by Michael Allen Rogers, Entomology major
If you have ever had a garden, or been to the park during a period of high rain, you have more than likely encountered powdery mildew. Powdery mildew has been a known world-wide disease since 1958, caused by the fungi Erysiphe cichoracearum and more commonly today from Podosphaera xanthii. It appears as a white, powdery fungal growth – seen clearly on the leaf surfaces as well as petioles and stems. Not only is this an issue in your backyard garden, but it wreaks havoc in agricultural production on a world-wide scale. The fungus can be prolific and develop very quickly; as few as 3 days. Affecting cucurbits, or the gourd family, powdery mildew strikes when a hot and humid day comes along and there is sufficient darkness (affecting lower leaves or those under some sort of cover/shade).
Powdery mildew can decimate a harvest, leaving improperly ripened fruits or outright killing the plant. Using fungicides may be effective, but preventative measures can help stop it before it starts. When watering your pumpkin, gourd, etc., make sure to not apply water directly to the stem, leaf or fruits. If one applies water directly to the roots from the soil or avoids watering on hot or humid days, powdery mildew can be kept at bay before it begins.
McGrath, Margaret Tuttle. “Vegetable Crops Powdery Mildew of Cucurbits.” Cornell University, Plant Pathology and Plant-Microbe Biology Section, Long Island Horticultural Research and Extension Center. Web. 2017.
This blog post was an assignment for Societal Issues: Pesticides, Alternatives and the Environment (PLNTPTH 4597). The views expressed are those of the author and do not necessarily reflect the views of the class, Department of Plant Pathology or the instructor.