The leaves of my spinach plants are drying up and dying. The plants are in pots. I looked closely and saw fine blackish dust things on the leaves. They are dried up leaves and on one leaf, I saw a small larva inside the leaf. Is this a disease? I don't know what it is. Should I keep them separate from other plants? They were transplants and ever since the hot weather set in, they got that way.
Certified GKH Gardening Expert
"The black dust you describe sounds like sooty mold, which is a fungus brought about by pests. Neem oil will help with both the fungal issue and insect pest which may be causing it. This organic insecticide/fungicide is safe to use on edibles too. Here is more information: https://www.gardeningknowhow.com/plant-problems/disease/how-to-get-rid-of-sooty-mold.htm