Mulch plants properly and provide adequate water during dry periods. Pruning wounds may be sprayed with a thiophanate-methyl fungicide. Read and follow all label directions. Damage to plants results from feeding by the caterpillar, which causes loss of needles. Mild infestations of this pest slow the growth of Leyland cypress.
Heavy infestations can kill a plant.
The adult female is yellow and appears almost maggotlike. The bag is formed from silk that the larva produces. As it feeds, the larva adds bits of plant material to the bag. The bag is about 2 inches when complete. In South Carolina, bagworms survive the winter as eggs in a bag.