Effects of Rainfall and Temperature on Production of Perithecia by Gibberella Zeae in Field Debris in Michigan

Gibberella zeae (anamorph Fusarium graminearum) causes scab (blight) in wheat and barley, and ear rot in corn. Since 1991, epidemics of Gibberella head blight have struck the Midwestern states with disastrous effects on wheat and barley growers. The fungus decreases yields and also contaminates grain with trichothecene mycotoxins that are harmful to human and animal health. To understand and control head scab, the factors and conditions that lead to epidemics must be identified. We propose that the sexual spores of Gibberella zeae play a important role in head blight epidemics. We will test this hypothesis by deleting critical genes required for sexual spore development (ascospores) and examine the resulting strains under field conditions for their effect on disease progression on wheat. If ascospores are the major inoculum source, than we predict that exposure of wheat to a MAT-null strain will result in significantly less disease than exposure to a wild-type strain. 2000 National Fusarium Head Blight Forum 129 Epidemiology and Disease Management DEVELOPMENT OF FUSARIUM GRAMINEARUM IN DETACHED SEGMENTS OF BARLEY LEAVES W.R. Bushnell*, R.W. Skadsen, S. Lewandowski, T. Seeland, and D.E. Krueger USDA-ARS, Cereal Disease Laboratory and University of Minnesota, St. Paul, MN, 55108; USDA-ARS, Barley and Malt Laboratory, Madison, WI *Corresponding author: PH: (612) 625-7781, E-mail: [email protected]