One of the other members of the garden group thinks our raspberry patch has raspberry mosaic virus.
This is what the leaves look like:
I’ve noticed this in years past, but we assumed it was chlorosis, which looks like this:
Chlorosis is yellowing of the leaf in between the veins. It is often a sign of iron deficiency, and can often occur places with cool wet soil. This raspberry patch is right next to a sewer drain, and it’s often a bit boggier and cooler than other parts of the garden, so chlorosis/iron-deficiency made sense. I don’t believe we ever tried to do anything to correct the nutrient deficiency — there are so many other things to do in the garden — and it didn’t seem to impact our raspberry yields too much.
But this year, one of the other garden members did some more research and decided it was Raspberry Mosaic Virus.
Raspberry mosaic virus is actually a combination of viruses. The viruses are spread by aphids or nematodes. It is often described as “mottling” or “spots” on raspberry leaves and “curling” or “blistering” of the leaf. Also, the plants will have decreased fruit production. There is no treatment for raspberry mosaic virus, and the only way to get rid of it is to pull out the plants. Here are some images from the internet of raspberries with mosaic leaf virus:
Hmmm… Those pictures don’t look like our leaves. After seeing that, I initially thought we were in the clear. But the more I read about raspberry viruses, it sounds like other viruses (and maybe raspberry mosaic virus too) can also present as yellowing between the veins, just like ours. The image below is from a plant with Bushy Dwarf Virus
Looks pretty similar.
So, how do we tell the difference? How do we know if we should rip out all the plants, or just amend the soil?
According to Which? Gardening, it’s more likely to be the virus if it only affects some varieties more than other, and it’s more likely to be iron-deficiency if it affects all plants equally, and if it happens within the first two or three years of planting. Hmmm….not all of the raspberry bushes in the patch have it, but its hard to tell which plants are of which variety, so I don’t know if some varieties are affected more than others. It’s definitely been more than two or three years since planting, though, so that points toward a virus. I’m not sure any of that was helpful.
I think the best way to tell would be to get the soil tested to determine if there is a nutrient deficiency, but I doubt the garden group will bother with that. Do you have any experience with raspberry mosaic virus or any other viruses? Any advice would be appreciated.