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Riley Suzanne Harding, Brian A Nault, Abby Seaman, Potato Leafhopper Control in Snap Bean With Insecticides Allowed for Organic Production, 2017, Arthropod Management Tests, Volume 45, Issue 1, 2020, tsaa070, https://doi.org/10.1093/amt/tsaa070
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Potato leafhopper (Empoasca fabae Harris) is a serious pest of organically grown snap bean in New York, but little is known about efficacy of insecticides that could manage infestations. The objective of this trial was to identify effective insecticides listed by the Organic Materials Review Institute for managing potato leafhopper in snap bean. Field trials were conducted at Cornell AgriTech’s Fruit and Vegetable Research farm in Geneva, NY (GPS: 42°52′35.3″N 77°01′27.4″W). Snap bean seeds, ‘BA1001,’ were planted on 9 Jun 2017. All seed was treated with captan, metalaxyl, streptomycin, and thiram to protect against soil-borne diseases. Plots consisted of two 15-ft-long rows at 30-inch row spacing. Each two-row plot was flanked by two planted buffer rows and 3-ft of bare ground within rows to separate plots. The treatments listed in Table 1 were arranged in an RCB design and replicated six times. Spray programs were initiated when the potato leafhopper infestation reached a threshold of one nymph per trifoliate leaf. Insecticides were applied using a CO2-pressurized backpack sprayer and a two-row boom equipped with four, flat-fan nozzles (TJ-60 8002VS) that delivered 20 gallons per acre at 40 psi.
| Treatment . | Active ingredient(s) . | Rate/A . |
|---|---|---|
| Untreated check | - | - |
| Azera | Azadirachtin + pyrethrin | 40 fl oz/A |
| Pyganic specialty | Pyrethrins | 0.4% v:v |
| Thyme guard | Thyme oil | 0.5% v:v |
| Treatment . | Active ingredient(s) . | Rate/A . |
|---|---|---|
| Untreated check | - | - |
| Azera | Azadirachtin + pyrethrin | 40 fl oz/A |
| Pyganic specialty | Pyrethrins | 0.4% v:v |
| Thyme guard | Thyme oil | 0.5% v:v |
| Treatment . | Active ingredient(s) . | Rate/A . |
|---|---|---|
| Untreated check | - | - |
| Azera | Azadirachtin + pyrethrin | 40 fl oz/A |
| Pyganic specialty | Pyrethrins | 0.4% v:v |
| Thyme guard | Thyme oil | 0.5% v:v |
| Treatment . | Active ingredient(s) . | Rate/A . |
|---|---|---|
| Untreated check | - | - |
| Azera | Azadirachtin + pyrethrin | 40 fl oz/A |
| Pyganic specialty | Pyrethrins | 0.4% v:v |
| Thyme guard | Thyme oil | 0.5% v:v |
The first application was made on 11 Jul and then followed by two additional applications made at 5-d intervals. After each application (3–5 DAT), efficacy of treatments was evaluated by recording the number of nymphs per 20 randomly selected trifoliates per plot. Data were analyzed using a generalized linear mixed model in SAS (ver. 9.4; PROC GLIMMIX) where treatment was a fixed effect, and replication a random effect in the model. Treatment means were compared using Tukey’s Studentized Range (HSD) Test at P < 0.05.
