Hello everyone :-) I was hoping someone could point me in the right direction on how to "clean/treat" my trees properly. I've been noticing "black" leaves on my grapefruit tree and orange tree. Couple of garden stores that I have went to don't know what to do, and I also got advice from a gardener who said, "it's just dirty, shoot it down with water". The black leaves are actually a film that's over the leaf. I can scrape it off and reveal the green leaves. I also tried for three years pruning the "infected" parts of the trees but it reappears again. Can anyone help? I'll do my best to post a picture onto a thread. Thank You for your time reading.
Your tree has Sooty Mold, which is a fungus that grown on the excretions of insects. Therefore, control the insects and you will control the Sooty Mold. You can look up Sooty Mold on the internet. Sooty Mold is quite common. An application of a horticultural oil such as Ultra Fine, in the early morning or in the later evening will control the insect problem, and soften the mold at the same time. Do not spray the tree in the heat of the day. Then you can flush most of the mold off with a forceful spray with the hose. Sooty Mold does not cause much harm to the tree, other than reduce the amount of photosynthesis the green leaves can produce. - Millet
