We have some Apple trees that have lots of Lichen on them. It appears to be killing the tree. The Lichen is blue. Can you tell me how the stop it? Why is the tree dieing?
Howdy Mr/Ms, Your apple tree is killed by other things; could be weather related, could be disease could be cultural practices, anything but lichens. Lichens are epiphytic, in other words they just use the apple truck or branches for anchoring and do not in anyway rob the host nor prevent the host from functioning. Peace Thean
The lichen may not be the actual killer of the tree, but lots of mites and insects hide in the lichen and they can destroy the tree. So it is best to get rid of the lichen somehow. The only suggestions I have found online are ......use a pressure washer ......spray with copper sulphate ......fertilize the tree or shrub because lichen start on unhealthy plants.
Have the "experts" ever considered they are barking up the wrong tree with regard to lichens? While they may be "harmless" to mature large trees with thick bark, how about young ornamental or fruit trees with thin bark? Couldn't the prolonged moisture contact under the lichens harm the bark? I believe I observe this on my Kwanzan cherries, Korean dogwoods, Thundercloud plums and crabapples. The [over]use of my sprinkler system undoubtadly contributed to the problem in my yard, and modification of watering seems to have helped. (I realize rain and mist are the likely culprits in the Pacific Northwest.) But gentle scraping and the spray application of chlorthalonil also have been needed. (I started with the chlorthalonil because I had it to treat my roses; copper-sulfate seems to be recommended.) The following are threads I turned up on a Google search that may be useful: http://www.gardenopus.com/Lichen.htm.
