Seasonal occurrence of P. penetrans, H.glycines and P gregata f.sp. adzukicola, causal agent of brown stem rot of adzuki bean (BSR), and the damage of adzuki bean as postcrop was determined in a field in Shihoro, Hokkaido where several green manure crops were cultivated in the previous year. The results obtained from the plot planted with wild oats showed that population densities of P. penetrans and P. gregata f.sp. adzukicola in soil remained low, and infection and damage degree of post-crop adzuki bean by BSR was so low that a high yield was obtained. By contrast, in the sweet corn plot, the density of P. penetrans was very high and P. gregata f.sp adzukicola was somewhat high, and the damage of adzuki bean by BSR was so severe that a low yield was obtained. The densities of H glycines was decreased to zero at all green manure crops except adzuki bean. Jpn. J. Nematol. 35(2), 79-86 (2005).