Marion berry die-back
It appears as though a cane-boring larvae has damaged my Marion berries. Can you confirm this from the attached photos of presumed sites of entry (or exit?) and cocoon? I’ve noticed similar markings on my raspberry canes recently, but not with as significant die-back yet. If you advise a treatment for the Marion berries, should a similar treatment be applied to the raspberries? Thanks, Lincoln Thomas Cedar Hills (Beaverton ish)
Washington County Oregon marionberries
There could be a couple of insects that do a similar damage, for complete confirmation, I suggest you send or take samples to the OSU plant clinic. It's hard for me to give you a diagnosis from a photo. There is a new pest, the Rose Stem Girdler that is attacking all Rubus in the valley. Being a new pest, I'm not sure there are products labeled for use on it already, but you can email Justin O'Dea <firstname.lastname@example.org> since he's been working with it quite a bit this last year.
I believe the best option suggested so far was pruning and disposal (burning) of the sick canes, but I'm sure he can give you more details.