Walnut Caterpillars Defoliating Pecans: Identification and Control

Pecan Leaves Eaten, No Webs: Walnut Caterpillars

Clusters of caterpillars eating leaves without webbing, arching head/tail when disturbed, molting on trunks in furry patches—classic walnut caterpillar (Datana integerrima).

Control

• Spray young caterpillars with Bacillus thuringiensis (Bt), spinosad, carbaryl (Sevin), malathion, or acephate (Orthene).
• Target trunks during molting migrations—caterpillars congregate there.
• Large trees may need commercial applicator with high-pressure sprayer.

Life Cycle Note

They drop to ground to pupate in soil (no cocoon). One generation per year in north; two in south.

Resource

UGA pecan IPM guide on walnut caterpillars.