Troubleshooting
Cushaw Squash problems — and how to fix them
Cushaw Squash (Cucurbita argyrosperma) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Powdery mildew
Even heat-tolerant cushaw can develop powdery mildew on mature leaves in late summer. Symptoms are white powdery coatings on leaf surfaces. Maintain plant spacing of 4–5 ft, water at the base, and apply a preventive sulfur spray if conditions are humid.
Squash bugs
Bronze egg clusters appear on leaf undersides from early summer; nymphs and adults suck sap causing wilting and bronzing. Hand-pick egg masses and adults daily. Cushaw is less susceptible than C. pepo varieties but not immune — monitor regularly and use kaolin clay as a deterrent.
Poor pollination in high heat
Flower abortion increases when daytime temperatures exceed 35°C (95°F) consistently, as pollen viability drops. Hand-pollinate early morning using male flowers. Growing companion flowers to attract bees helps maintain reliable pollination during heat events.
Prevent cushaw squash problems before they start
Most cushaw squash issues are care-mismatch, not bad luck. Dial in the basics:
Looking for cushaw squash in general rather than its problems? Read the full cushaw squash care guide — light, water, soil and feeding.
Cushaw Squash problems — FAQ
Why is my cushaw squash powdery mildew?
Even heat-tolerant cushaw can develop powdery mildew on mature leaves in late summer. Symptoms are white powdery coatings on leaf surfaces. Maintain plant spacing of 4–5 ft, water at the base, and apply a preventive sulfur spray if conditions are humid.
Why is my cushaw squash squash bugs?
Bronze egg clusters appear on leaf undersides from early summer; nymphs and adults suck sap causing wilting and bronzing. Hand-pick egg masses and adults daily. Cushaw is less susceptible than C. pepo varieties but not immune — monitor regularly and use kaolin clay as a deterrent.
Why is my cushaw squash poor pollination in high heat?
Flower abortion increases when daytime temperatures exceed 35°C (95°F) consistently, as pollen viability drops. Hand-pollinate early morning using male flowers. Growing companion flowers to attract bees helps maintain reliable pollination during heat events.