Effects of Temperature on Development of Heterodera glycines on Glycine max and Phaseolus vulgaris.

Soybean cyst nematode resistant 'Fayette' and susceptible 'Williams 79' soybeans (Glycine max) and resistant 'WIS (RRR) 36' and susceptible 'Eagle' snap beans (Phaseolus vulgaris) were used in determining the effects of host and temperature on the development, female production, sex ratios, and host response to Heterodera glycines. Temperatures were maintained constant at 16, 20, 24, 28, and 32 C using water-filled tanks. The most rapid development and greatest female production occurred between 20 and 28 C. The equation DS = 5(10)x(2)y(2) - 3(10)x(2)y - 2.8(10(3))x(2) - 1.94(10(2))y(2) + 0.4288x + 1.0220y - 12.7185, where DS = developmental stage, X = time, and Y = temperature, predicted the developmental stage of the nematode and accounted for 84% of the variation. Male : female ratios did not differ within this range and were generally less than one. At all temperatures the resistant soybean produced the greatest number of necrotic responses to H. glycines infection, followed by the resistant snap bean. The susceptible soybean and snap bean produced the fewest necrotic responses.