**Yellowtail Moths** (*Euproctis similis*) and their caterpillars are pests of deciduous trees across Europe and Asia. The conflict is **defoliation and skin irritation**: the caterpillar feeds on the leaves of a wide variety of deciduous trees and shrubs (especially willow, hawthorn, and fruit trees), causing defoliation. The caterpillar is also famous for its dense, irritant hairs, which can cause severe **dermatitis, rashes, and asthma** in sensitive individuals upon contact.
Taxonomy and Classification
Yellowtail Moths belong to the Order Lepidoptera (Moths and Butterflies) and the Family Erebidae (Tussock Moths). They undergo complete metamorphosis. The adults are non-feeding.
Physical Description
Larvae are 25 mm to 35 mm long.
- **Adult (Key ID):** Pure white moth with a conspicuous tuft of **bright yellow-orange hair** at the tip of the abdomen (the “yellowtail”); the female uses these hairs to cover her egg mass.
- **Larva (Key ID):** Dark brown/black caterpillar with tufts of long hairs and distinctive **white and reddish-brown stripe markings**; often found skeletonizing leaves.
- **Conflict:** Ornamental, Public Health (Urticating Hairs).
Distribution and Habitat
Found across Europe, North Africa, and temperate Asia. Habitat is hedgerows, parks, gardens, and orchards where their host trees are common.
Behavior and Conflict
The conflict is their urticating (stinging) hairs and overwintering habits.
- **Irritating Hairs:** The larval hairs are **urticating**; they break off easily and become airborne, causing skin, eye, and respiratory irritation. These hairs can remain active long after the caterpillar is dead.
- **Overwintering:** They overwinter in communal, tough silken nests attached to the twigs of host trees.
Management and Prevention
Management is **Mechanical Removal and Biological Control**.
- **Sanitation:** During the winter, manually **cutting out and burning** the conspicuous silken communal nests while wearing protective gloves and clothing.
- Application of *Bacillus thuringiensis* (Bt) to young larvae in the spring before the population reaches damaging levels.
Conservation and Research
Research focuses on the chemical composition of the urticating hairs and effective, non-chemical methods for protecting sensitive human populations in areas with high infestation.