.75 ± 0.75a 2.50 ± 2.18a

5 Warrior 6.00 ± 1.47a 5.75 ± 5.42a 9.25 ± 4.03a

6 No application 3.25 ± 1.38a 0.50 ± 0.50a 2.00 ± 1.00a

7 Torac 15 EC 1.75 ± 0.63a 0.25 ± 0.25a 4.25 ± 2.25a * Samples consist of either DVAC samples for adults or leaf samples for nymphs and eggs. Numbers with the same letter within a column are not significantly different. The foliar insecticide used is listed on Table 1.


Table 6. Mean potato psyllids (±SE) on 27 August, Hermiston, Oregon 2012.

* Samples consist of either DVAC samples for adults or leaf samples for nymphs and eggs. Numbers with the same letter within a column are not significantly different. The foliar insecticide used (20 August) is listed on Table 1.

Table 7. Mean psyllids (±SE) per sample for each treatment on 4 September, Hermiston, Oregon 2012.



2 No application - - -

3 Warrior 3.00 ± 1.08b 8.00 ± 2.48ab 5.25 ± 2.25a

4 Warrior 3.25 ± 1.31b 2.00 ± 0.41b 5.25 ± 2.36a



7 No application 6.75 ± 1.11a 1.25 ± 0.95b 15.25 ± 7.92a * Samples consist of either DVAC samples for adults or leaf samples for nymphs and eggs. Numbers with the same letter within a column are not significantly different. The foliar insecticide used (27 August) is listed on Table 1.


1 Untreated control 12.25 ± 2.39a 5.00 ± 2.27a 7.00 ± 4.85a

2 Oberon 4 14.25 ± 3.12a 4.25 ± 1.65a 5.75 ± 3.54a

3 Rimon 15.67 ± 4.18a 6.00 ± 5.51a 12.00 ± 3.61a

4 Rimon 11.00 ± 4.51a 3.50 ± 0.65a 5.25 ± 4.27a



7 Torac 15 EC 14.75 ± 4.09a 1.00 ± 0.71a 4.50 ± 0.29a


Table 8. Mean zebra chip ratings (±SE), Hermiston, Oregon 2012. Ratings include one measurement for the stolon and bud end of 100 potato tubers per treatment (Texas 0-3 scale).

Treatment Stolon end Bud end

Untreated Control 0.244 ± 0.012bc 0.007 ± 0.002b

2 0.203 ± 0.012cd 0.005 ± 0.004b

3 0.225 ± 0.015bc 0.023 ± 0.009b

4 0.163 ± 0.013d 0.008 ± 0.005b

5 0.206 ± 0.010c 0.006 ± 0.002b

6 0.261 ± 0.013b 0.014 ± 0.004b

7 0.330 ± 0.025a 0.121 ± 0.020a * Numbers with the same letter within a column are not significantly different.


Figure 1. Mean potato psyllid counts (±SE) in the control over the season, Hermiston, Oregon 2012.*

* Eggs and nymphs were collected in a sample of 10 leaves/plot. Adults were sampled using a DVAC.


Pictures (Photo credits OSU-HAREC-IAEP Rondon’s Lab) The potato psyllid (top left, eggs; top right, nymph; bottom left, mature adult; bottom right, “young” adult)

(Photo credits OSU-HAREC-IAEP Rondon’s Lab, Murphy)

Texas scale (0-3)

(Photo credits OSU-HAREC-IAEP (Rondon’s lab)


Sequence of ZC damage; week 1, purple leaves; week 2, few plants start going down; week 3, potato plants dead.

(Photo credits OSU-HAREC-IAEP Rondon’s Lab)

Zebra chip disease



Using the DVAC (inverted leaf blower) to collect psyllids


Sticky cards in the efficacy trials



Crew sorting samples in the IAEP lab


IAEP (Rondon’s lab) 2012 crew (psyllid scouts!)


Pictures (Photo credits OSU-HAREC-IAEP Rondon’s Lab)

insect management and pesticide...

Documents