Garden Minute - Powdery Mildew

June 1, 2015

This is Jason Lamb with your Gardening Minute.

Powdery mildews are some of the most common diseases worldwide. Almost all plants can be affected by powdery mildew. In New Mexico, powdery mildew is common on roses, euonymus, crape myrtle, lilac, and turf grass as well as many other species.

All powdery mildew fungi produce a white, powdery growth on the surface of affected plant parts. Individual spots may enlarge until the entire leaf, stem or flower is covered with white powder. Any above ground plant part, including fruit are susceptible to infection. Affected parts may be dwarfed, distorted, and curled.

Powdery mildew fungi overwinter on fallen leaves or spores in or on infected plants. In spring, new shoots become infected from old spores. In general, powdery mildew fungi favors high humidity 40-70% in the plant canopy and warm temperatures 60-80ºF.

Growers can use cultural practices to reduce the occurrence of Powdrey Mildew by pruning out infected plant parts, removing fallen leaves, increase air flow by thinning out plants. Contact and systemic fungicides are also available for most plants. However proper timing of applications and thorough coverage are important. 

If you would like more information on treating powdery Mildew please contact the Extension office at 461-0562. This has been your Gardening Minute with Jason Lamb your Quay County Ag. Extension Agent. Where are programs are open to everyone.

(reference NMSU O & T Powdery Mildew)