長尾, 英幸

NAGAO, Hideyuki

Pod yellowing of soybean occurred in Higashi-katsushika district of Chiba prefecture and its pathogen were studied. Downy mildew of soybean invaded from stroma of the pod, and its hyphae extended through the parenchyma and the endocarp. Then oospores were produced there. Staining with lacophenol aniline blue, hyphal growth and formation of the characteristic haustoria in the cells were observed by light microscope. In the field survey, pods borne at the third and the fourth nods were severely infected but there were no relation between the number of pods and the number of infected ones. Epidemiology of this disease was not known. As the economic loss by this disease in this region got to be very serious, susceptibility of cultivar to downy mildew and race differentiation of this pathogen should be examined.