Is There Anything That Will Control Squash Bugs?

Q. I live in southern Utah "Cedar City" and put in a garden that is 15x120 each year. Over the years the squash bug infestation has become worse and worse.
I used Sevin insecticide in both the powder and liquid spray form and tried a product called Bug B Gone. All this seems to help some but the bugs always come back. Last year they got so bad that I got a bottle of Sevin that you connect a garden hose and sprayed the entire garden but they still came back.

Brave squash bugs out in the open on this squash plant

A. The biggest problem with gardens and squash bugs is that people don’t get on top of the problem early enough. They wait until they see squash plants, melons and pumpkins start to wilt before they go and investigate the problem. When they then check under the leaves they see hundreds of them in all stages of development and by that time it is normally too late.

Squash bugs begin to infest these types of plants when they are very young. You can have a fairly large population feeding on the undersides of leaves and not see any reaction by the plants until the numbers are very high.

Squash bugs with yellowing and browning starting from their feeding

It is important to check the leaf undersides two or three times a week. Once they are spotted it is important to get rid of them by handpicking or a cordless vacuum if you are squeamish about them.

Soap and water sprays will work but they must be sprayed on the undersides of the leaves, not the tops of leaves, for it to work. Soap and water sprays like insecticidal soaps are effective but the bugs must be sprayed with the soapy solution directly for it to work. The soap sprays do not leave enough of a toxic residue behind to give any long lasting control. So sprays must be quite often during the week.

Mama and babies and the yellowing from feeding damage

Some people have reported some damage to plants from soap sprays made from dishwater liquid detergents so it is best to buy an insecticidal soap like Safers or make sure the soap you use is safe to spray on plants. Other insecticides like Sevin are also very effective but they are also toxic to bees, not a good mix with plants that are in flower.

If you lay boards or thick cardboard in the garden they will congregate under there and can serve as a good trap that where you can get rid of them by hand. This does not substitute for checking under the leaves.

Melons and squash that vine can also be trellised and when they are trellised they are easier to check, spray and hand pick and seem to not get infestations that are as heavy as those that lay on the ground.