Bagworms in the “dunce cap” stage.  B. t. and Conserve provide good control at this stage.

Bagworm infestation with bags already drooping down.

Damage from bagworm feeding (Photo by: T. Simms).

Bag with green foliage incorporated into it suggests a live caterpillar inside the bag.  Insect growth regulators (Dimilin or Confirm), Acelepryn, Conserve (depending on bag/caterpillar size and population density) pyrethroids, acephate or carbaryl provide good control against larger caterpillars.  Caterpillar feeding is usually finished by mid-August, consequently hand picking in September – May is a good method to reduce next season’s populations.  Photos provided by:  Brian Kunkel, University of Delaware