Bagworm Scavenger Hunt


BagwormsI’ve long been resigned to the fact that pests and diseases are as much a part of the gardening experience as beautiful flowers and bountiful harvests, but that doesn’t make the problems any easier. Such was the case when I recently discovered signs of bagworms.

As I was strolling through the garden last week I noticed what looked like several tear-drop shaped clumps of dead foliage hanging from the branches of my arborvitaes. My heart sank as I realized they were bagworms – those voracious caterpillars that feed on the foliage of trees and shrubs, weaving little cocoons out of their silk and bits of dead leaves. I had already lost one of the trees to drought; I sure wasn’t going to let an infestation of bagworms take out the remaining two.

And that’s the kicker about bagworms; they can defoliate a tree pretty quickly. By the time you notice their damage, it may be too late.

I counted myself lucky that I caught the situation in late winter while the worms were still unhatched.

I started treatment for these pests by hand collecting the bags. Each bag contains 500 – 1000 eggs.

In addition to collecting the egg cases I knew I would also need to spray with an earth-friendly insecticide. The best time to spray is right after the bagworms hatch, but it can be tricky to know just when this happens. I decided to try a tip I recently read in the February issue of the American Nurseryman magazine about how to determine the best time to spray.

Bagworm Cocoons in a JarI put a few of the egg cases in a closed container and placed the container in a shady spot outside. It’s a control of sorts. I can watch the activity in the container and a few weeks after the eggs hatch and the baby worms begin making new bags, I’ll know to spray the trees to eliminate any of the bagworms that I might have missed.