Evaluation of fungicides for control of brown spot of soybean in Wisconsin, 2014

摘要

The trial was established at the Arlington Agricultural Research Station located in Arlington, WI. The soybean cultivar '92Y51' was chosen for this study. Soybeans were planted on 21 May 2014 in a field with a Joy silt loam soil (2 to 4 percent slopes). The experimental design was a randomized complete block with four replicates. Plots consisted of four 30-in. spaced rows, 20 ft long and 10 ft wide with 5-ft alleys between plots. Standard soybean production practices as described by the University ofWisconsin Cooperative Extension Service were followed. Treatments consisted of a non-treated control and 20 fungicide and/or insecticide treatments. Pesticides were applied using a CO2-pressurized backpack sprayer equipped with 8001 TurboJet flat fan nozzles, spaced 15 in. apart, and calibrated to deliver 20 gal/A at 28 PSI. Pesticides were applied at growth stages R1 (7 Jul), R3 (21 Jul), both R1 and R3, or R3 and R4 (5 Aug). Natural sources of pathogen inoculum were relied upon for disease. Disease was evaluated at growth stage R6 by visually assessing leaf disease severity using a standardized area diagram. Yield was determined by harvesting the center 2 rows of each plot using a small-plot combine. All disease and yield data were analyzed using amixed model analysis of variance and means were separated using Fisher's least significant difference (a=0.05).