October 2021

With Halloween coming up, there are spooky times among us, especially for pumpkin farmers.

Pumpkins are a staple for fall festivities, but they are also a great food and moisture source for microorganisms. Below are three common microbes that contaminate commercial pumpkin farming every season.

Erysiphe cichoracerarum

Erysiphe cichoracerarum is a fungus that affects the leaves of pumpkin plants, causing powdery mildew. The disease is not fatal but does stunt pumpkin growth. Proper planting sites with good sunlight and air circulation inhibit fungal spread. If growth persists, fungicides may be used to manage plant disease.

Xanthomonas campestris

A seed-borne pathogen, Xanthomonas campestris causes bacterial spots on the leaves and surface of pumpkin plants. The bacterial spots range in color from white to brown and form scabby or lifted lesions. For healthy pumpkin growth, rotating crops and using copper-based formulations prevent further disease.

Sclerotium rolfsii

This soilborne fungus causes a harsh disease in pumpkins called southern blight. Southern blight rots fruit and leads to white mycelium growth on the plant’s surface that is in contact with the inoculated soil. Sclerotium rolfsii thrives underground and all contaminated soil must be removed to continue fresh pumpkin growth.

This season may be scary, but your pumpkins do not have to be. Pick your pumpkins with confidence and know the organisms on your jack-o-lantern this Halloween.