Squash Bug Fast Facts:
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.
Squash bug's preferred food: yellow crookneck and/or yellow straight neck squash.
Generations per year: usually one, up to two in the Southern US.
Eggs: Yellow to bronze in color and deposited on underside of leaves along leaf veins in groups of a dozen or more.
Squash Bugs are a garden insect pest that seem to drive many people right to the brink of insanity. They are willing to feed on any member of the cucurbit family and feel free to help themselves to your cucumbers, summer and winter squash and pumpkins. Once they have sucked the juices from these plants, the vines often turn black and die back. To add insult to injury, squash bugs will feed on the actual fruit of the plant once they have become bored with feeding on the foliage.
It is possible to control squash bugs in your organic garden. Careful planning will be the key to your success. There are several modes of attack that can be incorporated into your plan. These include altering your planting dates or your use of certain plant varieties, mulching and tillage practices.
Squash bugs seem to prefer yellow summer squash and winter squashes such as Hubbard and some types of pumpkins to cucumbers or melons. So, if growing the perfect pumpkin isn't one of your garden goals, you can save yourself a lot of heartache by not planting them and spending your effort on cucumbers or melons instead. If winter squash is a must in your organic garden, then try planting varieties that have shown resistance to squash bugs. These include Butternut and Royal Acorn. Squash bugs prefer yellow summer squash to zucchini or patty pan summer squashes, so if you're not particular about the types of summer squash you grow, stick with the ones that the bugs like least. Hello Zukes!
Some studies have shown that companion planting and/or trap cropping (growing the bug's favorite foods in order to lure them away from your garden crops and into the "trap crop where you will catch and destroy them) can provide some control as well. 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.
Careful variety selection (or avoidance) combined with companion planting will help with your squash bug problem but, unfortunately, probably won't make it disappear. Planting your squash later in the season, once the majority of the squash bugs have already hatched and perished (or moved to your neighbor's garden.) can help you gain the upper hand against these pests. If this isn't possible due to the short length of your growing season or isn't effective because you live in the South, where squash bugs have two generations a year, 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 well fed (with compost and/or other organic fertilizers), and watered can help them fight off the squash bugs.
Squash bugs do have natural enemies in the form of insects that feed on them (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. Therefore, these beneficial insects may help you have fewer squash bugs next year but probably won't help you very much when it comes to saving this year's crop.
Once this year's squash has finished its season, be sure to clean up after it properly. Tilling your squash patch and/or removing the spent squash plants and composting them will bury and/or kill many of the surviving adults squash bugs and will eliminate the winter homes (leaf litter, weed cover) of many others.
Choosing your plant varieties and garden layout carefully, keeping your plants and soil healthy, providing a pesticide-free habitat for beneficial insects and doing a thorough garden clean up in the fall will give you great results. Then, as you enter your beautiful pumpkins in this year's fair or enjoy a well-earned bite of sweet, organic, winter squash, congratulate yourself for a job well-done.