Downy mildew on impatiens

The disease downy mildew on impatiens is caused by Plasmopara obducens. Like Pythium and Phytophthora, Plasmopara obducens is an oomycete, or water mold. The spores have a tail which allows them to swim through water. Spread of infection can progress quickly in wet, moist conditions.

There were reports of downy mildew on impatiens in landscapes in several regions of the country in 2011, including several states in the northeastern US, midwest, and southern coastal California. Greenhouse growers and landscapers in cool, wet areas of the country, are encouraged to increase their knowledge and monitoring for this disease.

Resources:

Creswell, Tom. "Stealthy Disease of Impatiens May Go Unnoticed" Purdue Plant & Pest Diagnostic Laboratory. 26 Sept. 2011. Web. 9 Feb. 2012.

Hausbeck, Mary. "Downy mildew causing problems on impatiens in the landscape." Michigan State University Extension News. 12 Oct. 2011. Web. 12 Oct, 2011

Schubert, Tim. "Downy mildew of Impatiens walleriana caused by Plasmopara obducens". Pest Alert. Florida Department of Agriculture and Consumer Services. 9 Feb. 2012. Web. 10 Feb. 2012.

Warfield, Colleen. "Downy mildew of impatiens." GrowerTalks. Vol. 75. no. 10. 9 Feb. 2012. Web. 9 Feb. 2012.

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Robin Rosetta