Your Impatiens Might Have Downy Mildew If …

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Notice the leaf curling

Growers across the country are scrambling for solutions, with the discovery of downy mildew on impatiens in the U.S. landscape. Look for these symptoms in the greenhouse when you’re scouting your impatiens crop this year:

• Plant foliage that’s yellowish or pale green in color

• Leaves that curl downward

• Leaves that are distorted

• Undersides of leaves that have white or light gray fuzz present

• New and emerging leaves that are small and a discolored yellow or pale green

• Flower buds that fail to form

• Stunted plant growth

Downy Mildew On Impatiens: Resources And Advice Page

Click here for our Downy Mildew On Impatiens: Resources And Advice page, which includes all our coverage of the 20102-13 outbreak, including what to do if you find impatiens downy mildew on your crop and alternative crops to grow. 

If you see one or more of these symptoms on a plant, immediately seal it in a plastic bag before removing it from the greenhouse. Get it to a diagnostic lab for further testing.

Additionally, when spraying for downy mildew, there are three important things to remember when applying fungicides:

1. Apply fungicides preventatively.

2. Rotate among products with different modes of action to prevent resistance.

3. Be timely in re-applications.

Laura Drotleff is editor of Greenhouse Grower.
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    2 comments on “Your Impatiens Might Have Downy Mildew If …

    1. Janelle

      I actually have a question about downy mildew not a comment. We have a small garden center in Ohio and have already thrown away or first round of impatien plugs we received from a broker in Michigan. They appeared to have downy mildew. We purchased a second round of plugs from another supplier and they seem to be fine until today 4/22. I watered a number of flat and other things but noticed a fine cloud or poof of smoke when I attempted to water the new impatiens. Nothing else in the greenhouse reacted like that to the watering that we do daily. Is that another sign of mildew and will it infect our other plants? What would you recommend using on the impatiens or possibly the entire greenhouse including veggies?