Citrus sooty mold isn’t actually a plant disease but a black, powdery fungus that grows on branches, leaves and fruit. The fungus is unsightly, but it generally does little harm and the fruit is edible. However, a severe coating of fungus can block light, thus affecting plant growth. Most importantly, citrus with sooty mold is a sure sign that your citrus tree has been invaded by harmful insects. Read on for tips on controlling citrus sooty mold, along with the insects that create conditions ripe for fungal growth.
Citrus Sooty Mold Info
Citrus with sooty mold is the result of an infestation of aphids or other types of sap-sucking insects. As the pests dine on the sweet juices, they excrete sticky “honeydew” that attracts the growth of ugly black mold.
Sooty mold fungus can grow wherever the honeydew drips – on sidewalks, lawn furniture, or anything else under the tree.
Citrus Sooty Mold Treatment
If you want to get rid of sooty mold on citrus, the first step is to eliminate the honeydew-producing insects. While aphids are often guilty, honeydew is also left behind by scale, whiteflies, mealybugs and various other pests.
Neem oil, horticultural soap or insecticidal sprays are effective ways of controlling pests, although eradication generally requires more than one application.
It’s also important to keep ants in check. Ants love the sweet honeydew, and they will actually protect the honeydew-producing insects from ladybugs, lacewings and other beneficial insects, thus ensuring a continual supply of the gooey stuff.
Control ants by placing ant bait under the tree. You can also wrap sticky tape around the trunk to prevent the ants from crawling up into the tree.
Once the pests are controlled, the sooty mold will usually wear away on its own. However, you may be able to speed the process by spraying the tree with a strong stream of water, or water with a little detergent mixed in. A timely rainfall will do a world of good.
You can also improve the appearance of the tree by pruning damaged growth.