Battling Bagworms in Southern Illinois

Filed under Plants, Misc by Lauren Cook on .

Have you seen any of these guys on your spruces or junipers this year?  

     (A bagworm cocoon)

      Bagworms can damage all kinds of plants, but they are most commonly found on needled evergreens. These pests remove needles/leaves from the host plant to create a cocoon that they will hibernate most of the year inside, only to emerge from dormancy the following spring to reproduce and cause more damage to the infected plant. Getting rid of bagworms can be difficult because there is only a small window in the spring where spraying insecticide will work to rid a plant of infestation. The months of May and June in southern Illinois are typically the months where bagworms are actively feeding on the host plant and a systemic insecticide will work to eradicate the problem. However, this year the warm weather has spread across southern Illinois earlier than usual, which may have brought the bagworms out of their protective cocoons sooner than normal. If you have seen bagworms recently on any of your landscape plants, you will want to do the following:

                                                                                                                (An active bagworm)

  • Remove all “bags” or cocoons from the plant and destroy them. Burning or smashing them is the best way to ensure that the bagworm inside will not survive until next spring.

  • Spray the infected plant with a systemic insecticide such as Sevin or Malathion. Follow the directions on the label and avoid spraying in the hot sun.


       If you discover bagworms on a plant during parts of the year where the bagworms are not actively feeding, it will still help to remove and destroy as many cocoons as possible. Then, make a mental note to check back on the plant in the spring for any feeding worms. At that point you can spray with a systemic insecticide.