Trees and Insects

Home Grown  by Keith Reed
As we have approached mid-July the last few years, we’ve been alerting clients to the possibility of large webworm outbreaks. We can’t say with any level of certainty just yet if they are going to be present in large numbers again this year, but early indicators are they might not be. Let’s hope that trend continues.

Regardless of how the webworm population does or does not develop this year, if you’re a regular follower of this column, you may remember that we seldom advise attempting to control these pests. While it’s no question that they are a visual nuisance, it is rare for them to cause long term problems for a tree.

If you have trees that have been hit hard by these pests the last few years, take a look at them now. How do they look? Assuming they are otherwise in good health, chances are there is no visible evidence of the webworms having attacked the plant. This is typical, not only for webworms, but most other insects that give homeowners cause for concern, redbud leaf-rollers being another recent example that produced hundreds of inquiries to our office.

The take home point here is to not over-react to an insect problem and reach for a pesticide as a first response when caring for mature trees and shrubs. Identify and/or research the pest and learn a bit about it before taking any more steps. Chances are good that the issue will work itself out with minimal inputs from you.

This being said, there are certain insect outbreaks that can require your attention to protect the long term integrity of the plant. A bagworm outbreak on a plant like a Leland cypress is a good example. If corrective action isn’t taken in this case, the plant could easily fail.

Pesticides are a valuable tool when used appropriately and applied correctly. However, they should only be used when necessary if we have expectations of seeing them remain available and valuable for our use.

Keith Reed is the Horticulture Educator in the Payne County Extension OSU Extension office. You can contact him via email at, call 405-747-8320, or stop by the Payne County Extension Office 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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