Insect
Squash Vine Borer
White, fat caterpillars up to 2.5 cm long found inside squash stems; the adult is a wasp-mimicking moth with an orange and black abdomen.
Symptoms to Look For
- Sudden wilting of one or more vines even with adequate water
- Sawdust-like frass at the base of wilting stems
- Entry holes and tunnels visible when stems are cut lengthwise
Affected Plants
SquashCourgettePumpkinMarrow
Organic Solutions
Row covers
Protect plants with fine mesh row covers from transplanting until flowers open, removing for pollination, to exclude egg-laying adults.
Manual removal
Slit infested stems lengthwise, remove larvae by hand, and bury the stem segment under moist soil to encourage rooting above the damage.
Bacillus thuringiensis injection
Inject Bt solution into the stem with a syringe at entry holes when larvae are young and still near the surface.
Prevention
- Delay planting squash until after the first adult moth flight in early summer
- Wrap the lower 30 cm of stems in foil to deter egg-laying near the crown
- Check stems weekly from late June for orange oval eggs and crush them before hatch
Garden, by Willowbottom recommends only organic, wildlife-friendly solutions. No synthetic pesticides, no harmful chemicals - ever.