Impatiens Downy Mildew Found In Ohio

Impatiens Downy Mildew. Photo courtesy of Ohio State University Extension.

The devastating impatiens downy mildew disease has been found in Ohio for the 2013 growing season, according to a report from The Ohio State University Extension

“In the last seven to ten days there have been several reports of impatiens downy mildew’s appearance in the Midwest; as of this time we have two reports from Ohio,” according to an article on the Ohio State University Extension website written by Francesca Peduto Hand and Nancy Taylor. “The pathogen that causes the disease, Plasmopara obducens, is extremely aggressive on bedding plant impatiens and Ohio’s impatiens producers should be aware of and scouting for this disease.”

The article cites the early symptoms of impatiens downy mildew as a slight curling or mottling of the foliage, which may be subtle. High humidity, however, can result in a heavy coating of white sporulation on the underside of the leaves.

“One grower described white dust floating above the plants when they were disturbed,” the article states.

Researchers at Ohio State are interested in collecting diseased plant samples and will perform tests at no charge. Growers are asked to send samples to: 

C. Wayne Ellett Plant & Pest Diagnostic Clinic
Ohio State University
8995 E. Main St., Bldg. 23
Reynoldsburg, OH 43068
Phone: (614) 292-5006

Pictures of diseased plants and information regarding location and the extent of the problem can also be eMailed to to ppdc@osu.edu.

For more information on symptoms and treatment, visit Greenhouse Grower’s Downy Mildew On Impatiens: Resources And Advice page

Leave a Reply

One comment on “Impatiens Downy Mildew Found In Ohio

  1. John Esser

    Apparently Impatiens Downy Mildew was found in a Wisconsin greenhouse a couple of weeks ago. It is time for growers to apply preventative sprays so they ship clean plants. It might also be worthwhile for you to, again, publish information about how home owners/commercial landscapers can deal with the disease in their gardens. Also, a list of alternative plants to plant in place on Impatiens if the disease infects the plants in garden plots.