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my recent adventure with squash bugs

ADD THEM TO THE LIST of creatures I’ve had to stalk in my rounds each day through the garden, things I’ve been squishing or drowning in the hopes of having a harvest of favorite crops myself–and not letting insect pests eat it all first. One enemy on the scene that I seem to now have under control: the squash bug (who looks a lot like the hated stink bug, but isn’t).

The most common “squash bug” is Anasa tristis. I even have some that overwinter in my house (along with Asian lady beetles and stink bugs–whee!). I love that its Latin species name, tristis, means sad–which is what it was making me a couple of weeks ago when I was picking these guys off regularly. (A side note: I wondered if I actually had the helmeted squash bug, Euthochtha galeator; an almost-lookaline, but caught some and really examined closely.) Anasa prefers lay its eggs on the foliage of squash and pumpkins (but in a pinch will eat foliage of other cucurbits); some varieties are more resistant than others to its trouble-making, one of those being ‘Butternut.’

Though for long it was not thought to be a spreader of bacterial disease—the way the cucumber beetle is—in recent years Anasa tristis has in fact been identified as a vector of yellow vine decline (a pdf on that, from the University of Kentucky, is here).

Even without that more serious potential outcome, an unchecked infestation of squash bugs will pierce and suck on leaves, causing damage and wilt of a non-bacterial kind—and eventually leaf necrosis—and will even damage the skins of fruits later in the season. Watch carefully in spring (later May and through June here, especially)—the first sign will be small yellowish or brown dots (above), or if things have already progressed, some wilting.

The key to managing squash bugs is to not let them build up—meaning strict cleanup in the fall to reduce overwintering of unmated adults, and prompt attention in the spring, when young plants are especially susceptible and insect populations are rising. Check the undersides of leaves daily for egg masses or nymphs (recently hatched bugs); you can see what each stage—egg, various nymphs, adult—looks like on the University of Minnesota Extension site here. Either I got all the overwintered adults just as they awoke (before they reproduced) or there weren’t many, because a week of vigilance last month seems to have rid me of any serious troubles, and my plants are now fine.

I was able to catch adults in the early part of the day near the base of the plants or under leaves, and you can lure them to hide under boards or shingles at night much like you would slugs by day, but they move much faster once fully active. “Empty” your traps first thing daily.

Growing resistant varieties is recommended. Besides ‘Butternut,’ the University of Arkansas suggests ‘Royal Acorn,’ ‘Sweet Cheese,’ ‘Green-striped Cushaw,’ ‘Pink Banana,’ and ‘Black Zucchini.’

And then there is the tactic of succession sowing—one of the best defenses a gardener has against wholesale loss of any crop, really. Plan to have multiple sowings coming along—not all your cucurbits at the same stage of development at once, potentially coinciding with the worst invasion. When I saw the first squash bugs, I made a note to plant another hill of squash just in case I failed to thwart the pests on the original plants.

Even if I hadn’t seen those squash bugs, a late sowing would be a good idea–a summer planting of a bush variety of squash or two. After all, who knows what pest will move in next–or perhaps in a hot, dry season like this the early plants will simply poop out (like the gardener feels like doing about now).

expert help with squash and other cucurbits

 

  1. Urgh. I’m thankful that I only had squash bugs one year, in a bed full of kabocha squash. I spent an entire afternoon turning over leaves to find the egg clusters, then cutting off the whole leaves and burning them – must have burned half the leaves, but I got rid of the bugs, spared the crop, and haven’t seen squash bugs again (fingers crossed). That was the same year I had such a terrible cucumber beetle infestation that I took to vacuuming them up with the ShopVac each afternoon (when they seemed to be most active). Spraying with nematodes to combat the cutworms seems to have cut down the cuke beetle population, too (another cross of the fingers).

  2. Dd says:

    Best post ever. I have been plagued by these guys for years and it was really bad this year. Had to pull up plants. Very few squash for me this year, but I feel armed w better strategies for next year. I was afraid my tomatoes had blight, but according to y r info, I guess I’m ok. Thanks tons!

  3. Carol says:

    I’ve been so frustrated by squash bugs in recent years – plants take off great, set fruit, then the plant dies before fruit gets big. Finally decided to skip a year last year. Hoping I can get mature plants this year. Will try the row covers to keep visitors off.

    1. margaret says:

      Hi, Jean. Yes, effective indeed, but because it “kills any bug” I don’t use it; I don’t want to use pesticides that are indiscriminate, whether they derive from natural materials or not. Bonide is natural, but not approved for organic use (not OMRI certified). I find that good sanitation, especially in spring and fall, and vigilant squishing at egg-laying time keeps things under control without any risk to any insects I might not wish to harm. Fussy, I know. :)

  4. Mary JO says:

    Will Seven Dust 5% help rid my garden of squash bugs? They have killed all of my squash plants as well as my zucchini plants….

    MJ

    1. margaret says:

      Hi, Mary Jo. I cannot imagine any reason to purchase or use (or expose my garden or myself to) Sevin, which indiscriminately kills beneficial insects, too, and is illegal in numerous countries.

  5. Belinda says:

    I planted a garden for the first time in about 15 years, I am working on good soil, I mixed in cotton burr compost and mulched with about 6 inches of straw. I am loving that but found I planted WAY TOO MUCH! Next planting, I will scale back by half. I have gotten frustrated when my tomatoes were slow to fruit and they are just now starting to pink up. My yellow squash took off like crazy and I have so much but now its become infested with the squash bugs and I have given up, they are not producing but a couple per week now and I was wondering, can I dig them up and toss them away? It doesn’t seem like a good idea to leave them there to compost. I am leaving the state for over a week in a couple of days and have now just thrown my hands up and will see what I have when I return. On a big plus side, I have eggplant, bell peppers and hot banana peppers! And oh my gosh, a shop vac?? I never would have thought!!

    1. margaret says:

      Hi, Belinda. Overdoing it is the most common mistake we all make when we are new to gardening or getting started again — enthusiasm outweighs our reason! :) With the infested squash, do remove the debris to another location and clean up the area well.

  6. shiner says:

    The bug which takes its toll on my squash and cucumbers is spotted with black dots on a yellow backround. It decimates the leaves, and I pick them off and squish a daily basis.

    I always thought they were squash beetles… Any idea what these are?

  7. Lynda says:

    I have just finished pulling the last of my squash and zucchini plants due to squash bugs. I did manage to get some squash and zucchini before the invading army landed but I lost the battle with them. My question is what can I plant now for in that bed for fall harvest that the bugs will not invade like my squash and zucchini. Or should I just leave it alone and plant somewhere else?

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