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Dear Friend and Gardener

Squash Borer Attack

Squash borer and entry

Squash borer entry and damage

Last Sunday I went on an education edible garden tour and learned about the Squash Borer. In the first garden we visited we all noticed a yellowing and flopping squash plant. Was it lack of watering? No! We were seeing the fatal damage  caused by a squash borer.

Though I grew squash in Heath for many years I never had squash borers  so  this was quite an education for me. Espececially since when we got home and looked at the summer squash plants I had put in because I thought all that squash foliage would cover the ground and keep down weeds while other plants grew larger. A couple of my plants  also had slightly yellow drooping leaves and evidence of squash borer entry.

Squash borer larva

Squash borer larva

The fingertip in the photo is just to give a sense of scale.  I immediately went around the garden and found  several more plants showing borer damage. A friend told me all I had to do was slit the affected stem with a sharp knife and that would kill  the borer. I did some slitting but I also did some online research. I don’t think the slitting will do any good.

The adult vine borer is a moth that will lay its tiny eggs at the base of a stalk. They are not really visible and it is only after they have hatched and begun their entry into the stalk, leaving the evidence of their ‘frass’ (the proper work for borer excrement) at the entry point. You can try to slit the stem and pull out the larva which will grow to an inch long, but there does not seem to be agreement that this will lead to a squash harvest.  And to make things worse, since  I have borers now, I probably also have pupating borers in my soil that will hatch next spring!

If I wanted to plant squash next year, not likely, I could choose a different spot and keep the squash plants covered with a floating row cover. However,  the consensus is that prevention is the best answer. Weekly applications of insecticidal soap have been found effective. Also Btk, Bacillus thuringiensis kurstaki, an organic compound found in t he soil can be used regularly. When larva eat this they die.  You can spray with Btk weekly or wipe down  the stems with Btk or insecticidal soap weekly.

I had visions of tons of squash I could bring to the Center for Self Reliance, but that does not seem likely. However,  I’ll be ready if I plant squash next year. Right now that is a big IF.

4 comments to Squash Borer Attack

  • Helen Opie

    Thanks for the heads-up on this. I haven’t seen any for a long time so had forgotten about them. Last year I had my first plague os squash beetles, and also neglected to prepare their hills by planting a ring of radish seeds per Ruth Stout. Most of this year’s squash sites got radishes, though I think small softshelled snail ate many seeds as they pit up their first bit of green.

    Anyhow, nary a squash beetle so far. We had a much warmer start to the season, and until a fee eeeks ago, more that enough rain. I shall look for squash borers, since things seem awfully good out there. Will cut them out and the mound earth over the stem so it can root on both sides and hope they can carry on growing and fruiting. Hope others report on their experiences so we can learn.

    I note the local vegetable farms seem to grow almosr everything under row covers. Maybe I shall follow suit, but what to with the 2 volunteer sunflowers, one in cabbage bed, and one in mixed brassicas & eggplant?

  • I am wondering now if that was my problem a few years ago.

  • Pat

    Denise – I’m glad to think you haven’t had that problem since then.

  • Pat

    Helen – Thanks for the information about planting radish seeds around squash hills. I had never heard of this. And also thank you for reminding me that it can be possible to mound soil over the afflicted squash stem to take root and help the plant recover after pulling out the borers. I will say pulling out the borers is not easy, especially if you don’t catch the problem right at the beginning. Not everything can grow under row covers, but they certainly are a useful strategy.

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