Potato leafhopper densities in the Azera and Pyganic treatments were significantly lower than those in the untreated check on most sampling dates and overall (Table 2). Thyme Guard was not effective in reducing leafhopper densities. Further research should be done to understand optimal application frequency of the most efficacious treatments.1
| Product . | Number of applications . | Mean number of nymphs per trifoliate . | ||||
|---|---|---|---|---|---|---|
| . | . | 14 Jul . | 18 Jul . | 21 Jul . | 26 Jul . | Total . |
| Untreated check | - | 0.2 ± 0.1ab | 0.6 ± 0.1a | 0.5 ± 0.1ab | 0.9 ± 0.1a | 2.1 ± 0.3a |
| Azera | 3 | 0 ± 0b | 0.1 ± 0.0b | 0.2 ± 0.1b | 0.3 ± 0.1bc | 0.6 ± 0.1b |
| Pyganic specialty | 3 | 0 ± 0b | 0.2 ± 0.0ab | 0.3 ± 0.1b | 0.2 ± 0.0c | 0.7 ± 0.1b |
| Thyme guard | 3 | 0.2 ± 0.1a | 0.5 ± 0.1ab | 0.7 ± 0.2a | 0.7 ± 0.2ab | 2.1 ± 0.4a |
| P value | 0.0058 | 0.0143 | 0.0104 | 0.0016 | 0.0006 | |
| Product . | Number of applications . | Mean number of nymphs per trifoliate . | ||||
|---|---|---|---|---|---|---|
| . | . | 14 Jul . | 18 Jul . | 21 Jul . | 26 Jul . | Total . |
| Untreated check | - | 0.2 ± 0.1ab | 0.6 ± 0.1a | 0.5 ± 0.1ab | 0.9 ± 0.1a | 2.1 ± 0.3a |
| Azera | 3 | 0 ± 0b | 0.1 ± 0.0b | 0.2 ± 0.1b | 0.3 ± 0.1bc | 0.6 ± 0.1b |
| Pyganic specialty | 3 | 0 ± 0b | 0.2 ± 0.0ab | 0.3 ± 0.1b | 0.2 ± 0.0c | 0.7 ± 0.1b |
| Thyme guard | 3 | 0.2 ± 0.1a | 0.5 ± 0.1ab | 0.7 ± 0.2a | 0.7 ± 0.2ab | 2.1 ± 0.4a |
| P value | 0.0058 | 0.0143 | 0.0104 | 0.0016 | 0.0006 | |
Means (±standard error) within a column followed by the same letter are not significantly different (P > 0.05; Tukey’s Studentized Range [HSD] Test; n = 6).
| Product . | Number of applications . | Mean number of nymphs per trifoliate . | ||||
|---|---|---|---|---|---|---|
| . | . | 14 Jul . | 18 Jul . | 21 Jul . | 26 Jul . | Total . |
| Untreated check | - | 0.2 ± 0.1ab | 0.6 ± 0.1a | 0.5 ± 0.1ab | 0.9 ± 0.1a | 2.1 ± 0.3a |
| Azera | 3 | 0 ± 0b | 0.1 ± 0.0b | 0.2 ± 0.1b | 0.3 ± 0.1bc | 0.6 ± 0.1b |
| Pyganic specialty | 3 | 0 ± 0b | 0.2 ± 0.0ab | 0.3 ± 0.1b | 0.2 ± 0.0c | 0.7 ± 0.1b |
| Thyme guard | 3 | 0.2 ± 0.1a | 0.5 ± 0.1ab | 0.7 ± 0.2a | 0.7 ± 0.2ab | 2.1 ± 0.4a |
| P value | 0.0058 | 0.0143 | 0.0104 | 0.0016 | 0.0006 | |
| Product . | Number of applications . | Mean number of nymphs per trifoliate . | ||||
|---|---|---|---|---|---|---|
| . | . | 14 Jul . | 18 Jul . | 21 Jul . | 26 Jul . | Total . |
| Untreated check | - | 0.2 ± 0.1ab | 0.6 ± 0.1a | 0.5 ± 0.1ab | 0.9 ± 0.1a | 2.1 ± 0.3a |
| Azera | 3 | 0 ± 0b | 0.1 ± 0.0b | 0.2 ± 0.1b | 0.3 ± 0.1bc | 0.6 ± 0.1b |
| Pyganic specialty | 3 | 0 ± 0b | 0.2 ± 0.0ab | 0.3 ± 0.1b | 0.2 ± 0.0c | 0.7 ± 0.1b |
| Thyme guard | 3 | 0.2 ± 0.1a | 0.5 ± 0.1ab | 0.7 ± 0.2a | 0.7 ± 0.2ab | 2.1 ± 0.4a |
| P value | 0.0058 | 0.0143 | 0.0104 | 0.0016 | 0.0006 | |
Means (±standard error) within a column followed by the same letter are not significantly different (P > 0.05; Tukey’s Studentized Range [HSD] Test; n = 6).
Footnotes
This research was supported by industry gifts of pesticides and by the USDA National Institute of Food and Agriculture, Hatch project 1011209. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the National Institute of Food and Agriculture (NIFA) or the United States Department of Agriculture (USDA).
