The chadokuga (チャドクガ, literally "tea poison moth"), Euproctis pseudoconspersa (tea tussock moth, family Lymantriidae), is a Japanese moth whose caterpillars are a notorious local hazard. The final-instar larva is about 27 mm long, pale yellow-brown with a row of black tubercles and a white lateral stripe, and it lives in groups, neatly lined up feeding on the leaves of tea (Camellia sinensis) and other Camellia-family plants such as camellia and osmanthus. Its real danger is not the visible long hairs but 300,000–500,000 microscopic barbed stinging setae (about 0.1 mm each) clustered on the black tubercles. These detach on contact with skin or clothing — or drift on the wind — and cause painful, itchy dermatitis, with welts appearing within 2–3 hours and a delayed rash 1–2 days later. The stinging hairs persist on eggs, cocoons, shed skins, and even the adult female's tail, so people can be stung during winter pruning without realizing it.
Key facts:
- Distribution: Japan (Honshu southward), plus Korea, China, and Taiwan
- Generations: two per year; larvae emerge April–May and August–September; adults in June–July and October
- Overwintering stage: eggs
•Treatment: peel off embedded hairs with tape, wash with soap and water, and see a dermatologist if itching persists
