Hornet moth

The hornet moth (latin: Aegeria apiformis) is a significant wood-boring pest belonging to the Sesiidae family of the order Lepidoptera. Its common name stems from its remarkable mimicry of the hornet (Vespa crabro), which serves as a defensive strategy against predators. With transparent wings and a stout, yellow-and-black striped body, it is easily mistaken for a stinging hymenopteran.

This moth primarily targets species within the Populus genus, such as poplar and aspen, and occasionally willow. The larvae are strictly internal feeders, burrowing into the lower trunks and root collars of host trees. Young trees in plantations and nurseries are particularly vulnerable to heavy infestation, which can lead to structural weakness.

The biological cycle of the hornet moth is prolonged, typically requiring two to three years to complete in temperate climates. The larvae overwinter within the galleries they have excavated inside the wood. Adult moths emerge in the summer, typically between June and August, to mate and lay eggs at the base of the host trees.

The damage caused is primarily internal and insidious. Larvae excavate tunnels in the bark and sapwood, which disrupts the tree's vascular system. This infestation causes the foliage to thin, branches to die back, and in severe cases, it causes total tree failure. Furthermore, the larval galleries provide entry points for secondary pathogens and wood-decay fungi.

Control measures emphasize integrated pest management. Silvicultural practices are paramount, including the systematic removal and destruction of heavily infested trees to reduce population pressure. Monitoring for adult activity using pheromone traps is highly recommended. In nursery settings, applications of targeted systemic insecticides during the peak egg-hatching period can be effective in preventing larval establishment.