Fungicide control of Fusarium head blight and leaf diseases of soft red winter wheat in Kentucky, 2006.

摘要

As part of the multi-state, National 2006 Uniform Fusarium Head Blight (FHB) Fungicide Trials, a test was established on the Kevil Tract of the University of Kentucky Research and Education Center in Princeton, KY. The soft red winter wheat variety Pioneer 25R54 was planted no-till following corn harvest on 12 Oct 05. Wheat was planted at a rate that would achieve a final stand of approximately 36 plants ft~2. The block of wheat was treated with 2.56 fl oz/A Warrior insecticide on 21 Nov and again atgreen-up on 22 Mar 06 to reduce the potential for barley yellow dwarf to be a factor in the test. Liquid nitrogen (45-0-0) was applied at a rate of 40 lb actual N on 15 Feb 06 and 80 lb actual N on 17 Mar 06. Weeds were controlled by applying 0.5 fl oz/A Harmony Extra herbicide on 22 Mar 06. Plots approximately 4 ft-wide x 15 ft-long were established by mowing when plants were entering the stem elongation stage (1 Apr). Fungicide treatments were applied with a hand-held CO_2-powered backpack sprayer equipped with a twin nozzle (twinjet XR8001) configuration (fore- and rear-facing). Treatments were applied in 20 gpa at 40 psi. Treatments were arranged following a randomized complete block with four replications. Plots were rated for FHB and leaf blotchcomplex (primarily tan spot, but also Stagonospora leaf blotch) at the mid-dough stage (Feeke’s stage 11.2) on 24 May 06. Both FHB and leaf blotch complex ratings were made on ten arbitrarily-collected main tillers per plot and were based on visual estimation of percent surface area diseased. Entire plots were harvested on 21 Jun 06 using a Hege 125B small plot combine. Yields were adjusted to 11.7% moisture and 60 lb/bu. Fusarium damaged kernels (FDK) were assessed by counting the number of damaged kernels out of 200 for each treatment plot. Counts were repeated a second time and the average was used for each plot. Deoxynivalenol (DON) analysis was performed on 50-g ground grain samples from each treatment plot. Ground grain samples were analyzed for DON at Michigan State University, East Lansing, MI.