Do my dry bean plants have a virus or other disease?
I have three varieties of dry beans planted, and the leaves of one of them, Vermont cranberry, look like they have some sort of virus or other disease. Other varieties right next to them (black coco and silver cloud canellini) look fine. Can you give me an idea what it might be and whether it might require action. The plants look healthy otherwise.
Caragh B. Fitzgerald, Associate Extension Professor
I shared your photo with the plant pathologist in our Plant Disease Diagnostic Lab. While those beans could be showing the effects of virus, it could also be spider mite damage. The photo wasn’t clear enough to be sure, and a physical sample might be needed. (See information about how to send a sample to the diagnostic lab). Neither virus or spider mites would require management at this point, though you will want to collect and destroy the plants after you are finished harvesting. If it’s a virus, that won’t overwinter, but mites could, if the plant material isn’t well composted. The next generation of mites could then blow into the garden next year. Some general information about viruses, spider mites, and other bean pests can be found in this fact sheet from University of Minnesota Extension.