David Owens, Extension Entomologist, owensd@udel.edu
Congratulations to John Hochmuth for correctly identifying last week’s challenge as a young bagworm. This is the best time to treat for bagworm, particularly in windbreak trees that have had them previously.
This from Brian Kunkel in the Ornamentals Hotline:
First instars feed in the “dunce cap” stage. Named because the bag is carried in an upright position relative to the caterpillar. Scout for this life stage throughout June because eggs hatch over a 3-4-week period. There is one bagworm generation per year. Smaller bagworms are more susceptible to products that have less impact on generalist arthropod predators.
Physically removing bagworms is one method of control; however, this can get too labor intensive or impractical depending on the size or number of the plants or the size of the bagworm population. Companion plants encourage parasitoids to remain in the area to attack bagworm pupae. Pesticide applications targeting early instars are generally more effective than targeting larger bagworms. Products available for control include Acelepryn, Dipel, Confirm, Orthene, Tempo, Permethrin Pro, or other pyrethroids.
