I didn't think there was a cure for the downey mildew. I haven't grown the walleriana since mine had the disease in 2012. But I don't know if I could ever get rid of the balsamina: they reseed like crazy every year. I haven't planted them in probably 6 or 8 years but I get hundreds of volunteers every year. Those usually look diseased by late summer but I'm pretty sure it's powdery mildew. I've tried treating them with GreenCure and they got better.
Karen
