Bagworms

• Adult male bagworms are clear-winged moths with dark, hairy bodies and 1-inch wingspans. The females, which are legless, wingless, and yellowish in color, spend their entire lives in cone-shaped bags made from silk and plant parts. After mating, the females lay between 500 and 1,000 eggs in their bags and then die. The emerging larvae, which are between 0.18 and 2 inches long, create their own bags shortly after hatching.
  
  

Effects

• Bagworm larvae carry their bags with them as they feed on Leyland cypress needles and defoliate the trees. Mild infestations stunt tree growth, but severe infestations can kill trees in only one or two seasons. The damage is more evident in landscapes than in forested areas.
  
  

Prevention/Solution

• Bagworm populations are controlled by manually removing the bags. Bacillus thuringiensis ("Bt"), a bacterial insecticide, contains a bacterium that sickens and kills young bagworm larvae. Traditional insecticides such as carbaryl and permethrin also can help control bagworm outbreaks.