Q.I have crumbly raspberries
The raspberry plants are thorn-less and only bear fruit for about 5 weeks mid-summer. They have provided good to excellent berries for years, but in the past few years more and more (particularly in one row) have smaller berries that crumble when picked. It seemed that more and more in that row were being affected, so in the fall I dug out all the plants in that row. I read that to eliminate the virus, or whatever is causing the problem, I should cover that area of soil and let it sit for a year. Can you give me more information on this procedure–what to cover it with and how to know if the problem is solved?
There are many reasons for crumbly raspberries including Tarnished Plant Bug feeding, Raspberry Bushy Dwarf Virus, Tomato Ringspot Virus, or Poor Pollination.
If it's raspberry busy dwarf virus, this virus is a seed and pollen borne virus that spreads during bloom. You did the right thing by removing the plants to prevent the possibility of healthy plants becoming infected during pollination, now you can replant with healthy nursery stock and may want to consider RBDV resistant varieties such as ‘Willamette’, ‘Haida’, and ‘Chilcotin’. My research did not indicate that covering the soil and refraining from replanting was necessary for RBDV probably because it is a seed and pollen borne virus.
Here is more information on the RBDV virus:
https://www.gardeningknowhow.com/edible/fruits/raspberry/raspberry-bushy-dwarf-virus.htm
On the other hand, if it's tomato ringspot virus, then you are supposed to not plant in the affected area for two years. Some, and I think this is more for commercial applications, spray the soil at a certain depth with a fumigant nematicide and replant with resistant varieties. You can read more about tomato ringspot here:
https://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-ringspot-virus.htm
You can read more about crumbly raspberries and the prescribed treatment at the following links:
https://www.gardeningknowhow.com/edible/fruits/raspberry/reasons-for-crumbly-berries.htm
http://www.fruit.cornell.edu/berrytool/raspberry/flowersfruits/Raspcrumble.htm
For more information on the care of raspberries, please visit the following link:
https://www.gardeningknowhow.com/edible/fruits/raspberry/care-of-raspberry-plants.htm
