Presumably this is some sort of covering left behind by the larvae.Presumably this is some sort of covering left behind by the larvae.
A cucumber beetle decides to get in on the destructionA cucumber beetle decides to get in on the destruction
YuckYuck
Pretty amazing that the leaf stems are hollow.Pretty amazing that the leaf stems are hollow.
I started pulling the zucchini up and the stem just broke into pieces.I started pulling the zucchini up and the stem just broke into pieces.
Extensive squash vine borer damageExtensive squash vine borer damage
7/22. The final end for the zucchini.7/22. The final end for the zucchini.
7/10. Still hanging on.7/10. Still hanging on.
First squash vine borer damage noticed on 7/8.First squash vine borer damage noticed on 7/8.
  • Presumably this is some sort of covering left behind by the larvae.
  • A cucumber beetle decides to get in on the destruction
  • Yuck
  • Pretty amazing that the leaf stems are hollow.
  • I started pulling the zucchini up and the stem just broke into pieces.
  • Extensive squash vine borer damage
  • 7/22. The final end for the zucchini.
  • 7/10. Still hanging on.
  • First squash vine borer damage noticed on 7/8.

This year we are experiencing a lot of firsts. This is the first year we have grown most of the crops that we are growing: garlic, corn, winter squash, summer squash, potatoes, melons. Growing a plant for the first time means learning what it looks like as it grows, and also learning what pests affect it.

We learned relatively quickly about squash vine borers. A few weeks ago, just a few minutes before the reporter from the Missourian was coming over, I noticed the zucchini was wilting. The soil was moist, so I couldn’t figure out why it seemed to be struggling. I quickly watered it and seemed to recover somewhat, so I didn’t think much of it.

A few days later I noticed that the stem seemed to be chewed up. Instead of looking as if it had been damaged from the outside, it looked like it had been eaten from the inside out. And so it had.

Our zucchini was being eaten by squash vine borer larvae.  The squash vine borer is a moth which lays eggs on squash plants. The resulting larvae then burrow their way into the stem of the plant, and live there happily eating the inside of the stem until the plant eventually dies. As did our poor zucchini. Curse you, squash vine borer!

We got one nice zucchini off the plant (which had its moment of fame in the Missourian story, and was quickly cooked and eaten). One lowly zucchini from what should have been a prolific plant. What a bummer.

The good news is there are a few things you can do to avoid damage from squash vine borers:

  • Plant vine crops that are usually not attacked by squash vine borers, such as butternut squash, cucumbers, melons, and watermelons. (We have all of these plants except cucumbers and none have been affected.)
  • Plant a second planting of summer squash in early July to mature after adult borers have finished laying eggs.
  • Place floating row covers over your vine crops when they start to vine, and remove the row covers when the crop starts flowering.
  • As soon as wilting is noticed, use a sharp knife to cut a slit in the affected stem. Slice carefully up the vine until you locate the borer (or borers). Once you have killed any borers with the tip of the knife, mound moist soil over the cut area and keep this spot well watered.  New roots may grow along the cut stem, allowing the plant to survive.

Now that I know what the damage looks like, I plan to do a better job next year of protecting the plants. Unfortunately a zucchini plant was lost in the name of gaining greater experience with urban homesteading. Squash vine borer – 1, Annette – 0.

You just watch out next year, squash vine borer!

4 Responses to “Squash vine borer damage on zucchini”

  1. What Pigs Don't Know
    26 July 2010 at 12:11 pm #

    This exact same thing to us. I had three large beautiful plants all starting to flower and one morning I came out the the best one was basically decimated. Twenty four hours later, they hit the next largest; and the next morning, the smallest of the three. I wanted to cry! I even knew what was happening but was helpless to stop it – oddly enough I never saw a single bug or larvae, just the aftermath of their destruction. I think the best bet is the floating row cover & planting successions of them every few weeks so at some point the moons will align and a few plants will actually make it! -Carrie

  2. Sondra
    1 July 2013 at 5:00 pm #

    Thanks for this post. Found them for the first time this week. Lost 3 big plants – and just noticed a really healthy one won’t be for long. But that’s a great idea to try and kill the worm. Will give it a shot on the last plant.

  3. Julia
    24 July 2013 at 10:00 pm #

    Are you sure this doesn’t happen to cucumber? I had in one day an entire vine of my cucumber plants just start to wilt and die. I thought maybe the vine had broken in the heavy rain (that happened to one of my tomato plants) but it looked completely intact. I have cut it off just below where the first leaves started to die and I hope that it will grow back. My summer squash is having some sort of similar problem, but it is such a mess I can’t even make out what vine is affected and which isn’t – it is a bird droppings in our compost pile planting or something because I didn’t put it there….


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  1. […] I pulled up my zucchini plant which succumbed to squash vine borer damage, I later noticed it had two pristine examples of baby zucchini on it. How sad. […]