If you’ve ever been enjoying a squash, melon, or cuke harvest only to have the vines suddenly whither and spill something that looks like sawdust (“frass,” in botanical terms), you’ve probably run afoul of the squash vine borer. This creepy little worm is the larva of a small red and gray wasp-like moth, and will happily hollow out the stems of your cucurbits.
They can kill your plants in nothing flat, and the worst part is, you usually can’t see them until it’s too late. If you do notice frass, you can slit the vines lengthwise near the entry holes (the worm hatches out of the soil before climbing up and chowing down) and remove the critters by hand. But you may still lose the plant.
How to Prevent Squash Vine Borers with Aluminum Foil
This is one of those cases, then, when the “pound of cure” approach is more or less useless. The ounce of prevention works much better. Some organic insecticides may control the borers, if you spray often enough, but there’s another solution some gardeners swear by: aluminum foil.
Squares of heavy aluminum foil measuring 15-18 inches on a side, placed shiny side up around the bases of the plants, seem to help keep borers away. Whether the foil acts as a physical obstacle or the reflection does the job remains uncertain.
Want to learn more about squash vine borers?
Here are some helpful resources:
Squash Vine Borer Management in Home Gardens from University of Minnesota Extension
Biology and Management of Squash Vine Borer in Organic Farming Systems from Extension.org
i have tried both foil and dixie cups. borer still gets to plant
Have you heard of ace bandage, wrapped around base of plant but not too tight?
nothing really works very well, only covering till blosuming
Has anyone tried food grade diatomaceous earth around the base of the plant?
I’m located in North Central Texas and battle these little buggers every year. I use it directly on the stems themselves. One year I found after heavily coating the stems with DE, then it rained, that it turns into a paste that sticks to the stems. Wet or dry the SVB won’t eat thru it. I still had the occasional one eat its way down a leaf stem and injected BT; that took care of it. If you have really heavy rains the DE will wash off, so now I mix a paste of it and apply with either my hands or an old paint brush. Hope this works as well for you as it has for me, happy gardening!
This is the first year I’m trying butternut squash. Have tried the aluminum foil with pepper squash with no luck. Last year I tried planting catnip as a deterrent with zucchini and it seems to work. Am trying it again this year with zucchini and butternut squash(2 separate beds). Hope I have luck this year as well!
I have seen some gardeners regularly inject the fat main stalks before the fruiting vines with a BT solution as a preventative measure before ever getting infested with those pesky vine borers. They swear it works!