My impatiens are wilting, not flowering, losing leaves have a powdery white
Have a white powdery substance on underside of leaf. What is it? And how should I treat it?
Certified GKH Gardening Expert
The powdery residue is from a fungal issue called powdery mildew. You can try treating the plant with neem oil. Here is more information: https://www.gardeningknowhow.com/plant-problems/disease/get-the-cure-for-powdery-mildew.htm