Hello!

The item in the photo is a bagworm. From late June to mid-August, the caterpillars inside the silk bag had their head sticking out the top end as they crawled on the nearby tree and ate the needles. Bagworm defoliation can cause massive needle loss that turns the tree brown and may lead to the death of the plant.

When the caterpillars are grown, they tie the bag to a twig or nearby structure, seal the bag shut and pupate in preparation for metamorphosis to the adult moth.

The suggested control is to pick bags off lightly-infested trees and shrubs over the winter. Heavily infested plants may need to be removed and replaced.

Please see our online article at https://hortnews.extension.iastate.edu/bagworm

Thanks.

Donald Lewis

Donald R. Lewis | Department of Entomology
Iowa State University Extension and Outreach

Extension Entomologist