Identifying and Controlling Petunia Pests: Hornworms vs. Flea Beetles

Black spots and sticky leaves on petunias usually mean one of two pests:

1. Hornworm caterpillars – black droppings, no leaf eating. Moths lay eggs at night.
2. Potato flea beetles – tiny jumping beetles that chew holes; larvae eat roots.

Insecticidal soap kills both but also beneficials. Better: Bacillus thuringiensis (Bt) kurstaki/aizawi (Dipel DF, XenTari) for caterpillars, or spinosad (Entrust) for broader control. Check local registration.