How to Kill Lichen on Apple Trees
Lichen is harmless to your apple tree since it not a parasite like true moss that feeds on its host’s valuable water and nutrients. However, lichen is a sign that your apple tree is not growing as it should. The tree’s canopy is allowing light to penetrate the trunk and is therefore creating optimum conditions for lichen to grow. After you successfully kill the lichen on your apple tree, revive your apple tree to full health by proper pruning, watering and fertilizing so the lichen does not return.
Scrub the lichen off your tree with a soft nylon brush. Do not harm the bark on the tree in the process.
Wet down the remaining lichen with a hose. This will help the lichen absorb the treatment you are going to use to kill it.
Apply the lichen with a fungicide that contains copper. Kocide DF is an example of a copper-containing fungicide that kills lichen. Such fungicides are usually not labeled to kill lichen, but they are approved to kill other similar fungi such as ball moss. Follow label instructions and do not spray the apples themselves.
Apply a baking soda and water mixture as an alternative to the copper-containing fungicide. Mix in a spray bottle 1/2 cup of baking soda per gallon of water and spray the lichen.
Kill Lichens And Fungus Growth On Apple Trees?
Copper sulfate is readily obtained online or at most garden stores, and is easiest to use in a fluid concentrate form. Although it is safe to use to treat fungus and lichen, keep children and pets away from it during application, as it can irritate skin and eyes, and can cause vomiting, and infrequently poisoning, when ingested. Lichens and fungi thrive in dark, shady, sheltered areas. If your trees are in no immediate danger and you prefer a natural route, wait for the next pruning season, and prune your trees to allow significantly more sunlight to penetrate to the trunk and branches, creating an inhospitable environment. Many brands of fungicide are available on the market for treating fungus on apple trees. If simple treatments or creating more sunlight does not do the trick, you may wish to scrape your trees.
- Scrub brush
- Copper fungicide
- Spray bottle
- Baking soda
- Texas A&M University: Parasites
- PlantAnswers.com: Ball Moss on Your Trees
- Ohio State University Extension: How to Care for Tree Wounds
- University of Vermont Extension: Key Arthropods and Diseases Affecting Apples
- University of Rhode Island Landscape Horticulture Program: Home Tree and Small Fruit Pest Management Guide