Bagworm caterpillars live their entire life inside their protective case (bag) and can become a serious problem for your evergreen if left uncontrolled.

You can control bagworms in basically two ways:

  1. If the entire evergreen is reachable with a ladder, you can pick off the bagworm sacks and throw them away in the trash. This needs to be done in the winter or before the first of June.
  2. If the tree is too large for this, you will have to resort to spraying your tree with an insecticidelike Earl May Eight. Earl May Eight comes in a variety of application methods, so choose the one that works best for you. New bagworms hatch about mid-June, so this is the time to be watching for caterpillar activity and spraying once a week until it stops. It’s best to control bagworms when they are young and small in size because controls become less effective as their size increases.

The best way to avoid problems on your spruce is to keep them watered and fertilized to promote plant health.