RIP squash plants.
Healthy Squash Plant
Over the past few days most of my squash and zucchini plants have wilted and died from squash vine borer. The two plants left have the telltale signs of frass protruding from small holes at the base of the vine. I knew it was inevitable; I’ve been gardening for years and they always manage to get to my plants sooner or later. I fried up my last dozen flowers today and savored every bite of them.
The squash vine borer is actually a moth that lays its eggs on the leaf stalks. The moths emerge from the ground about the same time the vines begin to run. When the eggs hatch, the larvae enter the stems and feed for 4 to 6 weeks. When they are fully grown they leave the stems to burrow into the ground to pupate until next spring. Then they start the cycle over again and emerge as moths and ruin another one of my squash crops.
I have tried everything to stop them. Nothing works. Row covers, wrapping the stems in foil, cutting the stem and removing the bug. Pesticides were not an option for me. The recommended pesticide for this bug is Sevin, which is extremely toxic to bees and other beneficial insects. I have a hive of bumble bees about 3 feet from the vines. And besides, once the larvae are inside the stem, pesticides do not work.
So next year I am going to try and outsmart them. I’m going to plant 3 or 4 successive crops of squash 14 days apart. When I see the signs that a plant is infected (the small holes at the base of the vine), I’ll pull the plant from the ground and send it off with the landscape waste (not to the compost pile) before the larvae mature. This way they will not get into the ground only to return next year. The plant was going to die anyway, I’m just pulling it a little early. And by planting successive crops I’ll still have zucchini and squash.
I’m hoping if I do this for a year or two I won’t have any more borers in the ground. It’s worth a try, nothing else worked.
I like your creativity in not using pesticides. The easy answer would be just destroy everything to get to it. However, reading your story it seems you have to actually come up with an answer and while your plants suffer a little longer when you do finally get rid of them the natural way there will be a sense of accomplishment.
you forgot an important element: do NOT plant zucchini in the same spot next year- MOVE IT to avoid the same problem with the larvae living there. I just hit them with Sevin in June when they start growing well, and rotate locations any year I have borer problems.
Rotating crops is an option if one has the space. I only have two garden beds that are fairly close together. The bug followed me to the new plot.
Sevin will work to kill the bug along with all beneficial insects and pollinators. It’s a toxic chemical so I choose not to use it.
This year only one of my plants got the bug which I removed from the stem. The plant healed and all three are still producing fruit and flowers. It took four seasons but I am now relatively bug free.