Elm flea weevil

Systematic position. The elm flea weevil (Rhynchaenus excellens) belongs to the order Coleoptera, family Curculionidae, and subfamily Orchestinae. It is a specialized pest known for its high jumping ability, which is characteristic of the genus and explains the common name.

Host plants and damage type. This pest primarily attacks various elm species (Ulmus spp.). The adult weevils feed by chewing small holes in the leaf surface, causing a shot-hole effect. However, the most significant damage is caused by the larvae, which are leaf miners, creating serpentine or blotch mines inside the leaf tissue that impair the tree's photosynthetic capacity.

Biology and life cycle. The life cycle involves overwintering as adults in protected spots such as bark crevices, leaf litter, or topsoil. As spring arrives, they emerge to feed on developing buds and leaves. After mating, females insert eggs into the leaf tissue. Larval development occurs entirely within the leaf, after which they pupate inside the mine, completing their transformation into adults.

Economic impact. While often considered a minor pest, high populations can cause severe defoliation, which stresses the host trees, especially in urban environments. Persistent attacks over several years can lead to the decline of branch health, stunted growth, and increased susceptibility to secondary pests or pathogenic fungi, significantly affecting the aesthetic value of urban plantings.

Control measures. Integrated pest management (IPM) is essential for controlling this weevil. Cultural practices include the removal and destruction of fallen leaves in autumn to reduce the overwintering population. Chemical control involves the application of systemic or contact insecticides during the early adult emergence period. Monitoring for the first signs of leaf mining activity is critical to timing insecticide applications effectively before widespread damage occurs.