Tent Caterpillar Season

Home Grown  by Keith Reed
If you remember last fall, many of our landscape trees (especially pecans) were hit hard with very high numbers of webworms. If you look closely, you can still see evidence of those webs in a few trees. If you look even closer, you’ll see that these trees are putting new leaves on and look just fine.

While it can be difficult to make blanket statements that cover all landscape situations, this is a good example of one that will usually hold up: Damage from leaf-chewing insects rarely causes any long-term harm to well-established trees and shrubs.

It looks like we may have a very similar situation unfolding this spring. We are seeing high populations of tent caterpillars on a few plants. Tent caterpillars are not the same species as webworms so large numbers of one does not necessarily mean large numbers of the other; it just worked out that way this year.

Tent caterpillars foods of choice are plums, cherries, crabapples, willows and birch but they will feed on many other species if they get hungry enough. If you are depending on a fruit crop or are concerned about the appearance of very large numbers of caterpillars on your ornamental plants, it would probably be a good idea to scout now for signs of these pests.

Once the caterpillars get their “tents” well established, it is very difficult to control them with insecticides so early treatment is important for best success. If you wish to treat after the tents are well-formed, you’ll need to disrupt the nearly waterproof tent for the products to be effective.

Speaking of tent disruption, be prepared for what you’ll find when you do this. Hundreds of insects can be hidden in a tent no larger than the size of a cereal bowl. If you are not a fan of insects, it can be a little disconcerting.

There are a number of insecticides (both synthetic and organic) that will control these pests. As always, please be careful to read the label and use the product according to the instructions. Reading the label not only provides the best opportunity for good control of the pest, it also protects you as well as the environment.

OSU has a very good
Pest E-Alert available that includes information on this subject (starting on page 5) including detailed insecticide information as well as good photographs to help with identification. You can also contact our office (see below) if you would like a copy.

For more information of this or any other horticultural topic, you can contact Keith Reed, the Horticulturist in the Payne County Extension office. Keith can be reached via email at keith.reed@okstate.edu, phone at 405-747-8320, or in person at the Payne County Extension office, located at 315 W. 6th in Stillwater.

Oklahoma State University, in compliance with Title VI and VII of the Civil Rights Act of 1964, Executive Order 11246 as amended, Title IX of the Education Amendments of 1972, Americans with Disabilities Act of 1990, and other federal laws and regulations, does not discriminate on the basis of race, color, national origin, gender, age, religion, disability, or status as a veteran in any of its policies
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