I suspect the recently arrived Spotted wing drosophila, SWD.

It's a close relative of the nuisance fruit fly. but this one damages ripening fruits still on the plant.

Relatively recent--they have been in Oregon fruits for at least 5 years now. Your worm is very likely the above-mentioned SWD.

These flies (in the PNW) appear in numbers in early July, so earlier-ripening caneberries are not affected.

They are not causing your withering and undersized berries.

A salt water solution will cause them to emerge. So will putting them in the fridge or the freezer, then they can be picked, rinsed, or brushed off. Cooling also stops their feeding and growing. All of this is not 100% effective, if you require that.

Spinosad spray is an organic control.

Cutting the canes will not help. Putting out apple cider vinegar traps with a drop of unscented soap can reduce the numbers bothering the fruit.

The nearby cucumbers are safe and I haven't seen any reports of tomato damage, but I wouldn't put it past them in the future.

http://spottedwing.org/ has a lot of info from OSU ag.

Thanks for the replies and ideas.

I'll probably hit the plants with the organic spray AND build some traps.

Just wondering how much luck folks have had with homemade vs. store bought traps

Please cross your fingers that these evil SWDs stay in the raspberry patch; if they invade the tomatoes (which are so difficult to grow in the PNW and which are looking great and ready to start producing fruit) I will become a medieval monster.

...although most tomatoes in your region ripen late enough that the SWD population is in decline for the year. I have read of them going on grapes. All depends on the fruit's skin strength.

For traps, I use some small 8-ouce threaded-lid plastic cups, drill some 3/16" holes near the rim, add the liquids (you don't need more than an ounce or so per trap)(refresh the trap about once a week) and hang in a shady part of the berry patch. Re-usable year after year. Haven't tried store-bought, the homemade are very effective.

This may be of interest --

Here is a link that might be useful: Recognize Fruit Damage from Spotted Wing Drosophila (SWD)

This also -

Here is a link that might be useful: Protecting Garden Fruits from Spotted Wing Drosophila

Thank you Jean. Very informative.
I'll be on the lookout for em'.
It seems a widespread control is almost hopeless with our Himalayan blackberries growing everywhere.
Mike

I am fighting this creature already three years. Last year it invaded even very sour sea buckthorn.
Traps help a little bit, but not all of them go to traps.
Flies are on fruits when they are almost ripe and I hate spray raspberries even with organic spinosad.
Picking all bad berries will prevent multiplying.
I am going to create cage with mosquitos netting next year. It's what I am doing to protect current bushes from gooseberry fly. I need to do it for strawberry as well. Mess.

Sorry to hear about the infestation of your sea buckthorn fruit; I grew those a number of years ago and tens of pounds of fruit can be involved.

Keep in mind that the fully-grown larvae drop to the ground and pupate overwinter near the original plants. Caging would not completely prevent an infestation next year unless the netting is gathered around the trunks near the ground.

Same goes for the gooseberry fly; these are pupating right now under your plants.

I have read that SWD overwinter as adult not in the soil.
I have managed to get rid of gooseberry fly with netting, but it's not so easy with raspberry because they need pollination. Will cover tomorrow sea buchthorn and need to think what to do with fall raspberry.