Managing the Pea Leaf Weevil in Field Peas

Abstract

Summary The pea leaf weevil is one of the few insect pests of field peas in southern Alberta and southwest Saskatchewan. Adults cause distinctive notching on seedlings which generally does not affect yield. Larval feeding on nitrogen-fixing root nodules may reduce yield if soil is nitrogen deficient. Only field peas and faba beans are at risk of damage. Other crops in the bean family may be fed on by adults but do not suffer significant damage from larvae. The economic threshold during the second to fifth node stages in field peas is 30% of seedlings with damage to the terminal (clam) leaf. Seed treated with thiamethoxam has produced more consistent yield responses than application of foliar insecticides but additional farm-level trials are required. Trap cropping the pea leaf weevil can be done by planting a border in the fall with winter peas or adjacent, earlier planting of a spring cultivar. Close monitoring of the trap crop is needed to control the weevils in the trap crop area before they move to the rest of the field. Fields under no tillage regimes suffer less damage than those under conventional tillage. Biological control is a research area that should be pursued for sustainable management of this pest.