Tobacco budworm
A 1 to 1.5 inch caterpillar in green, pink, brown, or near-black, with thin pale stripes running along the body. Hides deep inside flower buds and old spent blooms during the day. Active at night. The signature petunia pest by a wide margin.
Petunias bloom fresh in the morning then look shredded by evening. Round holes chewed through unopened buds. Petals come out ragged or full of holes when the flower opens. Tiny dark green or black pellet droppings on lower leaves and on the soil are a giveaway.
Hand-pick at dusk and pinch off infested buds
Walk the bed or container an hour after sunset with a flashlight. Look inside fresh buds and inside spent blooms still hanging on the plant.
Pinch off any bud or old bloom with a hole. The caterpillar is usually inside. Drop the whole thing in a jar of soapy water.
Repeat every 2 to 3 nights through July, August, and September. The moths lay new eggs all summer.
Spinosad spray on buds and new growth, weekly for 4 weeks
Spray spinosad (Captain Jack's Deadbug Brew or Monterey Garden Insect Spray, ~$12 to $15) over the whole plant at dusk, getting the spray down into open buds. Spinosad reaches caterpillars feeding on bud tissue and breaks down in sunlight, so dusk timing matters. Repeat every 7 days for 4 weeks. Bt does not work well on tobacco budworm because they tunnel inside buds before eating much surface tissue.
Deadhead spent blooms every 2 to 3 days
Pinch off every faded bloom into a bag, not onto the soil. Tobacco budworm caterpillars often hide inside old blooms during the day and come out at night to chew fresh buds. Removing spent blooms removes their daytime shelter and pushes more new flowers at the same time. Bag and trash, do not compost.
