I have a number of plants that have yellowing and dying leaves near the base of the plant. I am most concerned about my hibiscus and fig tree, also affecting a unknown tropical plant. earlier this year I had a infestation of spider mits that killed a palm. Assuming it could be spider mites, I purchases an insect spray (AIM House Plant Insect spray containing pyrethrin and piperonyl butoxide) and have been spraying the plants with no help. The pattern of yellowing doesn't seem to be related to the spraying as it is only th bottom leaves. I can't see any bugs on the leaves but some do have small white and black spots. Any ideas on what is wrong with the plants or how I could save them??
