Darryn writes:
Alas this year the fruit fly has already started to get it and the
fruits not quite ripe yet but I think it will only be a week or so
more.

Is it too late to spray the tree for fruit fly now?

Depends. You will have to look at the withholding period specified on
the bottle, different sprays have vastly differing periods before you
can consume the fruit. You also have to expect there will be some
developed lavae dead inside the fruit, I expect. Inspect carefully, or
just eat and be damned! What you don't see won't hurt you.

Fly strike makes the fruit ripen earlier, by just a few days, so you
might find that all but the first maturing plums are quite okay if you
can get to and spray straight away.
--
John Savage (for email, replace "ks" with "k" and delete "n")