Mint for Squash Borers?
Answered by: Conrad Richter
Question from: N. Keber
Posted on: January 20, 2002

I had read in an old issue of Organic Garden Magazine that a few readers had suggested planting mint in their squash beds to deter squash borers. Do you know anything about this idea? Would it work just to set pots of mint throughout the bed rather than truly plant the mint since it is so invasive? I wonder is it just the fragrance of the mint, or something that is released into the soil by actually planting the mint. Thanks for any information you have on this issue.

We have not heard of this effect of mint on squash borers before. Louise Riotte in her book, "Secrets of Companion Planting for Successful Gardening" (Garden Way Publishing, 1975) does not mention it either. Helen and John Philbrick, in their book, "The Bug Book: Harmless Insect Controls" (Storey Communications, 1974) recommend spinkling camphor or black pepper around the roots of the growing squash plants to repel the moth that lays the eggs of the borer. They stress that the camphor has to be the real thing, not a chemical substitute such as naphthalene.

Taylor’s "Organic Pest & Disease Control" (available from Richters) recommends covering squash plants with floating row covers from planting until flowering to protect plants from the egg-laying moths.

We too are skeptical of how mint would work interplanted with squash because of the invasive nature of mint. But then again squash is itself quite a vigourous grower and may be able to withstand mint’s agressions. Mint takes two seasons to really fill in and crowd out other plants so it might just work with newly plant mint.

Does it make a difference if the mint is planted in the garden or kept in containers? We don’t know, but if mint works all our guess is that it does so by emitting repellent vapours to the air and not by exuding chemicals in the soil. The vapours would presumably repel the moths that lay eggs. Would placing potted mints here and there throughout the squash patch work? That depends on how much of mint’s oils need to be present to repel the moths. Obviously, the more mint, the more fragrance, so maybe it is better to interplant mint in the ground.

There are of course many varieties of mint. Probably peppermint is the best choice because it has the strongest menthol aroma.

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