Raspberry Ringspot

Raspberry ringspot (RRSV) is a viral disease that infects an odd assortment of plants. While raspberries, followed closely by strawberries and boysenberries, are vulnerable, cherry trees, members of the grape family (Vitis), and Narcissus can also be infected.
 
Either way, this is an important distinction because planting raspberries or strawberries near your grapevines, cherries, or adding a little springtime color with some daffodils, jonquils, or narcissus, can significantly increase the odds of your plants becoming infected and spreading this disease.
 
Did you know that the raspberry ringspot virus (Nepovirus rubi) is a close relation to the tomato ringspot virus (N. lycopersici)? They are so closely related that raspberry plants can catch tomato ringspot. I don’t know if tomatoes can catch raspberry ringspot, but I wouldn’t be surprised.
 
But it brings up an important point about raspberry plants. They are rugged once established. Very often, they will be infected with multiple diseases before we notice anything is wrong. It is the older, less virile plants that are more likely to catch raspberry ringspot. Once they catch it, however, it can spread.
 
How to identify raspberry ringspot
 
Like other ringspot diseases, the raspberry ringspot virus causes target-shaped, oval, or abstract rings that can appear on leaves or fruit, depending on the plant and virus involved. [Unfortunately, I could not find an image I could use.] Other symptoms include an overall failure to thrive and crumbly fruit.
 
Managing raspberry ringspot
 
Besides watching where you plant your raspberries, you can reduce the odds of ringspot by keeping wild brambles out of the area and only using certified pest- and disease-free stock. But the problem may already be in your soil.
 
RRSV is carried by dagger nematodes. These tiny buggers move through the soil, spreading disease and mayhem in their wake. OK, it’s a very small mayhem, but you get the idea. Dagger nematodes have a reputation for being the most destructive of their species when it comes to plants.
 
Unfortunately, they are hard to get rid of. While you can apply a nematicide (nematode poison), it won’t kill all of them. Any that are left can reproduce exponentially and asexually, so it’s an uphill battle.
 
The only sure-fire way is to combine the nematicide with two years of leaving the area fallow, or unused. This will starve them out. Crop rotation can help, too.
 
At this time, I am unaware of any resistant varieties, so keep your plants healthy by choosing varieties suited to your microclimate and ensuring they have everything they need to thrive.