Even the best gardeners are plagued with hard-to-control pests, and squash bugs are an insect that come back to battle every year.
Butternut squash are nearly ready for harvest in the Douglas County Master Gardener Demonstration Gardens, 2110 Harper St. Master Gardeners are just starting to find squash bugs, but you are welcome to look for them too if you make it out for a visit. The nearby shrub border is in full bloom, and the new shade garden offers a break from the summer sun.
A silver bullet for these persistent pests has yet to be found, but good cultural practices can help protect squash plants for a longer production season.
Lucinda McDaris, who gardens in rural southern Jefferson County, knows the bane of squash bugs well: Her squash crop was wiped out last season when the bugs moved into her garden.
This year, McDaris is working hard to stay ahead of the squash bugs and other pests. “I am pretty good about coming out and checking for bugs every night,” McDaris says. The “bad” bugs, like squash bugs, are collected and delivered to her chickens for the birds to eat. The night before I visited, McDaris said she collected a large handful of squash bugs and a few hundred striped blister beetles that are also moving through gardens right now.
Besides feeding them to the chickens, you can dispose of handpicked insects any way you see fit. Squash bugs can indeed be squashed, but avoid this action with blister beetles as they will cause just what their name implies.
Squash bugs use their piercing, sucking mouthparts to suck the juices (and the life) out of both plants and the squash itself. On the fruit, their feeding causes distortion and decreases the post-harvest shelf life. Squash bug feeding on foliage and stems makes leaves yellow, wilt and die.
Adult squash bugs are grey to brown (often indistinguishable on bare soil) with wings that partially cover a darker abdomen. They are more elongated than shield-shaped stinkbugs and can grow to up to three-fourths of an inch long. Baby squash bugs, called nymphs, are typically green to light gray and darken as they mature.
McDaris says she also looks for squash bug eggs, which typically appear in clusters on the undersides of leaves and are coppery in color. She tears out the little section of leaf they are attached to and destroys it to prevent the squash bug population from building.
This year McDaris put out boards around the squash plantings, which is a common recommendation in squash bug control. The idea is that the bugs will gather on the undersides of the boards and can easily be handpicked in nightly scouting.
“I don’t think it’s working,” McDaris confides. She has only found a few bugs on the boards in comparison with the bugs she has picked off the squash plants.
“I planted really late this year, too,” says McDaris, hoping she would be able to get some squash later in the season. “At some point, you eventually quit fighting them.”
K-State Research and Extension also recommends removing plant debris from the garden at the end of the season to reduce overwintering sites for squash bugs and rotating crops when possible. Cheesecloth, netting or row covers can be used to protect the plantings, but they must be removed often enough for bees to pollinate the flowers, so they are not always feasible.
There are a few species of beneficial insects that prey on squash bugs, including different parasitic wasps and tachinid flies. Beneficial insects can be purchased and released into the area but are often ineffective because they cannot be kept there.
Both organic and conventional insecticides are most effective on squash bug nymphs. Adult squash bugs have a thick exterior cuticle that protects them from insecticides, and eggs are also impervious. A number of insecticides are labeled for squash bug control, however. If you choose to use an insecticide, read the label to be sure squash bugs and the type of squash plant you want to protect are both listed on the label. Both conventional and organic insecticides can also kill bees that are necessary for pollination.
According to K-State Research and Extension, there are not known squash or pumpkin varieties that are resistant or immune to squash bug damage. A few types of squash have shown less damage from squash bugs in research trials than other varieties. The least damaged squash varieties are Butternut, Royal Acorn, Sweet Cheese, Green Striped Cushaw, Pink Banana and Black Zucchini.
Fighting squash bugs and other pests, keeping up with watering in the drought, and occasional visits from deer, raccoons, and the neighbor’s donkeys keep McDaris jumping.
“I work hard, I work a full-time job and this is almost a full-time job, too,” she says, “but I love it.”