Have you ever had a dry bean crop that looked healthy but resulted in disappointing yields? Have you seen stunted or yellowing patches, but could not identify the cause? If so, you may want to look for soybean cyst nematode (SCN).
Researchers in Ontario and the US have shown that SCN is not just a soybean pest, it also reproduces on dry beans. SCN saps nutrients from the plant and can restrict root growth. There may or may not be visible above ground symptoms when beans are infected with SCN.
The impact of SCN on dry beans depends on the market class, and may also depend on the specific variety. AAFC researchers planted 40 dry bean varieties in SCN infested fields in 2010-2011, and about half had cyst counts similar to the SCN-susceptible soybean variety. These included cranberry, dark red kidney, and white bean varieties. Other trials have shown that adzuki beans are very susceptible to SCN, more so than susceptible soybeans
In studies conducted at North Dakota State University using 24 varieties (white, black, kidney and pinto), SCN developed normally on all classes and varieties of beans. Kidney beans had high numbers of female cysts, similar to susceptible soybeans. SCN reproduction was lowest on black beans. The different white bean varieties had a wide range of female SCN counts, but within the other classes of beans there were no differences across varieties. SCN-inoculated bean seedlings (one variety each of pinto, white and kidney) were also assessed in field conditions and taken to yield. Up to 56% reduction in seed weight of SCN treated pinto beans was observed compared to non-inoculated controls, and up to 37% and 31% for the white and kidney beans, respectively, although losses were not recorded at all locations.Source : Field Crop News