How to Identify and Control Bagworms

Defoliation may affect the trees in your landscape if bagworms are not controlled.

Bagworms are not difficult to identify, but require the correct timing to control them effectively. The insects create spindle or carrot-shaped bags that hang from the tree limbs. The bags look like a natural-looking Christmas ornament. Bags protect the worms from birds and other predators.The insects affect cedar, juniper, white pine and many other shrubs and trees. Considerable damage may result in defoliation of the plants during the summer.

Things You'll Need

• Bucket
• Liquid dishwashing soap
• Insecticides

Instructions

1. Pluck the carrot-shaped bag off the tree limbs at the part that connects to the branch. Drop them into a bucket of soapy water to destroy the insects. This is most effective before the eggs hatch in early June. Another option is to dump the bagworms in a sealed plastic bag and deposit them in an outdoor trash can. Removing the bagworms may be impractical and dangerous in large trees.

2. Spray the trees with biorational pesticides, such as Chlorantraniliprol, Indoxacarb, Spinosad and Tebufenozide. They destroy the bagworms without killing beneficial insects. Saturate the limbs and foliage well, because the caterpillars must ingest the insecticide for it to work.

3. Apply dinotefuran to the soil around the base of the tree in early May. This allows time for the insecticide to get into the leaves before the worms hatch. Once the young bagworms ingest the leaves, they will die.

Tips & Warnings

• Inspect your trees on a regular basis for bagworms. The female bagworm is wingless and never leaves the safety of the bag. The winged male fertilizes the bag. One female bag can produce as many as 1000 bagworms, according to the Purdue University website.

References

• Purdue University; Bagworms; Timothy J. Gibb; November 2009
• University of Tennessee; The Bagworm and Its Control; Frank A. Hale;