%^&$*! Squash Vine Borer (educational)

Hello, hello!

It’s Donna, the prodigal Master Gardener, returned to share a bit about my recent discoveries regarding the dreaded and devastating squash vine borer.  My apologies for being gone for so long – sometimes life just gets in the way of things…This year my garden is back in full-swing as are, unfortunately, the squash vine borers.

Here’s a squash vine.  Looks pretty healthy, yes?

Look again, see anything funny?  (here’s a hint)

That, my friends, is a squash vine borer egg, about the size of a pinhead.  Here are some more:

I don’t know why I didn’t think of looking for the eggs sooner, but I got the idea from Dead Snails Leave No Trails: Natural Pest Control for Home and Garden. Isn’t that a great name for a book?

Some of you with long memories may recall from past posts of mine that I’m a big fan of manual control of pests (Cabbage worms, Squash bugs).  So naturally the idea of ‘search and destroy’ excited me.  I set out to do just that over the course of a couple of days, and I routinely found the eggs as you see above.  While they are quite small and easy to miss (as you’ll see momentarily), they are easy to pick off (I’m actually collecting them in a small jar, though I really don’t know what for…)  I was very excited, thinking, ‘NOW I’VE GOT YOU ALL!!!!!  I’m cutting you off at the source!  BWAHAHAHAHAHAHAHAHAHA!’  Ahem.

I proceeded to rest on my laurels as I began to enjoy a bumper zucchini crop.  But then, a couple of days ago I started to notice that ever-familiar sawdust-lookin’ stuff called ‘frass’ coming out of some of my vines.  I was in disbelief, how could I have worms?  I was so careful!!!

So, I embarked on ‘Plan B’ of ‘Save my Zucchini’ – search and destroy the worms themselves.  I was so bummed that I had to resort to what I like to call ‘precision surgery’ – carefully inserting a knife into the wounds and ‘coaxing’ out the worm.  Or at least jabbing or slicing it ‘in situ’.

 Hey look, here’s one now:

This is, er, was actually still a fairly small worm.  They can get about twice this size if you don’t catch them first.  And if you don’t catch them soon enough, here’s what can happen:

I regret to say that I’ve lost a couple of my zucchini plants after all, and may lose more.  But through this experience I learned a couple of very important points that I want to share with you, to help you in your own quest to ‘search and destroy’.

First, I always thought that since I saw the frass on the main stem of the plant, that the eggs were deposited on that main stem.  What I’m finding this year is that, as in the first photo above, the eggs are usually laid on a leaf stem (not far from the main stem).  This was a surprise to me, but it made it easier to find and pick off the eggs.  What the worms do, apparently, is make their way down the hollow leaf stem to the main stem.  So when you’re looking for worms, look for damaged leaf stems.   You might see holes or slits in them, with browning around the edge.  If you can find the worm before it gets to the main stem you just headed off a LOT of damage.  Just cut off the stem at the base.

Second, eggs can also be laid on flower stems.  Check this guy out:

 It looked like he was hiding from me, but, alas, he didn’t last long, either.

Third, the book I referred to above indicates that the plant MAY be able to be saved if the damage isn’t too severe.  Mound up soil around the damaged vine, and (according to the book), the stem will begin to grow new roots.  I’m not sure if my vines are too far gone at this point, but I figure it can’t hurt.

Well, I hope you’re faring better with this year’s zucchini crop than I am.  Though I guess I’m doing better than I would have had I not collected a couple dozen squash vine borer eggs.  Still, I’m encouraged with my new-found knowledge because it gives me another tool to (naturally) battle a formidable foe in the future.  After all, one thing I love about vegetable gardening is…there’s always next year.

11 Comments on “%^&$*! Squash Vine Borer (educational)

  1. I haven't had trouble this year with the squash vine borer (yet), but the deer are wiping out my zucchini.


  2. Excellent advice! I kept checking my main stems for eggs, but I never thought to check the leaf or flower stems! I guess that's how they got in because I just pulled 5 or 6 out of my vines this weekend and I share your sentiments: #^%@!! I'm hoping my plants can survive the surgeries, too. I can't believe that these huge, healthy plants can be taken down so quickly by those vile little creatures!! Fingers crossed for our cucurbits!


  3. A technique that comes recommended is that instead of slicing the stem open to find the bore, just use a needle to stab down the stem and stab the little critters.

    My first planting of zucchini is just about finished, but I started a second planting in pots when the first set of plants started to produce female blossoms. The second planting of cukes and squash went in the ground 3 weeks ago under row cover and has just started to bloom. I'll be pulling the row cover off in the next several days. Squash vine bores tend to be gone by the end of July, so the only pests I have to worry about are squash bugs and cucumber beetles


  4. Thanks for this, I was afraid of these nasty little critters and , today, they reared up and presented themselves. Quick, quick, quick, they are! I've buried the stems of the worst affected plants and treated all my squashes with neem oil. Cleaned all the leaves from and back. And though I realize it's likely too late, put in fresh seeds under cloches for some. Especially my spaghetti squash, which I'm afraid at this point, doesn't have a prayer. Fingers crossed something survives!


  5. Thank you sooo much for this post. I'm on my second round of squash, the vine-borer got the first round. This evening I found the little eggs, thanks to your post. Hoping these little squash plants will be vine-borer free!


  6. Ug…my nemesis. They wiped out my zuchs as well and I found one in my fairly young spaghetti squash today. I think next year I am going to put up row covers.


  7. Ug…my nemesis. They wiped out my zuchs as well and I found one in my fairly young spaghetti squash today. I think next year I am going to put up row covers.


  8. Hey, gang!

    So I did a disappearing act…I posted this post and then went out of town without any connection to the internet for a week. I'm just getting back.

    So glad you all got something out of this post, even if my poor babies suffered for it. I lost another plant or two in the last week, but a couple whose stems I buried have survived!

    Good additional tips and insights in the comments – thanks Kent and 100AcreWoods. This is such a hard pest to keep up with!!!


  9. If the plant will sprout roots from buried vine, would it be any use to bury a portion of the vine further down the plant BEFORE they lay eggs. Then there would be established roots in different locations and if one section got wormed it could be cut off and the rest of the plant may be better able to survive. Anyone tried this?


  10. Yes! This works for winter squash and pumpkins that vine along the ground.

    Try digging out the borers but NOT cutting the vines. That way the plant benefits from having new roots plus the compromised vascular system of the infested vines.


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