"Sammy25" wrote
Last summer I bought a cherry tree, after a few weeks i noticed the
leaves began to roll up, when i opened them there where lots of little
black bugs in them. The leaves then began to turn yellow and fall off
the tree before the end of August. This is my first fruit tree and i was
wondering if there is any thing I should do to prevent this happening
this year.

The cause is Cherry Blackfly which overwinters on the cherry tree as eggs.
Check for the aphids and then when found spray thoroughly with any
anti-aphid spray and keep checking (and possibly spraying again) through the
summer. In the old days you would use a winter tar oil wash and zap them
with chemical stuff no longer available.

--
Regards
Bob Hobden
W.of London. UK