Squash vine borers love zucchini. The adults emerge from their winter hideout in the soil sometime in late June to early July, and one of their first tasks is to lay their eggs at the base of squash plants. When the eggs hatch, the larvae burrow into the stems of the plants and start to feed. This cuts off the flow of water through the stems and can quickly kill your beautiful zucchini plants.
To avoid squash vine borers you could outsmart them by not planting your zucchini until mid-July. If there are no zucchini plants in your garden, there is no reason for the vine borer moth to stop by and lay her eggs. Plus, if you do have squash vine borers in your soil, delaying planting for one year can break the cycle of them infesting your plants. The larvae will wake up and not have anywhere to feed, rather than feeding on your plants and eventually reproducing themselves.
But if you really want early zucchini, there is another way to foil this pest, which requires using foil. You can wrap the base of each stem with a small piece of aluminum foil. You only need to cover about 2 to 4 inches of the stem where it comes out of the ground. If you wrap the foil securely, the larvae shouldn’t be able to bore through it.