Squash bugs — insects that attack not only squash, but pumpkin, watermelon, cantaloupe and cucumbers — have been a real problem for many years.
In order to understand how to conquer insects in plants, we must first understand the life cycle of the culprit. And the true key to successful management is not to eliminate the pest, but to manage the populations. Early scouting for insects is critical.
Squash bugs can overwinter as adults in last year’s plant debris. Fall garden cleanup for these crops is especially important; sanitation is your first line of defense. When the adults begin laying eggs in late April-early May, simply smooshing or otherwise disposing of the egg clusters is your second most effective control method. Just be aware, squash bugs hatch as small green nymphs looking nothing like the adults.
As squash bugs begin to grow and feed, they tend 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 the boards at night, and you can easily collect or kill them early in the morning when you flip over the boards. The base of the plant is also a great place to concentrate another organic control option, diatomaceous earth. Just sprinkle this around the base of the plant, and as the nymphs come and go off the plant, they will walk over the product. Diatomaceous earth works by absorbing the oils and fats from the cuticle of the insect’s exoskeleton, and its sharp edges are abrasive, causing the insect to desiccate and die.
Please note that most insecticides are broad spectrum, meaning they will kill more than just squash bugs. If you choose to use a chemical control method such as Spinosad, cyfluthrin, pyrethrin’s or carbaryl, read and follow the label directions carefully to avoid harming bees or other pollinators. Also, if you are using the same product over and over, it 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 control.