Poplar hawk-moth

The Poplar hawk-moth (Laothoe populi) is a large moth belonging to the Sphingidae family within the order Lepidoptera. While widely appreciated by entomologists for their unique appearance, the larval stage (caterpillars) can occasionally reach population densities that threaten the health of specific tree species.

The primary hosts for this species include trees such as poplars (Populus spp.), willows (Salix spp.), and aspens. In nursery settings or orchards adjacent to woodland, these caterpillars may occasionally feed on fruit-bearing trees, consuming the foliage and impacting the plant's overall vigor.

The biological cycle consists of the egg, five larval instars, pupa, and adult moth. The insect typically overwinters as a pupa buried in the soil. Adults emerge in late spring or early summer. Females lay eggs singly on the undersides of host leaves, and the resulting larvae feed until they are ready to pupate in the soil.

The primary damage is caused by the caterpillars' voracious appetite for leaves. They are capable of stripping large portions of the canopy, leading to significant defoliation. In cases of high infestation, the loss of leaf surface area inhibits photosynthesis, which can stunt tree growth and stress young or weak saplings.

Effective management strategies against this pest include:

• Manual removal of caterpillars from smaller, ornamental trees.
• Cultivating the soil beneath host trees in autumn to expose or kill overwintering pupae.
• Application of Bacillus thuringiensis sprays targeting young larvae to minimize environmental impact.
• Use of systemic or contact insecticides during peak feeding periods if thresholds are exceeded.