Willow leaf beetle

The willow leaf beetle (Latin Lochmaea capreae) is a member of the order Coleoptera and the family Chrysomelidae. This insect is a significant specialist pest that primarily targets various species of willow (Salix) and birch (Betula), although it can also be found on poplars and alders in forest and landscape environments.

Both adult beetles and larvae contribute to the damage, though their feeding habits differ slightly. Adults cause damage in early spring by skeletonizing or perforating developing leaves. Larvae appear later and feed gregariously on the leaf underside, consuming tissue until only a network of veins remains, often leading to partial or complete defoliation of the host plant.

The life cycle of Lochmaea capreae consists of one generation per year. The species overwinters as an adult in the leaf litter, debris, or upper soil layers beneath the canopy of host trees. Once temperatures rise in the spring, the beetles emerge, feed on young foliage, and mate. Females subsequently deposit clusters of eggs on the undersides of leaves.

The larval stage consists of three instars, during which they grow rapidly while feeding on leaves. Once they reach maturity, they descend to the ground to pupate in the soil. The pupal stage typically lasts about two weeks, after which the new generation of adult beetles emerges in mid-to-late summer to feed briefly before seeking shelter for winter hibernation.

Effective management strategies include the following:

• Application of selective contact or systemic insecticides during the peak larval feeding stage.
• Sanitation practices, such as removing leaf litter where adults overwinter.
• Biological control through the use of natural predators or entomopathogenic fungi.
• Monitoring of tree stands in early spring to identify initial infestation levels.