Lack of Economic Benefits by Fungicides Applied Through Center-Pivot Irrigation Systems for Control of Alternaria solani on Potato. G. D. Easton, Plant Pathologist, Department of Plant Pathology, Irrigated Agriculture Research and Extension Center, Washington State University, Prosser 99350. M. E. Nagle, Agricultural Technologist III, Department of Plant Pathology, Irrigated Agriculture Research and Extension Center, Washington State University, Prosser 99350. Plant Dis. 69:152-153. Accepted for publication 3 August 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-152.

In south central Washington, near the Oregon border, fungicides applied through center-pivot irrigation systems were evaluated for 3 yr for control of Alternaria solani on potato. Four applications of fentin hydroxide applied through a center-pivot irrigation system did not control A. solani or increase tuber yield. Four to six applications of chlorothalonil applied through a center-pivot system in August, before the onset of early blight, significantly reduced lesion numbers in all years of testing but did not increase yield.