Squash vine borers
Squash vine borers are formidable pests—even a couple can destroy an entire plant. Adult moths lay eggs on the vines, usually at the base of the plant, and the hatched larvae burrow into the stem to feed. Sudden wilting of leaves is a telltale sign of infestation. The timing of chemical control is tricky. Pesticides must reach the larvae after they hatch but before they burrow into the vine. Application to the vines at weekly intervals may control the life cycle. In a small garden, organic control may be practical by monitoring plants and hand-picking eggs. In infected plants, look for an entrance hole near the base of the vine marked by a small mound that resembles wet sawdust. Slit the stem with a knife and find and remove any whitish grubs, then mound soil over the wound to promote new root growth. Some gardeners routinely shovel a spadeful of dirt at several leaf nodes along the vine to encourage supplemental root development, which may help the plant survive if the main stem is attacked.