Powdery Mildew

Natural History

Powdery mildew is caused by several genera of fungi in the Ascomycetes. Powdery mildew can affect a very wide range of hosts, and is usually observed most frequently later in the summer, following humid weather conditions.

The disease is given its name from the presence of the white fungal growth on the leaf surfaces, which appears like white powder. There are several methods for controlling powdery mildew, including preventative fungicide applications, planting resistant species or cultivars, or increasing air movement and eliminating conditions that favor the disease.