Adult squash bugs are about 5/8” long and 1/4” wide. They are grey or black and have orange and brown stripes on the edges of their abdomen. Their eggs are a yellow to bronze (they look red to me) in color and are deposited on underside of leaves along leaf veins in groups of a dozen or more.
Squash bugs feed on cucumbers, summer and winter squash and pumpkins, although their preferred food is yellow crookneck or yellow straight-neck squash. Once they have sucked the juices from these plants, the vines often turn black and die back. When that is done, they will start on the vegetables from the plant. I hate them, as it seems like they are all over everything once they come.
Varieties that have shown resistance to squash bugs are Butternut and Royal Acorn. Squash bugs also prefer yellow summer squash to zucchini, so you could try just planting those 3 varieties. Plants that are purported to repel squash bugs to some degree are catnip, tansy, radishes, nasturtiums, marigolds, bee balm and mint. These can be planted near your squash plants with the goal of keeping squash bugs from finding a home in your organic garden.
For control, you can try using floating row cover to keep these pests off your plants. Using floating row cover (a gauzy, see-through blanket that goes over your plants) and keeping your plants watered and well-fed with compost or other organic fertilizers can help them fight off the squash bugs.
Squash bugs do have natural enemies in the form of insects that feed on them, such as spiders and ground beetles, and diseases that strike them. Tachinid flies and some parasitic wasps prey on squash bugs by laying their eggs in them. However, affected bugs often continue to feed and lay eggs for a while after being parasitized. These beneficial insects may help you have fewer squash bugs next year, but they probably won’t help you very much when it comes to saving this year’s crop.
Tilling your squash patch or removing the spent squash plants and composting them at the end of the season will bury or kill many of the surviving adult squash bugs and eliminate the winter homes of many others, which will help control the next year’s population. Next week – Cucumber Beetles!