Organic Pest Control for Vine Borers

Squash vine borers also attack pumpkins, zucchini and watermelon.

Although usually referred to as the squash vine borer (Melittia cucurbitae), this pest also commonly infests zucchini, pumpkin, cucumber, muskmelon and watermelon vines. The winter squash variety "Hubbard" is particularly susceptible, whereas the butternut squash is resistant.

Signs of Infestation

Vine borer larvae, which are white, brown-headed worms approximately 1 inch long, enter the plant stem and burrow toward the base of the plant. As they bore, the larvae destroy the vine's vascular tissue, which causes the runner or the entire plant to wilt and die. Besides wilting, signs of infestation include a sticky sawdustlike substance called frass near the plant base and yellow-brown excrement pushed out through holes on the stem.

Organic Controls

Traditional insecticides are ineffective against vine borers once they are inside the vine. However, row covers offer plants protection, and home gardeners can deworm affected vines. Slit the vine lengthwise near damaged areas, extricate the worm and cover the stem with earth. The Missouri Botanical Garden reports Bacillus thuringiensis can be injected into vines to kill borers, and researchers at New Alchemy Institute had similar success injecting nematodes.

Prevention/Solution

Preventing vine borer infestations is essential to successful harvests. Destroy residual vines immediately after harvest and rotate crops year to year.

References

• National Sustainable Agriculture Information Service: Squash Bug and Squash Vine Borer: Organic Controls
• University of Kentucky College of Agriculture: Squash Vine Borer and Squash Bug
• Resource Guide for Organic Insect and Disease Management: Crop Managment Practices -- Cucurbit Crops
• New Alchemy Quarterly: Nematodes, Zucchini and Vine Borers
• Mother Earth News: Organic Remedies for Garden Pests
• Missouri Botanical Garden: Squash Vine Borer