A single spraying in Spring will not do the job. You have to set up a spray schedule
like every few weeks from after blossom fall through a week or so before picking.
It sound like either apple maggot or codling moth worms. I usually see the end result
of this infestation as rotten insides of the apples. For now, clean up all the infected
fruit on the tree and on the ground and dispose of it. If there are any clean apples left, you can
try spraying with an insecticide. I use a strong chemical called Imidan
which you can only get at orchard supply outlets, but something like Sevin might also
do some good. Be sure to wear protective gear and breathing devices when spraying.

Sherwin D.

Anna wrote:

My brother-in-law picked a couple of his apples and cut them open. They had
small white worms with black spots in them. He said he sprayed the trees in
the spring. I don't know what he sprayed with or what these little worms
are. I don't even know what type of apple trees that he has. I do know
that they are young trees, maybe three years old.
Is there somewhere to research this? We live in what I think is zone 8.
Grants Pass, Oregon 97526.
We would be glad for any help.