My aubergine plant, which has been in the garden, and pepper plant, which is in the greenhouse, have developed blackened leaves, which then drop off. I initially thought it was black fly, so I sprayed the affected plants with an insecticide. This condition has now spread to a chili plant in the greenhouse. Please help.
Pepper, Aubergine Plants
Certified GKH Gardening Expert
This could be sooty mold, which is indeed brought on by pests. Try treating with neem oil. this should take care of both the sooty mold fungus as well as whatever insect is attributing to the problem. Here is more information: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm