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ginak08

SVB war is on!

ginak08
11 years ago

Hello all,

I just returned home from vacation last night to find most of my squash and zucchini plants wiped out. Our neighbor, who was taking care of our yard, called to tell us that our yard was being taken over by "hornets" to the point he had a hard time mowing. He said he thought they had a nest in or near a dead squash plant. He said he used about 8 cans of wasp/hornet spray but it did not seem to do anything and it was practically impossible to enter our backyard in the afternoons. Upon coming home and examining the plants and "hornets" I am pretty sure these are adult squash vine borers. Most of my squash and zucchini plants are dead or dying but my watermelon, cucumber, and pumpkin plants have not seemed to be affected *yet*. Is there any way to get rid of the adult svbs? chemical warfare is fine with me. I want my backyard back so the kids can play and I definitely want my cucumbers, watermelons, and pumpkins to stay healthy and happy.

The rest of my garden is coming along just beautifully, by the way. Before we left , we installed a drip irrigation system on a timer. My plants love it, but so do the weeds, so I have much weeding and harvesting as well as unpacking to do. I just want my backyard back.

Any recommendations you have from experience will be much appreciated. Thank you!

Comments (6)

  • scottokla
    11 years ago
    last modified: 9 years ago

    Any description of the hornets. The first thing I think ofthis time of year is cicada-killers.

  • ginak08
    Original Author
    11 years ago
    last modified: 9 years ago

    orange body, black wings and head.

  • Okiedawn OK Zone 7
    11 years ago
    last modified: 9 years ago

    Gina,

    It is great to hear that the rest of the garden is doing so well and that the drip irrigation on a timer is keeping your garden plants happy. I hope your vacation was both fun and relaxing.

    Now, let's address the SVBs, First, you have to laugh with me when I say this, alright? I'm not saying it to be mean, but rather to be completely honest: The war is not on. The war is over and your plants lost. If you have any surviving squash plants, unless they are C. moschata types, their chances of surviving SVBs that already have killed most your plants are somewhere between slim and none.

    With squash vine borers in our climate, the only hope any of us has lies in prevention. Once they hit your plants, there's a very low success rate in combating them.

    I'm going to link information that includes a list of chemicals used on them in case you want to try chemicals. I don't use these chemicals for SVBs myself, so cannot tell you from first-hand experience whether they are effective or not.

    Rather than using chemicals, I rely on Integrated Pest Management. With IPM techniques, I can mostly control them, at least long enough to harvest plenty of summer squash. I also plant seeds of new squash plants, as far away from the existing plants as possible, about every 3 or 4 weeks. That gives me backup plants away from the main planting. Sometimes the SVBs find the main planting and miss the backup planting on the other side of the garden, but sometimes they find the backup plants while they're still young and take them out too. Sometimes I have no SVBs at all, like last year, but that's likely a function of the weather conditions more so than anything I've done.

    The best way to prevent them is to keep your plants covered with a floating row cover like Reemay or Agribon, and to lift the cover only long enough to hand-pollinate the squash yourself. Or, keep them covered until they bloom, and then remove the floating row cover permanently and just take your chances after that.

    Most years I get a really good squash harvest early, and I plant a ton of plants so I can freeze a lot of it. Then, SVBs arrive in July and take out the plants most years, and then, after I've removed the plants and put them in black garbage bags (in case there's lingering SVB larvae in them), I replant for a fall harvest. I do that even if the succession plants escape SVB damage in July, because we often have a second generation that's likely to hit the succession plants.

    Your clean-up of the SVBs does not end when you remove the plants. In the winter, you need to rototill, plow or dig up the entire area where you grew squash and search carefully for cocoons overwintering in the soil. Remove and destroy any you find. Repeat the process several times over the course of the winter. Then, next spring plant the squash in a different part of the garden and put something that is not related to squash in the area where you have had the squash this year. The worst thing you can do is put the squash next year in the exact same place as you had the squash this year.

    Had you been home when they hit, you might have been able to take a sharp paring knife, pocket knife or razor blade and slice into the stem, find the SVB larvae, remove them, kill them, and put the stem back together, packing several inches of soil firmly on top of it to sort of serve as a bandage to cover the open wound. Then if you had kept the plant well-watered, it would have had a chance to survive. However, in our climate, this sort of plant surgery often only gives you a few days or a couple of weeks longer with the plant because, as your neighbor noted, more of those clear-wing moths just keep coming.

    Some people use either Bt 'kurstaki', beneficial nematodes, or spinosad, injected into the squash stems weekly with a syringe, to try to kill the SVB larvae once they make it ino the stems. Some have success with that, some don't. It is easier to use this technique successfully in a more northern climate than ours, where there is only one generation of SVBs. Here, where we have a least two generations, it may not be as successful.

    Another way to get a squash harvest despite the SVBs is to plant C. moschata types. For winter squash, I usually rely upon butternut, Seminole and Tahitian Melon. I've lost both butternut and Tahitian melon to SVBs in some years, but never Seminole. A lot of people plant zuchetta for summer squash because it also is very SVB tolerant.

    Planting a strip of buckwheat alongside your squash may help reduce the SVB population by attracting beneficial insects that attack the SVB larvae. If you plant the buckwheat seeds the same time you either plant your squash seeds in the ground or transplant squash plants into the ground, because buckwheat is a fast grower, it will be up, growing and flowering before the SVBs arrive.

    As far as SVBs attacking melons or cukes, I've never had them attacked by SVBs so I don' consider it much of an issue. Other people may have had theirs attacked by SVBs and may have advice in that area.

    Hope this helps,

    Dawn

    Here is a link that might be useful: SVB Control

  • Okiedawn OK Zone 7
    11 years ago
    last modified: 9 years ago

    Sounds like the moth that lays the eggs from which the SVB larvae hatch. See photo below.

    Dawn

    Here is a link that might be useful: SVB Moth

  • Okiedawn OK Zone 7
    11 years ago
    last modified: 9 years ago

    Gina, This document is full of helpful info. It may be too late to help you much this year since they've already got most of your plants, but it should you give you ideas for drawing up next year's battle plan.

    Dawn

    Here is a link that might be useful: Organic Control of Squash Pests

  • scottokla
    11 years ago
    last modified: 9 years ago

    Thanks for the info (esp the pic Dawn), I'll be on the lookout for those in the future.

    I still can't bring myself to kill tobacco hornworms because of memories of childhood and the cool moths, but I can probably kill these. They still look cool though.

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