IDM was found in GA this past weekend on recently purchased plants. Presumably, the pathogen was present when they were purchased from the retail garden center. John Olive, Director of the Ornamental Horticulture Research Center, says the disease has not been terrible the past couple of years in Mobile or the surrounding areas. He has seen cases of it but has also seen Impatiens making it the whole summer without the disease. One reason may be fewer plants available because fewer greenhouses are growing them for resale. The disease showing up this early may be a warning.
IDM causes Impatiens leaves to yellow and quickly defoliate. A downy, white fungal growth can be seen on the back of the yellowed leaves. The plant will completely defoliate and only green, erect stems will remain. For more information contact your local Extension Office.