What You Should Know About Bagworms
Spring has arrived and with it comes an urge to get outside and enjoy the warmer weather. While you are out doing springtime chores in your yard, you may want to take a moment to inspect your shrubs and trees for the presence of bagworms.
Bagworms (Thyridopteryx Ephemeraeformis) are a species of moth most easily recognized by the cone-shaped case or cocoon-like bag that the caterpillar forms and hangs from the ornamental plant on which it feeds. Bagworms are native pests that are found throughout the United States. Their common host plants include evergreens such as arborvitae, juniper, spruce, cedar, pine and fir, as well as many deciduous trees and shrubs such as birch, boxelder, sycamore, maple and sweet gum.
Bagworm larvae feed on the upper layer of leaves, and can progressively defoliate an entire tree if the infestation is severe. Deciduous trees may be severely damaged and evergreens may be destroyed completely by such an infestation.
The worms begin to hatch in late May to early June in the Mid-Atlantic States. If you discover bagworms on a tree in your yard in the spring, you may be able to remove the bags from the tree by hand before any serious damage is done to the plant. Make sure to dispose of the bags by dropping them into a container of soapy water. Do not discard them on the ground because the eggs may survive and go on to infest nearby trees.
Bagworms have some natural predators including some species of birds and insects, and there is a species of wasp that parasitizes the bagworm by laying their eggs inside the bagworm larvae. You can attract these beneficial wasps to your garden by planting pollen and nectar producing flowers such as Shasta daisies and New England Asters. If you choose to use chemical pesticides be sure they are labeled to treat bagworms. Be certain to read the label and follow the instructions carefully. Chemical control will be most effective if applied just after the larvae have emerged from the bag in the spring (late May or early June in our area).
Rutgers Fact Sheet FS1144, Bagworms by George H. Daniel, Master Gardener, Somerset County, Nicholas Polanin, Agriculture and Resource Management Agent, Somerset County and Richard J. Buckley, Director, Rutgers Plant Diagnostic Laboratory is available at the Extension Center or on-line at http://njaes.rutgers.
If you have any questions please feel free to contact the Rutgers Master Gardeners of Cumberland County through our telephone help line at: 451-2800, ext. 4 or stop by Cooperative Extension of Cumberland County at 291 Morton Ave., Deerfield Township.