COLUMN | Milkweed + Honey: How to manage squash bugs

Published 12:00 am Wednesday, August 23, 2023

“All that most maddens and torments; all that stirs up the lees of things; all truth with malice in it; and all that racks the sinews and cakes the brain; all the subtle demonisms of life and thought; all evil, to crazy Ahab, were visibly personified, and made practically available in Moby Dick.” — Herman Melville

There are three guarantees in this life: death, taxes, and squash bugs.

For three decades and more, I had managed to avoid two of the three. Until a fateful Monday, July 17, in the year 2023. As I stretched out my hand to pluck the first ripe zucchini of the summer, I saw a scurry. I saw a dark flash. He was there, amidst the spiky vines, and he was gone: a devil, a phantom, an imp.

Of course, my friends had warned me. I had heard the omens whispered among fellow gardeners. And now here he was, peering from under a leaf and then disappearing beneath. My newfound nemesis, the squash bug.

If you blessedly have yet to encounter this foe, let me describe him: flat, hideous, brownish grayish, looks like a child’s drawing of a beetle from their nightmares, usually loitering around your favorite pumpkin, 2/3 of an inch long — which is small for most things but huge for a nasty little guy. Well, that’s when he’s an adult. As a new hatchling, he’s a tiny, green-bodied, spider-looking creature, and as an older nymph, he’s light gray.

Squash bugs suck the life out of the leaves and stems of squash, pumpkins, and other cucurbits. Small pale specks dot the leaves, which then turn brown and wilt. The plants eventually may die. I had wondered why my poor zucchini was drooping, ’til I saw that first foul fellow. But in midsummer, there’s still a chance. The adults you see in July and into August likely overwintered in yard debris and are busy laying the next generation. If you destroy their eggs and hatchlings before they reach their full power, your plants may survive, and you’ll slash the population attacking through the fall and emerging next year.

Squash bug eggs are shiny bronze in color and laid in clusters, usually on the underside of a young leaf but sometimes on the stems. You can smash them, tear off that part of the leaf, prune the whole leaf, or remove the eggs with sticky tape. The eggs take 5 to 10 days to hatch, so checking leaves every couple of days should catch most of them. This grows more challenging the bigger the plant grows, but for most backyard or balcony gardeners is plausible and worthwhile.

Nymphs and adults can be smushed or drowned in soapy water, though adults are known for evading capture. Neem oil and some other insecticides can harm the nymphs but not adults; handpicking is the most effective control. You can lay out boards, cardboard, or paper at night, which the bugs will gather under for easy removal, drowning, or vacuuming in the morning.

Knowing all this, I became obsessed. With a mighty harpoon (a long stick I found on the ground), I channeled Captain Ahab stalking his White Whale. I overturned every zucchini leaf, rustled every stem, and hunted any remnant of my foe. I squished the hatchlings and scraped off eggs. I stabbed each adult with my harpoon, with unholy squeals of disgust.

As of the first week of August, my zucchini still wilts here and there, but the strong new leaves give me hope. The fruit I’ve harvested has been undamaged aside from a bit of outward scarring. (And it’s delicious. The seeds were an impulse grocery store purchase and I’ll be planting them again: Round Zucchini from Botanical Interests.) So far, I haven’t found any sign of the bugs migrating to my winter squash in another raised bed, though only time will tell. But I will not sit idle while the enemy campaigns. I will continue my egg hunt, a megalomaniacal Easter Bunny lost in the heat of summer. And I will strike the scurrying scoundrel whenever I spot him.

As you’re reading this at the end of August, you may wonder if it’s too late to fight your own infestation. No! Late summer and fall are an important phase of the battle against squash bugs. The egg days may have passed, but you can continue to reduce the older nymphs and adults. The more you kill now, the fewer will survive the winter and restart the cycle next year.

At the end of the growing season, clean up all cucurbit plant remnants in the affected areas, and reduce other plant litter, bark, or other hiding spots as much as you can. Having a sterile, spotless yard is hardly the goal here; many friendly insects and pollinators shelter in the same perennial plant stems, fallen leaves, and mulch as squash bugs might (and organic material is essential to soil health). However, being extra diligent in the localized area can be worthwhile. Removing mulches or tilling under the soil may be justified if you have a severe infestation (even if you generally practice no-till gardening). When you plan next year’s garden, rotate your cucurbits to another part of the yard if possible, or consider skipping them for a year altogether so the squash bugs have no source of food (this is less effective if your live right next to neighbors who grow their own pumpkin patch).

Even with best practices, squash bugs can be wily. Finding every single one in your yard is like hunting for Moby Dick across the seven seas. You’ll probably have to sharpen your harpoon again next spring. Start checking young cucurbit plants for signs of the bugs in May and June when they emerge from their hiding spots, ready to destroy.

I’m grateful to have noticed a squash bug before he and his kin had fully established themselves and invaded all my cucurbits this year. Perhaps next summer will be better, perhaps it will be worse. So it goes in the garden. Tonight, I again will stalk and slay the wretched beasts. But this morning I am chopping up a ripe zucchini, sautéing it with just a bit of salt and butter, and enjoying the fruits of my labor. For now, the hunt can wait.

Lest it be said this column is insect slander, simply because I am factually referring to certain bugs as “hideous” and “a devil,” I should clarify: most bugs are not the embodiment of evil. In fact, 99% of the approximately 1 million known species are neutral or beneficial to humans. It’s only one percent of insects that qualify as pests, and only a small percentage of those do serious damage.

Many, many insects will cause small spots or holes in the leaves of your plants, and that’s perfectly fine. The caterpillars and larvae of friends such as butterflies and lady beetles eat plant material, without harming the plant. Not every aesthetic issue is a problem that needs fixed. Not every insect egg is an enemy laying in wait. In fact, most are not.

When you see eggs you’re unfamiliar with, research before reacting! You can post a photo in a local gardening forum, send a photo to the OSU Ask a Master Gardener page, email a photo to the WSU Answer Clinic, or just google things like “round white insect egg in rows of 6 on back of legume leaf in May PNW USA” until you go madder than a landlocked Captain Ahab. I also have found bugguide.net extremely helpful; it’s hosted by the entomology geeks at Iowa State University.

Over time, the best way to recognize bugs and their eggs, be they friend or foe, is being present in your garden and observing insect activity through the seasons. When I started gardening, I rarely visited my little veggie patch other than to water, so pests often caught me off guard. I only noticed them when they reached peak infestation. By then, it seemed hopeless to fight the pests (and probably was). It’s much easier to address the problem and salvage your crop if you catch it early.

But it’s also rewarding to see your plants fostering thriving ecosystems. I love to watch bountiful bees, flies, moths, dragonflies, and so many others growing, pollinating, just bugging around. I’ve seen more lady beetle larvae this year than ever before, especially on my yarrow. It’s a delight to watch them grow. Uh oh, maybe I’m becoming an entomology geek too…