We know ads can be annoying, but they’re what allow us to make all of wikiHow available for free. I lost a few of my trees because of them. The worm expels refuse through a small opening at the narrow, lower end of the bag and uses a wider opening at the to… Arborvitae and red cedar are the favored host trees of the evergreen bagworm, but cypress, juniper, pine, spruce, apple, birch, black locust, elm, maple, poplar, oak, sycamore, willow, and over 100 other species are also attacked. The trunk seldom exceeds 3 feet in diameter, helping give credence to its “pencil-like” appearance. Two types of parasitic wasps attack the caterpillars and help keep their populations under control. North Carolina State University Cooperative Extension: Christmas Tree Notes: Leyland Cypress, Clemson Cooperative Extension: Leyland Cypress, Clemson Cooperative Extension: Leyland Cypress Diseases & Insect Pests, North Carolina State University Cooperative Extension: Bagworms, PennState Woody Ornamental Integrated Pest Management: Bagworm Fact Sheet, University of Illinois Extension: Bagworms. wikiHow marks an article as reader-approved once it receives enough positive feedback. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/2\/25\/Get-Rid-of-Bagworms-Step-1.jpg\/v4-460px-Get-Rid-of-Bagworms-Step-1.jpg","bigUrl":"\/images\/thumb\/2\/25\/Get-Rid-of-Bagworms-Step-1.jpg\/aid4063687-v4-728px-Get-Rid-of-Bagworms-Step-1.jpg","smallWidth":460,"smallHeight":345,"bigWidth":"728","bigHeight":"546","licensing":"