By Plantlife
Midlothian,
United Kingdom 
Hello There
All the "Busy Lizzies" in my baskets and tubs have gone a bit weird! They've gone stalky and black and the buds have stopped flowering. Could this be the result of so much rain rotting them?
10 Aug, 2011
Answers
http://blog.gardenersworld.com/2008/09/08/ap-impatiens-08092008/
10 Aug, 2011
In Garden News there is a two page spread on"is the end nigh for busy lizzies".Apparently the downy mildew virus will not effect other plants but if your plants have succumbed they must be burnt as the spores can get into the soil.Dont put onto compost heap
10 Aug, 2011
Not just downy mildew affecting them - Necrotic Spot and Tomato Spotted Wilt virus, transmitted by Western thrips, are proving to be major problems too. Note that Downy Mildew is not a virus, but a fungal infection.
11 Aug, 2011
I'm afraid there seems to be a virus affecting busy lizzies this year, causing the symptoms you describe.
10 Aug, 2011