Bagworms, which will later turn into black bagworm moths are native to North America and more specifically to East Coast. Bagworms eat over 120 types of trees, the ones they enjoy the most are evergreens, like juniper, arborvitae, cedar, and spruce.  On deciduous trees, those that shed their leaves in the fall, bagworms chew small holes in the leaves and can cause defoliation. If you can get rid of the bagworms, these trees will bounce back. Their chewing is bad enough, but they also wrap silk around the twigs they build their bags on, which could kill the tree twigs a few years from now.

The life cycle of the bagworm caterpillar is broken down into 4 stages: egg, larvae, pupal, and adult. The damage is done during the larva stage, while the caterpillars are actively feeding on needles and branches of trees. The Bagworm has a voracious appetite and is a serious pest. As well, the silk the caterpillars use is so strong it can strangle and kill the branch it hangs from over the course of several years as the branch grows. They’re called “bagworms” because after the larvae feed on evergreens and other trees, they swaddle themselves in cocoon-like “bags” constructed from twigs, leaves, and self-spun silk. Once in its bag, a female bagworm can lay 500 to 1,000 eggs, escalating your bagworm problem to a serious infestation very quickly.

As the bagworm grows, the bag that contains them grows as well, as they will add leaf fragments to the outside of the bag for camouflage. The bags look like baseball bat-shaped baubles hanging from the tree. The bags of these insects hang from slender twigs and branches on trees and are generally hidden by foliage. Bagworm nests are usually brow or gray in color and look like small pinecones.

There is one way to know if your cedar tree has bagworms. If you see little cone shaped things on your cedar tree, more than likely you have bagworms. Cedar trees do not produce cones. The damage done to conifers takes longer to heal as their recovery happens as they continue to grow from their tips, and eventually new growth will cover the damage. It can take years for them to regain their appearance. Heavily infested conifers or evergreens take on a brown tint.

Getting rid of bagworms takes work on your part:

  • Check and lift branches looking for bagworm egg sacks
  • Clip off the sacks, dropping them into a bucket of soapy water.
  • Put or pour the soaked bagworms into a sealed plastic bag and throw it out with the trash.

Ideally, bagworm control should be done in the late fall or very beginning of spring. At that time, unhatched eggs will still be inside the bag and can be effectively coated. Dish soap will work just as well as any chemically manufactured insecticide. Repeat this procedure every fall, winter, and early spring to reduce bagworm populations before the eggs hatch. Or call the professionals at Precision Tree and Landscaping Services to help solve the bagworm issue before they negatively affect your trees.