Is this sentence correctly punctuated?His clothes were worn; mud and leaves infested them, and they were slightly tattered from his time in the woods.
It doesn't seem correct to me, though it is grammatically correct to use a semicolon between two closely related clauses. You have two sentences and might also use a period after "His clothes were worn." I suppose you could say "worn and tattered." You might be able to include everything in one sentence which would incorporate the facts that his clothes were tattered and covered with mud and leaves, showing how long he had been lost in the woods, or hiding in the woods.