Raspberry disease

Question: I have many rows of healthy raspberries.  One large section of one row seems unhealthy as it  has stunted growth with hard, dry, underformed berries that don't look like they will mature.  Do you have any idea what the problem is?  All of the berry rows receive the same amount of water, fertilizer and sun.  I have grown raspberries and blackberries for years and have never seen this.

responder: Leo Sherry  Replied June 13, 2023, 1:09 AM EDT
response: Hello! From what you are describing, it sounds like your raspberries are experiencing crumbly fruit. The possible causes are viruses, poor pollination, tarnished plant bugs, two spotted spider mites, boron deficiency, and sometimes Botrytis. I doubt that poor pollination or boron deficiency is the problem because only a small section of your plants are affected. Have you seen any bugs on the affected plants? Tarnished plant bugs, a subset of Lygus bugs, are described here: Blackberry and Raspberry-Lygus bug | Pacific Northwest Pest Management Handbooks. Two spotted spider mites are described here: Blackberry and Raspberry-Spider mite | Pacific Northwest Pest Management Handbooks. The spider mites do not fly, the damage they do starts from the bottom of the plant and moves upwards. They must crawl between plants, so the damage pattern could match what you are seeing. If you had a Botrytis problem, I think you would see more issues than just malformed berries. The remaining cause is viruses. The possible viruses are Raspberry bushy dwarf virus (RBDV), Raspberry leaf mottle virus (RLMV), Raspberry latent virus (RpLV), and/or Black raspberry necrosis virus (BRNV). If virus(es) are the cause, it is typical for the plant to be affected by a combination of these viruses, rather than just one. Unfortunately, it’s difficult to diagnose viruses without a lab test.  Raspberry (Rubus spp.)-Crumbly Fruit | Pacific Northwest Pest Management Handbooks Some more resources: Crumbly raspberry disorder being seen across Michigan - MSU Extension Raspberries: Fruits is small, deformed, or crumbly | Berry Diagnostic Tool Raspberry viruses | Berry Diagnostic Tool I hope this is helpful! Regards, Leo Sherry OSU Extension Master Gardener Volunteer

responder: The Question Asker Replied June 13, 2023, 12:51 PM EDT
response: Leo, Thank you for the information and resources.  I am thinking that some of the berries may have a virus.  Is there somewhere ( I live in Salem) that I could take a plant for diagnosis?If it is a virus, I  am assuming I would remove the affected plants.  Are the other healthy looking plants doomed to succumb to the virus?I also have new plantings of thornless blackberries that are not far away from the raspberry rows.  I am trying Columbia Giant for the first time this year. I hope they will be okay. If there is nowhere to take a sample plant in Salem would I be able to bring one to another location?  I really want to diagnose and stop the problem if at all possible.JanOn Mon, Jun 12, 2023 at 10:09 PM Ask Extension <<personal data hidden>> wrote:

responder: Leo Sherry  Replied June 14, 2023, 2:41 AM EDT
response: Hello! The closest analytical lab that can diagnose plant disease is the OSU Plant Clinic in Corvallis. It looks like samples can also be mailed to them. College of Agricultural Sciences OSU Plant Clinic  I also found this list for analytical laboratories, but they are farther away than OSU. Analytical Laboratories Serving Oregon | OSU Extension Catalog  Blackberries are generally less affected by the viruses, so hopefully you will be okay there. If they are infected with only one of them, they may be completely symptomless. If it is a virus problem, it is possible they were a source. (The paragraph above the cultural control section in here describes it: Raspberry (Rubus spp.)-Crumbly Fruit | Pacific Northwest Pest Management Handbooks, same resource as my previous email.)  If it is a virus spread by aphids, controlling aphid population can help slow the transmission if removal of the plant is not a good option. If it is a virus spread by pollinators, removing the plant would be the best move, unfortunately. Regards, Leo Sherry OSU Extension Master Gardener Volunteer