Lichens and moss do not harm the plants, but some find them quite unsightly. Lichen and moss typically begin to grow on plants that are all ready experiencing poor health. Lichens and mosses provide many benefits, such as a nesting, cover and food source for wildlife. For example, lacewing larvae -- beneficial predators that feed on undesirable insects -- use lichens as a protective cover. When manually removing the lichen or moss, refrain from pulling it off the tree or shrub and instead gently lift it up off the plant. This will avoid damage that can occur from jerking the lichen or moss off the branches. Furthermore, wait until the dormant stage of the tree or shrub to manually remove the lichens or moss. If the plant tolerates copper sprays, it can be used to reduce them. There are many different types of both and some can be sprayed, others will be unaffected by sprays. When applying the copper sulfate, thoroughly cover the entire lichen or moss to the point of runoff. Before using any chemicals to control lichens and mosses, read the specific instructions printed on the label. Following the manufactures recommended directions will increase the chemicals effectiveness and help prevent injury to the tree or shrub. Many times, merely improving the health and vigor of the infested tree or shrub will control the lichen or moss growing on the plant.