Pest description and crop damage A small, dark weevil, 0.12 inch long, that resembles the pea weevil but is only half as large. These weevils are almost always in western Oregon vetch seed crops and require control. They move into hairy vetch varieties at first bloom and lay eggs on new pods. Larvae hatch in 7 to 10 days, burrow through the seed pod, and destroy developing seeds. All hairy vetch varieties are susceptible to damage. Note: This weevil does not infest the seeds of plain or smooth vetch varieties.
Apply insecticides shortly after the first pods appear and when eggs are seen on them in order to kill adults before they begin to lay eggs in large numbers. Once eggs are on pods, it is too late to prevent weevil infestation of seeds.
- malathion at 1 to 1.25 lb ai/a. PHI 0 days. REI 12 hr. Malathion does not kill eggs and lacks sufficient residual activity to kill larvae hatching from these eggs and entering pods. Avoid applying spray on bloom. Malathion is toxic to all bees. If necessary to control pests in blooming crop, apply only in evening or early morning, when bees are not actively foraging in the vetch. Always contact beekeeper before applying.
- zeta-cypermethrin (Mustang MAX) at 0.014 to 0.025 lb ai/a. PHI 3 days for cutting or grazing; 7 days hay, seed. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.025 lb ai/a per cutting nor 0.75 lb ai/a per season.