Controlling Squash Borer

(Editors note: I have updated information in a new article on this subject. You can see it at Controlling Squash Borer, Part II.)

FOR THE LAST TWO YEARS, squash borer (aka squash vine borer) has ruined my zucchini and pumpkin, and I suspect that it ended my cucumber prematurely, too.  It’s a shame because zucchini is one of the vegetables that my kids will eat without me having to sit on them first.

Squash borer is the larva of the moth shown in the photo below. The moth has a wing span of about one inch.  It lays reddish-brown eggs on the host plant. When an egg hatches, a one-inch, white lava with a brown head emerges. The larva bores its way into the stem of the squash plant, typically in the first inch or two above the ground, leaving a saw dust like material called frass. The plant wilts and then dies.

After two years of trying to grow pumpkin and zucchini unsuccessfully, I was almost to the point where I was ready to give up and not grow any cucurbits for the next few years to see if I could eliminate the pest.  It was particularly discouraging because most people think of zucchini as being easy to grow.

My three-part plan for controlling squash vine borer

Squash Borer Moth

This is my three-step strategy for preventing squash borer.

After researching how to control squash vine borer, I’ve decided to attack the problem with a three-part plan. Here it is:

1. Start plants late. I plan to transplant zucchini and cucumber seedlings during the first week of July, hoping that the squash borer moth will have already attempted to lay its eggs and passed on. In areas with a cold winter, there is only one generation of squash borer.  So with any luck, I will have missed the onslaught. As heat-loving plants, July should be good for zucchini and cucumber, as long as I can keep them watered. I’d expect to get fruit during the second week of August.

2. Plant second crop one week later. In case the first crop gets infected, I’m going to wait a week and plant a second crop (succession planting). If the first crop seems to show signs of being infected, I’m going to immediately take it out so the second crop doesn’t get infected from the first.

3. Protect vines with tin foil. When I first plant the seedlings, I’m going to wrap the stems, starting just under the soil, with tin foil. As the plants grow the tin foil will act as a barrier and prevent moths from laying eggs on the vines.

The video below from The Urban Homesteader shows exactly how I’m going to apply the foil to protect the zucchini and cucumber.

Other organic methods of protecting the plants include floating row covers to stop the moths from laying eggs on the host plant, wrapping stems in toilet paper rolls, putting panty hose around the vines and applying insecticidal soap to destroy eggs. I’m hoping that I won’t need to use any of these additional methods.

If you have an organic method that prevents squash vine borer from eating your cucurbits alive, let us know in the comment section below.

Related articles that might interest you:

1. Do You Really Need to Buy Beneficial Insects?
2. Growing Organic Apple Trees, Part II
3. Wildflowers for Beneficial Insects

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15 Responses to “Controlling Squash Borer”

  1. June 25, 2011 at 3:20 pm #

    I planted an acorn squash in a very large container this year. I have had it covered with row cover fabric ever since it was planted, have hand pollinated 3 squash so far as the female flowers emerge. Will uncover come mid-july when squash moths should have already laid eggs and gone, though I did buy some Seven to continue to spray on the vines just encase some Moths are still around afterward. I’m hoping this will avoid ANY dealings with squash borers.

    • June 25, 2011 at 4:53 pm #

      I hopy your strategy works, but I will not endorse use of the insecticide Sevin. At best it will kill both good bugs and bad bugs. At worse it is a toxic insecticide that could be consumed along with your acorn squarsh.

  2. Margo
    July 26, 2011 at 2:39 pm #

    I tried the toilet paper/ paper towel roll technique this year, and it did not work. Other suggestions I have not tried yet are wrapping the stems in tin foil or with nylon stockings.

    If I ever try the paper towel idea again, I will also put a long length of cupped tin foil inside the towel ring and as the plant grows, pull out the length to cover the base and main stem of the plant.

    My squashes grew out of the polyfiber covering this year, and they STILL got borers.

    I wonder if any of your readers has tried injecting BT by syringe into the stem(s) of the squash plant.

    • July 26, 2011 at 3:41 pm #

      Sorry to hear that toilet paper towel rolls didn’t do the trick. My zucchini is still doing OK. I uses rolls but also planted very late. Since I live in the North where borer is supposed to have only one reproductive cycle, I’m hoping I’m going to be OK. Time will tell. I think I’m about three weeks from zucchini. We’ll see if it works. Let’s see if anyone has tried BT. I haven’t.

  3. August 5, 2012 at 11:34 am #

    Those squash vine borers are the worst. I planted punkins this year and it is my first time dealing with them. I use Neem now but next year I’m going to use Neem and BT injections also I’m going to plant some dummy crops. Check out my homemade seaweed fertilizing mulch formula video.

    • August 5, 2012 at 1:40 pm #

      Joseph — Good luck with your squash borer treatment. I hope it works out for you.

      Funny you should bring up seaweed and bone meal. I’m currently writing an article involving seaweed and bone meal. Be careful with bone meal. There are some experts that believe you can contract mad cow disease from it.

  4. October 5, 2012 at 5:26 pm #

    I had some very scummy zucchini stems thanks to the borers in mid-July this year. I made haste and using a large, sharp T-pin I went all along the wilted portion, from all angles, and up the good portion of stem about 2-3 inches (I was angry!) This proved to be very effective and I’ve had a bumper crop – alas, it might frost tonight, I’m gonna cover them. Last year I did not know about the little devils and simply ripped everything out. Like you, I plan to plant later next year to hopefully avoid the egg laying season.

    • October 6, 2012 at 6:21 pm #

      I’ll keep my fingers crossed and hope that it doesn’t get too cold so that you can eat all those zucchini. Let us know how it turns out.

  5. Valerie Meineke
    June 10, 2015 at 7:25 pm #

    For the last four years I’ve been covering the base of the stem (below the first leaves) with aluminum foil when the plants reach 2-3″ in height. It’s worked perfectly. No need to delay planting or resort to pesticides.

    • June 11, 2015 at 8:43 am #

      Valerie — I think this is an excellent method for protecting squash. Thanks for sharing with us.


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