Squash Bug Management
Squash bugs, insects that attack not only squash, but pumpkin, watermelon, cantaloupe, and cucumber are a significant garden problem. If you have had squash bugs recently, you can count on having them again this year. Consider these factors to increase your odds of successfully dealing with this troublesome pest.
Let’s begin with the life cycle. The true key to successful management is not to completely eliminate this pest, but to manage the populations. Early success will pay big dividends. Squash bugs can overwinter as adults in last year’s plant debris. This makes fall garden cleanup for these crops especially important. This is your first line of defense. When the adults begin laying eggs in late April-early May, simply crushing or otherwise disposing of the egg clusters is your second most effective control method. The bugs hatch as small green nymphs (looking nothing like the adults). It is at this point that chemical control will be most effective. We’ll talk more about that at the end of this article.
As squash bugs begin to grow and feed, they like to seek shelter around the base of the plant and dark areas. Another successful control strategy is to place a few boards near the plants to take advantage of this behavior. The bugs will collect under them at night and you can easily collect or kill them early in the morning simply by flipping the boards over. The base of the plant is also a good spot to place a non-chemical control option; sprinkle diatomaceous earth around so the nymphs will come in contact with the product as they come and go off the plant. The diatomaceous earth doesn’t poison the insect, but disrupts its outer protective layer and it simply dries up.
We are discussing the pesticide control options last because if that is the only step you take, you will almost certainly be unsuccessful! It is difficult to give exact pesticide recommendations because the choice of products on the market varies greatly in their percentage of active ingredient and formulation method. However, looking for the following active ingredients and carefully following the label instructions on the packaging will give you your best opportunity for success: spinosad, cyfluthrin, pyrethrins and carbaryl. Please note that most insecticides are broad spectrum, meaning they will kill more than just squash bugs. If chemical control is used (even those considered organic), please follow the label directions carefully to avoid harming bees and other pollinators.
One last word about using pesticides. Using the same product over and over can quickly lead to an insect population that is resistant to the insecticide. Choose at least two from the listed options and rotate between them for best long-term success.
The information presented is a summary of OSU Pest E-Alert, Vol. 13, No. 22. For a copy of the complete report or more information on any other horticultural topic, you can contact Keith Reed, the Horticulturist in the Payne County Extension office. Keith can be reached via email at firstname.lastname@example.org, phone at 405-747-8320, or in person at the Payne County Extension office, located at 315 W. 6th in Stillwater.
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