Efficacy of pre-flag leaf emergence foliar fungicide application for Stagonospora nodorum blotch management in soft red winter wheat
K. T. Willyerd (1), C. Bradley (2), S. Conley (3), P. Esker (3), L. Madden (1), K. Wise (4), P. PAUL (1)
(1) Ohio State University, Wooster, OH, U.S.A.; (2) University of Illinois, Urbana, IL, U.S.A.; (3) University of Wisconsin, Madison, WI, U.S.A.; (4) Purdue University, West Lafayette, IN, U.S.A.
Phytopathology 101:S191

The objective of this study was to evaluate claims that foliar fungicide applications prior to flag leaf emergence provide yield and economic benefits and adequate foliar disease control in soft red winter wheat. Field trials were established in Illinois, Indiana, Ohio and Wisconsin during the 2009/10 season. Two cultivars, one susceptible and one resistant to Stagonospora nodorum blotch (SNB), were planted in a randomized complete block design, with cultivar as whole-plot, fungicide treatment as sub-plot, and inoculation-timing as sub-sub-plot. There were nine foliar fungicide treatments: separate full-rate applications of Headline and Prosaro at Feekes 5, 8, and 10; double half-rate applications of each fungicide at Feekes 5 and 8; and an untreated check. Cultivar was statistically significant (P < 0.05) for SNB severity in IL and OH and for yield in IL. Fungicide treatment had significant effects on SNB severity in IL, IN and WI, significant effects on yield in IL and OH, and marginal significant effect on yield in WI (P = 0.069). The effect of inoculation was not significant for SNB or yield at any location. Overall, the resistant cultivar had lower disease severity and higher yields than the susceptible cultivar. Fungicide applications at Feekes 8 or 10 resulted in lower SNB severity and greater yields than the check. In general, applications at Feekes 5 were not significantly different from the untreated check in terms of SNB severity and yield.