fbpx Map Marker Icon Phone Icon Email Icon

Tree Talk - Metropolitan Forestry Services

Our commitment to education, training, research and collaboration is important to us. Armed with proper information, you can prevent problems before they even begin!

View All Articles
June 15, 2023

Bagworm Explosion


Bagworm populations have increased tremendously in the last few years due to the unseasonably warm weather in late spring and early summer. This caused the bagworms to hatch in large numbers much earlier than expected. Hardest hit are the arborvitaes, junipers, and spruces.

Bagworms harm trees by eating the foliage, weakening the tree. They can do quick and lasting damage to a hedge or screen of evergreens in just 24 hours, so most people aren’t aware of the problem until it’s too late and the damage is done. If you or your neighbors found these little bundles on your trees, you will want to be proactive in the springtime to protect your trees.

Bagworms are easily controlled if sprayed when small but are much harder to control when mature. Bagworms emerge from their bags in May through mid-June and begin feeding voraciously, so June-July is the perfect time to spray for control. Remember to pick off all the teardrop shaped bags that you can see; leaving just one female bagworm on your plant can generate 150-350 offspring the following year.  Plants with light to moderate damage have a better chance of survival with deep root fertilization and supplemental watering.  Severely damaged plants will have to be replaced.

If you have had damage or suspect a problem, please give our arborists a call or email and we’d be happy to assist!

Check out the Missouri Botanical Garden for more information on bagworms.

The larvae’s bag is made from twigs and foliage.
Bagworm damage on an evergreen
Damage due to bagworm infestation – John C. French Sr., Retired, Universities: Auburn, GA, Clemson and U of MO
bagworm sac cut open to view eggs
Bagworm eggs – James B. Hanson, USDA Forest Service

Want More Tree Talk?

Thumbnail of the Spring 2018 Newsletter Issue View
Spring 2018
Thumbnail of the Spring 2016 Newsletter Issue View
Spring 2016
Thumbnail of the Spring 2015 Newsletter Issue View
Spring 2015
Thumbnail of the Summer 2012 Newsletter Issue View
Summer 2012
Thumbnail of the Winter/Spring 2012 Newsletter Issue View
Winter/Spring 2012
Thumbnail of the Summer/Fall 2011 Newsletter Issue View
Summer/Fall 2011
Thumbnail of the Summer 2010 Newsletter Issue View
Summer 2010
Thumbnail of the Winter/Spring 2010 Newsletter Issue View
Winter/Spring 2010
Thumbnail of the Summer/Fall 2009 Newsletter Issue View
Summer/Fall 2009

Our goal is to provide you with the best possible service. If you are not satisfied with any treatment or completed job, we will resolve the situation to your satisfaction. We want to do our utmost to ensure your trees and shrubs are always 'green and growing'.