My raspberries didn’t bud above about 2 feet off of last year’s canes. This section of plants has done very well the past few years, I cut off the dead canes and thinned to a few canes per root at end of winter. Is this disease? Winter kill? Not enough water?
I agree it looks like aphids doing the damage, especially if this is a recent development. You may wish to do some selective pruning on the flush of new growth to improve air flow there, which would also give you some more space for aphid-related management too.