SPRING – SUMMER 2013 - Grow Greenstreet

ALErT: impOrTAnT nEwS
Impatiens Downy mildew-
Impact on the Landscape Trade
Background:
Impatiens Downy Mildew (IDM) is a destructive
disease affecting Impatiens walleriana. This
disease is capable of causing complete
defoliation or plant collapse especially in
landscape plantings under moist conditions
and cool nights
Plants Affected:
All varieties of Impatiens walleriana
(common garden impatiens) and
interspecific hybrids such as double
impatiens. New Guinea Impatiens are not
affected by IDM.
How Does IDm Spread?
Spread of the disease in the landscape occurs
with splashing water as well as the spread of
spores on air currents. Spores may be present
in landscape beds that were not cleaned
thoroughly in the fall which may result in the
infection of new plantings.
Symptoms:
See photos showing the undersides of a leaf
and then landscape beds showing the
progression of the disease.
At Greenstreet Growers we are following
recommendations for the best cultural and
chemical practices to provide clean, disease
free Impatiens. Although we can treat
Impatiens to provide protection for a limited
time after leaving our greenhouses, we cannot
guarantee the plants will not be infected once
in the landscape. Please go the web site of
the American Floral Endowment (www.
endowment.org) or contact your local
extension service for more information on
Impatiens Downy Mildew in the landscape.
8 Greenstreet Growers l sprinG 2013 Online Orders: www.GrowGreenstreet.com