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