Question
At a marina on a creek off the Ohio River near Ripley, OH, boats that are moored near a large Scyamore tree are getting lots of reddish brown spots most weekends.  Could the tree cause this problem?  Those away from the tree do not have the problem.  The spots are cleared by bleach but it takes the wax off the boats.  Appreciate your help in this seasonal problem.

Answer
If the spots are sticky these are honeydew caused by scales or aphids on the tree. These insects suck the plant juices form the plant and secrete a substance called honeydew which is high in sugar content. About all that could be done is treat the tree with an insecticide for the aphids or scales. More than likely this would be difficult since the tree is on the water bank. You will just have to park the boats some where else or cover them. Sorry.