Comparison of Propiconazole Rates for Control of Fungal Brown Spot of Wild Rice. J. A. Percich, Associate Professor, Department of Plant Pathology, University of Minnesota, St. Paul 55108. . Plant Dis. 73:588-589. Accepted for publication 7 February 1989. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/PD-73-0588.

Wild rice (Zizania palustris ‘K-2’) was inoculated with conidial suspensions of Bipolaris oryzae. Propiconazole was applied at 124, 186, and 247 g a.i./ha at boot and heading and 247 and 308 g a.i./ha at boot only. Plants treated with 124 g a.i./ha twice or 308 g a.i./ha once did not have significant (P = 0.05) yield increases or decreased disease severity when compared with the nontreated control. Plants treated with either 186 or 247 g a.i./ha at boot and heading had average significant yield increases of 54 and 87%, respectively. Only one application of propiconazole at 247 g a.i./ha resulted in a significant yield increase of 61% above the control. With the exception of the treatments at 124 and 308 g a.i./ha (phytotoxic), propiconazole reduced leaf infection by 80, 89, and 80% on the flag, F-1, and F-2 topmost leaves, respectively, when compared with the control.