Pecan Walnut Caterpillars: Spray Young Larvae, Target Trunk

Pest ID

No webs, voracious leaf eating, clusters = walnut caterpillar (Datana integerrima). Not fall webworm. Arch head/tail when disturbed. Molt in groups on trunk (fur-like cast skins). Pupate in soil.

Control

1. Spray young larvae: Carbaryl (Sevin), malathion, diazinon, acephate (Orthene), Bt (Bacillus thuringiensis).
2. Thorough coverage: Leaves, twigs, limbs, trunk (they descend to molt/pupate).
3. Large trees: Commercial high-pressure sprayer needed.

Dog Safety

• Bt = safest for pets.
• Keep dogs off treated area until dry.
• Follow label re-entry intervals.

Trunk spray is strategic—catches them during group molt descent. Bt is pet-friendly and effective on young caterpillars.