Lichens, mosses, and algae
Trees or limbs affected by lichens, mosses, and algae have grayish, greenish, or orangish tissue growing
on or hanging from the bark. Lichens, mosses, and algae often grow on older trees and are generally harmless to the host plant.
soaps developed specifically to control mosses, lichens, and algae are available.
Greenish algae hanging on tree trunk