Evaluating fungicides for managing tan spot on hard red spring wheat in Minnesota, 2008.

摘要

On 1 May, hard red spring wheat was planted with a Hege plot drill at 1.35 million live seed/A into Wheatville loam soil having soybean residue present. The trial was arranged in a randomized complete block design with four replicates. Each plot was 5ft x 25 ft with rows 6 in. apart. An application of Axial (0.66 pt/A) and Bronate Advanced (1.0 pt/A) was made 17 Jun to manage weeds. On 17 Jun (tillering growth stage, F2) or 26 Jun (flag leaf emergence, F9) fungicide treatments were applied using a backpack-type sprayer with XR Teejet flat fan 8002VS nozzles spaced 20 in. apart on a 5-ft boom at 20 gpa and 40 psi. On 25 Jul, whole plots were rated for leaf disease prevalence using a scale from 0 to 5 where 0 = no disease and 5 = 91-100% leaves diseased. On 28 Jul, 50 wheat spikes/plot were rated for Fusarium head blight (FHB) incidence (percent of heads with symptoms) and severity (percent of symptomatic spikelets on diseased heads). Plots wereharvested 21 Aug, and grain was cleaned using a Clipper Eclipse seed sizer and conditioner. Grain subsamples of approx. 1.8 oz/plot were sent to the Univ. of Minnesota Mycotoxin Lab in St. Paul to determine deoxynivalenol (DON) content. Results were analyzed using PROC GLM in SAS, with Fisher’s Protected Least Significant Difference (LSD) mean separations atP=0.05.