Waved sphinx moth

The Waved sphinx moth (Ceratomia undulosa) is a member of the order Lepidoptera and the family Sphingidae. It is a well-known North American insect species whose larvae specialize in feeding on the foliage of broad-leaved deciduous trees. The adult moth is characterized by its large size and complex patterns on its wings, which provide excellent camouflage against tree bark.

The primary host plants for the larvae of this species are trees in the genus Fraxinus (ash), though they are also frequently found on related plants like privet (Ligustrum) and lilac (Syringa). While usually present in low numbers, outbreaks can lead to significant defoliation of both individual ornamental trees and large forest stands.

The biological cycle follows a complete metamorphosis: egg, larva, pupa, and adult. Females typically deposit eggs singly on the undersides of leaves. Upon hatching, the larvae undergo five developmental stages (instars). Once the larval growth phase is complete, they descend to the soil and pupate underground, entering a state of diapause where they spend the winter.

The damage caused by the Waved sphinx is primarily defoliation. Early-stage larvae skeletonize the leaves, while later instars consume entire leaves, leaving only the midribs. This intensive feeding reduces the tree's photosynthetic capacity, which, if sustained over multiple years, can lead to stunted growth, branch dieback, and increased vulnerability to diseases or wood-boring insects.

Integrated Pest Management (IPM) is recommended for controlling this moth. Biological control, specifically applying Bacillus thuringiensis (Bt), is highly effective when targeting younger larvae. In residential or municipal settings where trees are at high risk, systemic insecticides can be applied during the early season. Additionally, maintaining soil health and removing debris around the base of the trees helps disrupt the pupation cycle of the pest.