The use of insecticide sprays for alfalfa weevil or potato leafhopper will generally reduce the effectiveness of beneficial insect populations and may require 1 to 2 years before these populations recover. Ratios of 1 or more adult or larval ladybird beetles to 10 to 50 aphids give good control. Avoid spraying your first crop because sprays will kill alfalfa weevil parasites.
Treatment is rarely needed (1 year in 15) because several new species of ladybird beetles, wasp parasites, and other beneficial insects usually control this pest. However, heavily infested plants may turn yellow and wilt during the spring. Keep fields under close surveillance early in the season during periods of cool weather. Use the same stem-bucket technique recommended for alfalfa weevil, and record the number of aphids per stem. Also, keep a relative tally of the ratio of predators to aphid numbers. If more than 50 aphids per stem of alfalfa under 10 inches or if more than 100 aphids per stem of alfalfa over 10 inches are present, early harvesting is recommended.
You are viewing records 1 - 6 of 6. Next 1 Records| Insecticide and formulation | Rate of active ingredient per acre | Rate of formulation per acre | Time lmits: Days before harvest | Remarks |
|---|---|---|---|---|
| dimethoate (Dimethoate 4EC) |
0.5 lb | 1.0 pt | 10 | Restricted Use: Effective only on cutting on which applied. May be less effective during drought conditions. |
| lambdacyhalothrin (Lambda-Cy 1EC) |
0.02-0.03 lb | 2.56-3.84 oz | 1 for forage, 7 for hay | Restricted Use: |
| lambdacyhalothrin (Warrior II) |
0.02-0.03 lb | 1.28-1.92 oz | 1 for forage, 7 for hay | Restricted Use: |
| malathion (Malathion 57EC) |
1.25 lb | 1.0 qt | 0 | Restricted Use: |
| methomyl (Lannate 2.4LV) |
0.45-0.9 lb | 1.5-3.0 pt | 7 | Restricted Use: Do not apply to dormant or semidormant alfalfa when minimum daily temperature is 50 degrees F or lower. |
