Sporulation on the undersides of leaves photo credit
First detection of downy mildew photo credit
5 weeks after detection photo credit

Downy Mildew


There have been reports of
Downy Mildew showing up on impatiens and double impatiens around Michigan.

Downy Mildew is a destructive foliar disease of impatiens and double impatiens that is capable of causing complete defoliation or plant collapse, in a short amount of time. The spores produced on the underside of infected leaves are easily dislodged and can be spread short distances by water splash and much longer distances by air currents.

At this time we are working on keeping our customers informed with all the knowledge available. This disease of impatiens has been a blow to our industry, which is beyond our control.

Once an impatiens has downy mildew, it cannot be cured. All infective plant, root, and debris in the garden should be placed in a plastic bag and destroyed. These plants should not be composted. Make note of the planting areas, and avoid re-planting impatiens in these beds next year. Spores in the flower beds that can survive temperatures to -15.

We will offer a large selection of alternative plants for your shady garden needs. Begonias, coleus, torenia, potato vine, salvia, pansy, viola, vinca, also wave petunias that require only about 4-5 hours of sun. New Guinea impatiens and Sunpatiens both are resilient to the downy mildew.

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