Marionberry Disease

Asked October 15, 2017, 12:04 PM EDT

I have been struggling with a disease affecting my marionberries for years. So much so that I cut out all of the floricanes one spring just to avoid contaminating the new primocanes. It did not work. I am also very diligent about fall cleanup so as to avoid diseased material on the ground, etc. The canes are fairly productive each year, but definitely not as productive as they could be. Please tell me: 1. What is this disease? (See attached pictures) 2. What is the cure? 3. What is the best preventative program to avoid disease? I would not ony like to eliminate the disease but also prevent future recurrence. Thank you! Mike

Washington County Oregon marionberries

1 Response

Hello Mike,

It is not possible to conclusive diagnose a disease and thus recommend a proper control from pictures. I suggest you take a sample to your local OSU extension office and if the diagnosis cannot be conclusive, pay for a sample to be sent to the OSU Plant Clinic (http://plant-clinic.bpp.oregonstate.edu/) for identification.

Based solely on the pictures and thus lacking confidence, I think the leaf symptoms are typical for cane and leaf rust (assuming there was orange growth on the leaf's underside. The cane splitting may be due to cane damage (wound response) or cane blight. You can learn more about these diseases or problems at the PNW Disease Management Handbook wed site:
https://pnwhandbooks.org/plantdisease/host-and-disease-descriptions?title=Blackberry
Best wishes,