black headed green larvae eating quaking aspen leaves

Asked May 30, 2013, 6:05 PM EDT

Greetings! My Montessori students have found a pest that is skeletonizing the leaves of a quaking aspen. The small worm like larvae are light green with a black head and when at rest have their rear ends in the elevated. The are about one to two centimeters in size with tiny black dots near their legs. We are stumped and looking for some help identifying this pest. We would like to turn this into a a research project that uses the scientific method. We want to find a natural way of protecting the leaves (even if only for a short time) without using harmful insecticides. Any leads would be appreciated...

Klickitat County Washington trees and shrubs insect issues horticulture

2 Responses

They look like tent caterpillars but let me know if you notice some silk around them. Regardless, if you want to use some biological control to control them I would suggest baculoviruses. Also the microbial insecticide Bacillus thuringiensis (Dipel, Thuricide,
etc.) can be an effective and selective control of all the tent-making
caterpillars. However, Bt must be eaten by the insect. Therefore, it must be applied before the colony covers all of the leaves. Just some ideas but if you can send me a new picture of the growing larvae.

Thank you for your response. I do not believe that they are tent caterpillars because there was no sign of silk on the leaves or anywhere on the quaking aspen. I also noticed they are not on the surrounding plants or trees. It seems to be specific to the aspen tree which is an ornamental, not indigenous. I am not able to get anymore pictures. If you think of anything else it could be please let us know!