Hard red spring wheat cultivars were planted during the first week of May at four locations in ND. Oxen spring wheat was planted at the Fargo Experiment Station, Grandin was planted at the Langdon and Minot Research Extension Centers, and Russ was planted at the Carrington Research Extension Center. Previous crop history, soil types and plot size varied per site, with wheat planted into wheat residue at Fargo, into soybean ground at Carrington, and into canola ground at Minot and Langdon. Plots were replicated 4 times at each site. At Fargo and Langdon, plots were inoculated by broadcasting Fusarium graminearum colonized corn and barley kernels (100g/plot) over the plot surfaces two weeks prior to the flowering stage (Feekes' 10.51). At Carrington, infested wheat straw was distributed across plots soon after planting. Inoculum was from natural sources at Minot. Plots were mist irrigated at Fargo and Langdon, overhead irrigated at Carrington, and dryland at Minot. The biological agent OH 182.9 and fungicide treatments were applied as sprays at 18 gpa with a CO2-pressurized back pack sprayer with a constant boom pressure of 40 psi and 20 in. spacing between XR8001 flat fan nozzles mounted forward and backward at a 30 degree angle from the horizontal. Sprays were applied at early flowering, corresponding to Feekes' growth stage 10.51. Plots were assessed for % flag leaf infection of fungal leaf spots and for the presence of Fusarium head blight (FHB) at soft dough stage of kernel development (Feekes' growth stage 11.2). Incidence of FHB was determined by counting heads with symptoms per 30 heads/plot, and head severity was determined as average % symptomatic florets per head. FHB field severity was determined by multiplying incidence x head severity. Rainfall at Fargo was below normal from 15 May to 15 Jul, totaling 4.0 in., while rainfall for the same time period at Langdon, Minot, and Carrington totaled 6.3 in., 5.0 in., and 8.0 in., respectively. During the flowering period of 28 Jun to 15 Jul, temperatures averaged 83oF at Fargo and 78oF at the other three sites. Plots were harvested in early Aug at all sites with plot combines. Yield (bu/A) was determined from harvested grain adjusted to 13.5% moisture and cleaned once with a Clipper mill. Harvested grain was analyzed for DON content at the North Dakota State University Toxicology lab using gas chromatography with electron capture detection. Data were analyzed across sites using mean values from each location as replicates.

All treatments significantly reduced the FHB field severity from the untreated control, and all fungicide treatments had significantly lower FHB field severity values than the biological agent. Fungal leaf spots were significantly reduced by all fungicide treatments, but not by the biological agent. Yields and test weights were significantly improved by all fungicide treatments, but not by the biological agent. FHB and leaf disease levels were highest at Langdon and Carrington, the two sites having the greatest precipitation during flowering and early grain fill periods.