Evaluation of foliar fungicides on corn diseases and yield in southwestern Indiana, 2014

摘要

Plots were established at the Southwest Purdue Agronomy Center (SWPAC) in Knox County. The experiment was a randomized complete block design with four replications. Plots were 10ft wide and 30ft long, and the two center rows were used for evaluation.The previous crop was soybeans. Field tillage, fertilizer, and weed control were managed according to standard practices. Corn hybrid P1343AM1 was planted in 30-in. row spacings at a rate of 32,000 seeds/A on 6 May using a John Deere six row planter. Fungicide applications were applied with a CO2 pressurized backpack sprayer and 5 ft hand-held boom fitted with four TJ-VS 8001 nozzles spaced 20 in. apart, which delivered 15 gal/A at 40 psi. Fungicides were applied on 14 Jul at the VT/R1 growth stage. Disease severity was assessed on 28 Aug at the R5 growth stage. Disease severity was rated by visually assessing the percentage of symptomatic leaf area of the ear leaf on 5 plants per plot. Values for each plot were averaged before analysis. The center 5ftof each plot was harvested with a Kincaid plot combine on 6 Oct. Grain yield, moisture, and test weight were collected and yields were adjusted to 15.5% grain moisture before analysis. Data were subjected to analysis of variance and means were comparedat the 0.05 significance level using Fisher's protected least significant difference (LSD) test.