Crop & Pest Report

Accessibility


| Share

Tent Caterpillars are Feeding on Chokecherry and Other Trees (05/24/18)

Eastern tent caterpillars (Malacosoma americanum) and forest tent caterpillars (Malacosoma disstria) are feeding on tree foliage now.

Tent Caterpillars are Feeding on Chokecherry and Other Trees

Eastern tent caterpillars (Malacosoma americanum) and forest tent caterpillars (Malacosoma disstria) are feeding on tree foliage now. Eastern tent caterpillars make the webbed tents in the forks of tree branches, which are used as shelters and resting places. The forest tent caterpillar does not make any webbed tents, but they wander around in masses of larvae and crawl over trees, picnic tables, patios, lawns, etc. which people consider extremely objectionable. Fortunately, they do not bite. Large numbers of forest tent caterpillars crushed on roads causes the roadway surfaces to become greasy and slippery. They infest many trees hosts: ash, aspen, basswood, birch, chokecherry, cottonwood, elm, maple, oak, pin cherry, poplar, and other hardwoods.

One generation per year occurs for either species. Both overwinter as eggs. Larvae hatch is in early spring. For the forest tent caterpillar, larvae are easily identified by the keyhole shaped spots along their backs and broad bluish lateral bands. For the eastern tent caterpillar, larvae are black and somewhat hairy with a whitish-yellow stripe down the middle of the back, narrow broken orange-colored subdorsal stripes, and lateral white and blue markings. In five to six weeks, the larvae pass through five larval instars and are about 2 inches long. Mature larvae then form silken cocoons to pupate. Adult moths will emerge from cocoons during early summer (late June or early July).

knodel johnson

Management: Bt (or Bacillus thuringiensis var. kurstaki; Dipel, Thuricide), a natural occurring soil bacterium, works well to control young caterpillars and conserves beneficial insects. Other insecticides available to homeowners include: acephate (Orthene), azadiracthin (Azatin), carbaryl (Sevin), esfenvalerate (Bug-B-Gon), malathion, permethrin, spinosad (Conserve), or other insecticides registered for trees. Always read, understand and follow the insecticide label directions.

 

Lezlee Johnson

North Dakota Forest Service

Forest Health Manager

 

Janet J. Knodel

Extension Entomologist


This site is supported in part by the Crop Protection and Pest Management Program [grant no. 2017-70006-27144/accession 1013592] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed are those of the website author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

USDA logo

Creative Commons License
Feel free to use and share this content, but please do so under the conditions of our Creative Commons license and our Rules for Use. Thanks.