Thursday, October 15, 2009
Impatiens Downey Mildew.
3 seasons back we first heard of a Downey Midew disease specific to Impatiens walleriana (It does not affect New Guinea Impatiens). We are somewhat isolated here in Keysborough so we didn’t see any until very late that season. The following year was tough and Impatiens production was nearly wiped out. Last year it appeared that the disease had gone away again but… It’s Back!
The good news from our perspective is that so far we are clean, despite the weather conditions being ideal for the development of Downey Mildew.
The bad news is if you have had diseased plants in your garden you will have to take particular care to ensure clean plants you introduce are not immediately infected. HYGENE! You have to remove, dump, destroy all infected plants and clean pots and surrounds with household disinfectant. It’s best not to reuse garden beds for a number of years.
The only other tip I have is keep plants as dry as possible (HA, HA!), this includes watering early in the day to ensure maximum time for plants to dry out and keep them in a full/high light sun position. Full sun will not bother Impatiens until we get into January type conditions, just be careful of windy days.
By the way, I nicked the pic of the underside of an infected Impatiens leaf from a web site and have forgotten where. My appologies.