Eight Nonhost Weed Species of Heterodera glycines in Iowa. A. T.S. WONG, Former Graduate Research Assistant, 351 Bessey Hall, Iowa State University, Ames 50011. G. L. TYLKA, Assistant Professor, Department of Plant Pathology, 351 Bessey Hall, Iowa State University, Ames 50011. Plant Dis. 78:365-367. Accepted for publication 23 December 1993. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-0365.

The ability of the soybean cyst nematode (Heterodera glycines) to reproduce on eight weed species commonly occurring in Iowa was evaluated in greenhouse and field microplot experiments. Population densities of the nematode increased on H. glycines-susceptible soybean but not on H. glycines-rtsistanl soybean, Canada thistle, cocklebur, eastern black nightshade, giant foxtail, lambsquarters, redroot pigweed, velvetleaf, and wild sunflower. All of the weeds evaluated were nonhosts of this H. glycines race 3 population.