DATE:   11/27/96
WRITER: Bob Polomski, (864) 656-2604

Licking a Lichen Problem

     Q.  I have a sickly 10-year-old dogwood that seems to be
under attack by a number of colorful, fungus-like growths on the
trunk and branches. What are these growths and how can I control
them?  
     A:  Your trees could be colonized by lichens. These
ominous-looking though harmless organisms consist of a fungus and
a green or blue-green alga which live in association with one
another, looking like a single plant. Lichens often appear leafy
or crusty and are colored gray, green, yellow or white. 
     Typically lichens can be found on dead or declining trees,
on rocks, or on the ground. Their presence on failing trees is a
sign, but never the cause, of poor plant health. The reduction of
plant vigor results in a more open canopy which increases
sunlight penetration and subsequent lichen growth.
     You can remove the lichens from your tree with a stiff
brush, but they will probably reappear if you do not determine
the cause of decline and correct it.
     Restoring your dogwood should increase the size and number
of leaves and eventually lead to the gradual disappearance of
lichens.
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     If you have gardening questions or comments, write to 
Agricultural News & Publications, A-101 Poole Agricultural
Center, Box 340311, Clemson University, Clemson, S.C. 29634-0311.
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