Tobacco budworm damage being seen on bedding plants

Tobacco budworm is not usually a pest of greenhouses crops. However, Univ. of Mass. floriculture extension specialist Tina Smith said consumers in the Northeast are seeing symptoms of damage caused by budworms on petunias, geraniums and nicotiana. Caterpillars attack the flower buds which fail to open. Petals of emerged flowers are also chewed, giving the flowers a ragged appearance. The amount of damage progresses through the growing season, becoming most noticeable during late summer.
The caterpillars become full-grown in about a month, drop to the soil and pupate. Adults emerge to repeat the cycle, with two generations normally produced each year in the Northeast.
Larvae are most active during dusk and best discovered at this time. During daylight hours, they often hide around the base of the plant.
Insecticides containing the active ingredient spinosad may provide control. Insecticides containing Bacillus thuringiensis (Bt), including Thuricide, Deliver, Dipel, are effective biological controls on petunia where caterpillars eat the blossoms. On geraniums, where the caterpillars drill into the buds and eat little of the outside surface, Bt may not provide control since it must be ingested to be effective.