Fungus on Apple Tree

Asked March 12, 2019, 3:24 PM EDT

I have a fungus growing on my apple tree. Do you know what it is and how to kill it. I have attached a photo. Thank you Joel LaRocco

Jefferson County Kentucky

1 Response

This appears to be a lichen.

Lichens are a plant composed of a fungus, an alga, and quite commonly, a yeast that live together in the same body. Lichens often appear as green to gray-green leafy or crusty growths on the trunks or branches of plants. They are not harmful to the plant, and are merely using the plant as a place to anchor.

Typically, lichens occur on plants that are declining in health or vigor. They are in no way responsible for the poor health of the plant, but can indicate that there is a stressor. Less vigorous plants tend to be more open, increasing sunlight penetration and subsequent lichen growth.

Treatment: Controls are not necessary, since lichens are not harming the plant. Lichens will gradually disappear if plant health is restored. Remember they will probably reappear if you do not correct the true cause of the plant’s decline.