2 Raspberry questions
1. This year my raspberries (summer bearing) produced small and often crumbling fruit, and some of the canes have yellow intervein areas. I read that this could potentially be a virus or perhaps a micronutrient deficiency. The symptoms actually began last year, and slowly spread to most of the crop. I don't think its a N deficiency because the new primocanes are 10 - 12 feet tall! Should I send my leaves to be analyzed? If so, where? Or? (Note my plants are probably too dense - would thinning them help?) 2. I read in one of your pubs that one should not top primocanes in the summer. Why is that? I've done that in previous years because they are so tall and tend to droop over other plants - would that have caused problems? Thanks!
Thanks for your questions. According to Dr. Bernadine Strik (one of the authors of the OSU Extension publication Growing Raspberries in your Home Garden), you don't top primo canes during summer because it leads to branching and this reduces yield (in floricane-fruiting types), and delays the harvest to the point where it will be too late in primocane-fruiting types.
Regarding question 1, Dr. Strik says the crumbling is likely due to Raspberry Bushy Dwarf Virus. Here is a link to information from the PNW Plant Disease handbook regarding raspberry crumbly fruit viruses. https://pnwhandbooks.org/plantdisease/host-disease/raspberry-rubus-spp-crumbly-fruit
The Oregon Dept of Agriculture does provide a pay-for-service plant diagnostic option. Here is a link to that service