This year that little worm may be the larvae for the Spotted Wing Drosophila (SWD) (aka Cherry Vinegar fly). The fly has been known to the area since 2009, and is common in many areas around the country now. The SWD attacks cherries, raspberries, blackberries, blueberries, strawberries, plums, grapes and nectarines. Breeding sites are found where there is overripe or fallen fruit. Fruits become infected near harvest time (that’s blueberries and raspberries now).
See videos for Spotted Wing Drosophila on the Oregon State University site.