Kaitany, R., H. Melakeberhan, G. W. Bird, and G. Safir. 2000. Association of Phytophthora sojae with Heterodera glycines and nutrient stressed soybeans. Nemtropica 30:193-199. Soybean cyst nematode (SCN, Heterodera glycines ), a serious pest of soybeans, has been found in 30 counties in Michigan. Phytophthora sojae , a serious and opportunistic pathogen of soybeans, has also been found in many of the fields. This study was conducted to assess the incidence of P. sojae in 12 selected soybean cultivars grown under low (fumigated) and high (non-fumigated) SCN conditions and nutrient stress. A total of 70 soil and root and stem samples (same plant) from each nematicide treatment were analyzed for SCN population densities and P. sojae. Incidence of P. sojae was highly correlated with SCN population densities in untreated plots; whereas, both organisms were low in the treated plots and poorly correlated. Leaf N and K were significantly higher in nematicide-treated plots while the reverse w
