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Performance of Commercial Insecticides Against Potato Leafhopper
Crop and Soil Environmental News, July 1999
R. R. Youngman, C. A. Laub, T. P. Kuhar, and T. A. Dellinger
Department of Entomology
The following tables show results of several commercial insecticides that we have evaluated against potato leafhopper on alfalfa in Virginia. In most cases, insecticides significantly reduced potato leafhopper numbers below that of the untreated check. Those insecticides that consistently gave superior control of potato leafhopper nymphs and adults for approximately 14 to 21 days after treatment (DAT) include: Baythroid 2E, Warrior T 1CS (= Karate 2.09CS), Lorsban 4E, Pounce 3.2EC, and Furadan 4F.
The last table lists performance ratings of commercial insecticides reported in potato leafhopper efficacy trials from other alfalfa producing states, as well as Virginia, for the period from 1993-1997. This information is published annually by the Entomological Society of America in Arthropod Management Tests. We rated insecticides as either excellent (E), good (G), fair (F), or poor (P) depending on how well they controlled potato leafhopper nymphs and adults compared to their respective controls for up to three weeks.
1998 Insecticide Efficacy Trial; Montgomery Co., Virginia
| Treatment | Rate (lb AI/ac) | Potato leafhoppers/10 sweeps | ||||
| Pre-spray (13 Jul) | 4 DAT (17 Jul) | 10 DAT (23 Jul) | 15 DAT (28 Jul) | 23 DAT (5 Aug) | ||
| Baythroid 2E | 0.0125 | 13.0 | 0.6b* | 1.0b | 0.6c | 1.6c |
| Furadan 4F | 0.5 | 12.0 | 0.0b | 0.0b | 0.6c | 1.0c |
| Lannate 2.4LV | 0.9 | 13.6 | 0.0b | 1.0b | 5.6b | 8.0b |
| Lorsban 4E | 0.5 | 13.6 | 0.0b | 0.6b | 1.6c | 3.0bc |
| Warrior T 1CS | 0.015 | 15.0 | 1.0b | 0.6b | 0.0c | 1.6c |
| Check (untreated) | -- | 10.0 | 2.6a | 29.0a | 33.0a | 47.6a |
1997 Insecticide Efficacy Trial; Montgomery Co., Virginia
| Treatment | Rate (lb AI/ac) | Potato leafhoppers/10 sweeps | |||||
| Pre-spray (18 July) | 5 DAT (23 July) | 10 DAT (28 July) | 15 DAT (2 Aug.) | 20 DAT (7 Aug.) | 24 DAT (11 Aug.) | ||
| Baythroid 2E | 0.025 | 9.0 | 0.0c | 1.6c | 2.0de | 4.0c | 2.6de |
| Dimethoate 4EC | 0.50 | 15.6 | 1.6b | 6.0b | 13.0c | 6.0bc | 7.4c |
| Furadan 4F | 0.50 | 11.0 | 1.6b | 3.0bc | 21.6b | 13.0b | 14.6b |
| Karate 2.09CS | 0.025 | 12.6 | 0.0c | 1.6c | 1.0e | 4.0bc | 1.0e |
| Pounce 3.2EC | 0.10 | 14.0 | 0.0c | 1.6c | 12.6c | 8.6bc | 6.6cd |
| Pounce 3.2EC | 0.15 | 13.6 | 0.0c | 1.6c | 9.0c | 7.4bc | 6.0cd |
| Pounce 3.2EC | 0.20 | 12.0 | 0.0c | 0.6c | 3.0de | 2.6c | 6.0cd |
| Check (untreat.) | -- | 8.6 | 13.6a | 35.6a | 87.0a | 77.0a | 98.0a |
1996 Insecticide Efficacy Trial; Montgomery Co., Virginia
| Treatment | Rate (lb AI/ac) | Potato leafhoppers/10 sweeps | ||||
| Pre-treatment (29 July) | 4 DAT (02 Aug) | 8 DAT (06 Aug) | 12 DAT (10 Aug) | |||
| Baythroid 2E | 0.028 | 7.0 | 0.6b | 0.6b | 0.6b | |
| Dimethoate 4EC | 0.5 | 5.6 | 0.0b | 0.0b | 1.6b | |
| Furadan 4F | 0.5 | 8.6 | 0.6b | 0.0b | 2.0b | |
| Karate 1E | 0.025 | 6.0 | 0.6b | 0.6b | 0.0b | |
| Penncap-M 2FM | 0.5 | 6.0 | 1.6b | 0.0b | 3.0b | |
| Check (untreated) | -- | 5.6 | 7.6a | 6.6a | 10.0a | |
1994 Insecticide Efficacy Trial; Montgomery Co., Virginia
| Treatment | Rate (lb AI/ac) | Potato leafhoppers/10 sweeps | ||||
| 4 DAT (05 July) | 7 DAT (08 July) | 11 DAT (12 July) | 15 DAT (16 July) | 21 DAT (22 July) | ||
| Ambush 2E | 0.2 | 0.3b | 1.3b | 2.0b | 3.3b | 2.3b |
| Dimethoate 4EC | 0.5 | 0.0b | 1.0b | 1.5b | 4.5b | 1.5b |
| Imidan 2.5EC | 1.0 | 0.5b | 1.5b | 2.5b | 4.3b | 3.0b |
| Check (untreated) | -- | 21.8a | 19.0a | 23.3a | 29.3a | 31.3a |
Performance of Commercial Insecticides for Control of Potato Leafhopper.
Data from ESA Arthropod Management Tests: 1993-97.
| Insecticide | No. of tests | Insecticide performance ratinga (approx. 14-21 DAT) |
| Ambush 2E | 7 | E,E,E,E,E,E,G |
| Baythroid 2E | 21 | E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,E |
| Dimethoate 4EC | 22 | E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,G,G,G,G,G,F |
| Furadan 4F | 10 | E,E,E,E,E,G,G,G,F,P |
| Imidan 2.5EC | 5 | E,E,G,G,G |
| Lorsban 4E | 14 | E,E,E,E,E,E,E,E,E,E,G,G,F,F |
| Penncap-M 2F | 6 | E,E,E,E,E,F |
| Pounce 3.2EC | 27 | E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,G,G,G,F |
| Sevin XLR Plus | 5 | E,E,E,E,F |
| Warrior/Karate | 22 | E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,E,G,F |