Webworms (…and bagworms)

Webworms or bagworms…which do you really have?  Many people have been asking me about “bagworms” as of late, but after asking a few questions I discover that they have webworms.  So, what’s the difference?


  • Form small cases that hold larvae, pupae, or female adults and eggs
  • Cases are often found on evergreen trees & shrubs such as cedar, juniper, cypress, or pine
  • Cases are made from silk and plant material laid down similar to shingles on a house, overlapping in layers
  • Newly hatched larvae spin a silken thread & either are carried to a new plant by wind or attach themselves to the plant they are on and begin to build their own silken bag
  • Bags remain on plants even if bagworms are dead
  • Bags are transportable; larvae carry them along as they move about the plant
  • To manage bagworms, handpick bags off the plant and dispose of them





  • Spin webbing over branches of host tree to enclose foliage they feed upon
  • Attack over 88 species of plants, including fruit, nut, and ornamental trees and shrubs
  • Use web as a protective covering; spin webbing immediately after hatching out of egg
  • Webbing remains on tree even if caterpillars are dead/ no longer there
  • Webs can be pruned out of the tree or opened with a stick/ spray of water to allow predators to eat caterpillars
  • When using a pesticide, webbing still needs to be opened

Comments are closed.