Effect of Liquid Volume, Spray Pressure, and Nozzle Arrangement on Coverage of Plant Foliage and Control of Snap Bean Rust with Chlorothalonil. F. D. Tompkins, Associate Professor, Department of Agricultural Engineering, University of Tennessee, Knoxville. D. J. Canary, Former Graduate Research Assistant, Department of Agricultural Engineering, University of Tennessee, Knoxville; C. A. Mullins, Associate Professor, Department of Plant and Soil Science, University of Tennessee, Crossville; and J. W. Hilty, Professor, Department of Entomology and Plant Pathology, University of Tennessee, Knoxville 37901-1071. Plant Dis. 67:952-953. Accepted for publication 11 February 1983. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-952.

Chlorothalonil (2.5 kg a.i./ha) solutions were sprayed on snap beans (Phaseolus vulgaris) on a 7- to 10-day schedule to control bean rust (Uromyces appendiculatus var. appendiculatus). Solution application rates were 190, 375, and 560 L/ha at 345 and 690 kPa nozzle pressure, using one, two, and three nozzles per row. Foliage coverage was evaluated using fluorescent tracer particles applied similarly. Mean percentage of surface area covered on both top and bottom sides of the leaves increased with increases in application rate, nozzle pressure, or number of nozzles per row. Rust control, however, was not influenced by these factors. Plots treated with chlorothalonil had less bean rust and produced greater pod yields than untreated plots.

Keyword(s):