Effect of Soybean Cyst Nematode on Growth of Dry Bean in the Field.

Phaseolus vulgaris is a host of soybean cyst nematode (SCN; Heterodera glycines), but the effects of SCN on growth of dry bean plants are poorly understood. To study the effects of SCN (HG type 0) on dry bean, the cultivars GTS-900 (pinto bean), Montcalm (kidney bean), and Mayflower (navy bean) were evaluated in eight field experiments at four locations between 2007 and 2009. Plants were grown in a pasteurized Arveson loam soil that was infested with SCN eggs at densities ranging from 0 to 10,000 eggs/100 cm soil. Soil was placed in 14.6-liter plastic pots that were buried in the field with the bottoms removed. SCN reproduced on all three dry bean cultivars with reproduction factors (RF = number of eggs in the soil at harvest divided by number of eggs at planting) ranging from 6.1 to1.2. RFs were higher for dry bean plants growing at lower egg densities compared to higher densities. Pod number (PN), pod weight (PW), seed number (SN), and seed weight (SW) of GTS-900 were significantly less at 5,000 and 10,000 eggs/100 cm soil compared with the control. Averaged over those two egg densities, PN, PW, SN, and SW were reduced by 44 to 56% over the 2 years compared with the control. For Montcalm, significant reductions of 31 to 35% in PW, SN, SW, and total dry weight (TDW) in treatments of 2,500 and 5,000 eggs/100 cm soil were recorded in 2009, but not in 2008. For Mayflower, significant reductions of 27 to 41% in PH, PW, SN, SW, and TDW in treatments of 2,500 and 5,000 eggs/100 cm soil compared with the control were recorded in one out of two experiments in 2009. The reproduction of SCN on roots and the reduction in plant growth and seed yield on three different bean classes under field conditions indicates SCN is a potential threat to the large dry bean industry in the North Dakota-northern Minnesota region.