Squash Fruit Rot on Trellised Plants: Choanephora or Heat

An experienced organic gardener sees sudden, total rot of squash fruit (all 10 varieties) at all stages—babies to 30-lb giants. Plants healthy, trellised, drip-irrigated, bee-pollinated. Powdery mildew controlled with copper.

Possible Causes

• Choanephora fruit rot: Fungus produces "whisker" growths on mushy fruit. Managed by canopy thinning for air flow; sprays impractical due to rapid fruit set.
• Extreme heat: Disrupts fruit development and promotes rot.

Action

Thin vines aggressively to improve air circulation. Remove all rotted fruit immediately. If heat is the driver, provide afternoon shade cloth. No spray can keep up with daily new fruit.