Homeowner Forum / Lawn and Garden / March 2008

We have a dwarf cherry tree that hosted some strange parasites last
year.  They were small, black, flat, shiny, slow-moving worms that
looked just like the flatworms that sometimes threatened Muldur on the
X-Files.  They ate lace patterns on the leaves.  Rosebush dust put
them to rout last year.

Now the buds on the tree are opening and I am concerned about the
infestation returning.  I have Googled around but have not been able
to isolate their identity or find a specific for their prevention.
Does anyone here have a clue?  TIA.