Q.What Do I Do With Marion Blackberries That Have Have Mushy Tan Colored Spots On The Fruit?
I am from the northwest so I am familiar with black berries but I have never seen this before. The individual segments on the berries are a tan color and mushy but the pips are extra hard if you smash the berry open. These are grown in full sun rows in Northern California where it is hot and dry. They have a drip system that’s only run a couple times a week for about 20min. Its producing a huge amount of berries but they have this weird affliction I haven’t been able to identify. I help with this garden with another person who is normally the one who takes care of them. So I dont know what kind of fertilizer he uses.

Certified GKH Gardening Expert
This resembles Anthracnose, but I would take samples up to your local extension service: