Hi! Two possibilities from what I've researched. One possibility is strawberry sap beetle, the other is omnivorous leaftier ("strawberry fruitworm"). Information on the strawberry sap beetle can be found here (in the middle of the page): http://ohioline.osu.edu/b861/b861_14.html The larvae of this beetle are white with a brown head and up to 1/10 of an inch long. The omnivorous leaftier according to the 2001 PNW Insect Management Handbook has mature larvae that are 3/4 inch long, light cream in colour, with tan heads which web and feed in growing plant tips and strawberry fruits as they ripen. For the Pacific Northwest, it suggests to look for leaftiers in the first week of May, but if the strawberries you have are from a more moderate clime (California, perhaps?) they may be a persistent problem.
