Here’s a sneak peek from our forthcoming November issue:
Downy mildew is a fungus-like organism related to pythium and phytopthra that attacks impatiens wallriana and interspecific hybrids.
The disease has been identified in 26 states as of press time. Most are clustered on the eastern seaboard, from Massachusetts to Florida, then sweeping through the Midwest up into Michigan. Earlier this year, it was identified for the first time in Oregon. Colleen Warfield, corporate pathologist at Ball Horticulture, says high-risk areas this year are Illinois, Michigan, Southern Georgia and Louisiana.
When impatiens started dying late last year, many contractors thought it was just frost damage, or a fluke. “Everyone knew there was a problem but no one thought this was a disease,” says Warfield. “Now we’ve got it in all these states.”
The photo above shows what happens to infected impatiens. Not good.
To help, Ball has a quick FAQ on best practcies for landscapers to manage the disease in the landscape.
Photo credit: Alan S. Windham, UT Extension