Willow leaf beetle

The willow leaf beetle (lat. Plagiodera versicolora) is a member of the Coleoptera order and the Chrysomelidae family. This small beetle is easily recognized by its metallic, shiny appearance, which ranges from a deep blue to a bronze-green color, allowing it to blend in perfectly with its host plants.

This pest primarily targets various species of willow (Salix) and poplar (Populus). It is frequently found in nurseries, urban parks, and along riverbanks where these host trees are abundant. Young saplings are particularly susceptible to heavy infestation during the early summer months.

The life cycle of the beetle consists of four stages: egg, larva, pupa, and adult. Overwintering occurs in sheltered areas such as bark crevices, leaf litter, or the upper soil surface. As temperatures rise in spring, the adults emerge to feed and deposit clusters of yellow eggs on the undersides of leaves.

The damage is caused by both the larvae and the adults. The larvae skeletonize the leaves, consuming the leaf tissue between the veins, while the adults typically leave distinct holes in the foliage. Severe infestations can result in complete defoliation, stunted growth, and an increased susceptibility to secondary infections in the host tree.

Effective pest management strategies include both cultural and chemical control measures. It is advisable to clear away leaf litter in the autumn to reduce overwintering sites. If chemical intervention is necessary, applying systemic or contact insecticides during the larval feeding stage is the most effective way to prevent significant foliage loss.