Clover Weevils

several species of beetles of the genus Apion of the family Curculionidae that are clover pests. They are distributed wherever clover is cultivated. They primarily damage the generative organs (the seed-eating Apion) and stems (the stem Apion). The most common species of seed-eating clover weevils are Apion apricans, which is the most dangerous, A. aestivum, and A. flavipes. The weevils winter in the surface layer of the soil and under plant remains on clover fields, the edges of forests, and shrub thickets. In the spring they settle in clover plantings, chewing small openings and pits in the leaves. They deposit their eggs in leaf buds, flower buds, or blossoms. The larvae, which eat the generative organs, pupate in the thalamus. The beetles hatch in the middle of the summer. In some years, seed-eating clover weevils decrease a harvest by 30–50 percent.

The stem Apion include pests of alsike clover, the species A. seniculus, and pests of red clover, the species A. virens. These insects winter in the same place as the seed eaters and in the spring feed on clover leaves. They lay their eggs in the stems. The larvae chew out longitudinal passages in the leaves and pupate there. Damaged plants are stunted and seed harvest is reduced. Countermeasures include treating clover seeds with insecticides, mowing forage clover during budding, and rapid drying and harvesting of hay. In regions where two-harvest clover is cultivated, control measures include the use of the second harvest for seed.