Great ash sphinx

Systematic position
The Great ash sphinx (Sphinx chersis) is a moth belonging to the order Lepidoptera and the family Sphingidae. It is a well-known species in North America, recognizable by its large size and specialized host plant requirements, often affecting various ornamental and forest trees.

Host plants
The larvae of this species primarily feed on plants within the Oleaceae family. Their preferred hosts include various species of ash (Fraxinus), lilac (Syringa), and privet (Ligustrum). Because these plants are staples in residential landscaping, the moth is frequently encountered in urban and suburban environments.

Biology and life cycle
This moth undergoes complete metamorphosis. Adults are nocturnal, active pollinators, while the larval stage is strictly herbivorous. Females deposit eggs on the leaves of host plants. After hatching, larvae feed voraciously, molting through several instars before descending to the soil to pupate in underground chambers, where they usually overwinter.

Damage and economic impact
Damage is inflicted by the larval stage, which has a significant appetite.

• Defoliation of host trees and shrubs.
• Significant reduction in photosynthetic capacity.
• Stunted growth in young saplings due to loss of foliage.
• Reduction of the ornamental value of garden shrubs.

Control measures
Effective management involves monitoring and timely intervention. For small trees, manual removal of caterpillars is often sufficient and ecologically safe. For larger infestations, applying biological insecticides (like those containing Bacillus thuringiensis) or broad-spectrum insecticides may be necessary. Soil cultivation around the base of the host plants in late autumn can help destroy pupating larvae.