Ailanthus Webworm Moth

Natural Habitat

Commonly found in urban and suburban areas where its host plant, the Ailanthus tree (tree of heaven), is present. Also found in natural areas where Ailanthus grows.

Diet & Feeding

The larvae (caterpillars) feed exclusively on the leaves of the Ailanthus tree (Ailanthus altissima). Adult moths feed on nectar from various flowers.

Behavior Patterns

The caterpillars are gregarious and spin silken webs around the leaves and branches of their host tree, feeding within these protective webs. They can defoliate portions of the tree. Adults are diurnal (active during the day) and are often seen flying around their host trees or visiting flowers. Multiple generations can occur within a year.

Risks & Benefits

Potential risk: Can cause significant defoliation to Ailanthus trees, which are often considered invasive species. However, as Ailanthus is an invasive exotic tree in many regions, the moth's feeding can be seen as a form of biological control, helping to reduce the spread and impact of this problematic tree. It poses no known direct risk to humans or domestic animals.

Identified on: 9/14/2025