Hello - we have received this question quite a bit lately. Here is a response from one of our Master Gardeners:

It sounds like the larvae of the spotted wing drosophila, which look like small, white worms. The following chemical controls are recommended. pyrethrins—These products provide about 80% control of SWD but have no residual activity. spinosad—This product generally provides 100% control and 5-7 days residual activity. Residual activity would be how long the product stays on the plant to kill the insect infestation. To avoid the infestation, pick fruit at regular intervals to prevent egg-laying opportunities and infestations. Avoid overripe fruit on plant. Clean up leftover, fallen and infested fruit. As with any pesticide, follow label directions carefully about when and how to apply. Wear protective clothing. The label should say how long after the application you can eat the non-infested fruit.

-Sharon, Master Gardener