My tree was hit with bagworms

Asked February 23, 2020, 5:30 PM EST

My tree was hit with bagworms and turned brown. Will it recover? How do I care for it? Thanks.

Hanover County Virginia

1 Response

Bagworms can feed on many plant species but are most common on conifers such as Leland cypress, arborvitae, cedar, juniper, and pine. Unfortunately, this tree will not recover. You should be concerned with the other trees around it. Female bagworms lay 500-1,000 eggs in their bag before they die in the fall. The eggs overwinter and hatch in May and June. The newly hatched larvae crawl to foliage to feed or spin down on silken threads that are blown about in the wind. This behavior is called 'ballooning' and helps bagworms get to new plants. During August and September, adult bagworms emerge as moths from the pupal case. Females are flightless and never leave the bag so male moths emerge from their bags in search of females to mate with. Mating occurs through New bagworm infestations often go unnoticed until late in the summer when caterpillars are large and consuming a lot of plant material and branches begin to appear defoliated. Scout for bags in winter. The brown bags are easy to see against evergreen foliage. Since the bags contain eggs any tree with bags will have bagworms the following spring. Thus the same trees and shrubs will be damaged year after year as populations build. Monitor bagworm emergence in spring since small caterpillars are easier to kill with insecticides and haven't caused much damage yet.the bag. After mating, females lay their eggs inside the pupal cast skins and die.

Late May or early June is a perfect time to spray for bagworms as then the caterpillars are tiny and very susceptible to pesticides. At that time, use a pyrethroid such as permethrin or bifenthrin because pyrethroids have a longer residual life than most other insecticides. These pesticides are readily available at most garden centers and big box stores.