2007 U of M Research Special Report

On-Farm Disease Management Trials of Spring Wheat in the Red River Valley

During 2006, data were collected from two on-farm locations located near Oklee and Foxhome, MN (cooperators: Ray & Barbara Swenson and Dave & Matt Hasbargen).  Small plots of spring wheat varieties were planted during April into soybean residues. Twelve wheat varieties (Ada, Alsen, Banton, Bigg Red, Briggs, Freyr, Glenn, Knudson, Oklee, SteeleND, Ulen and Walworth) were tested to determine if yield and quality responses from six disease management strategies would complement or compete with disease resistance levels in each variety. For example, if a variety had little resistance against a disease, application of fungicide to protect its yield potential would be logical.  For a variety with greater resistance, an application of fungicide may or may not provide protection over-and-above the level that the variety’s disease resistance would accomplish anyway. We calculated economic analyses for each variety/disease treatment combination from representative grain samples that were graded by Mid-Valley Grain Cooperative in Crookston. For reporting purposes, fictitious grain sales were made based on samples to determine the estimated revenue from each variety/disease management treatment combination.  The sales occurred in mid-November. Deoxynivalenol (DON or vom) levels were non detectable or well below the allowable limit of 2 ppm so discounts did not apply.

Varieties
The drier growing season resulted in few production issues related to disease, however having little disease development is unusual in the Valley.  The Oklee location suffered from drought conditions with powdery mildew and leaf rust developing on susceptible varieties late in the season. The Foxhome location experienced more timely rains, but overall low levels of leaf and stripe rust, Septoria leaf blotch, powdery mildew, and leaf streak mosaic were noted at this location. Moderate bacterial leaf stripe disease pressure was noted at Foxhome. Bacterial leaf stripe is caused by a bacterial disease and leaf streak mosaic is caused by a virus, so neither are controlled by fungicide application. Seven different varieties, (Steele ND, Ulen, Briggs, Walworth, Ada, Oklee, Knudson) represented the top 10 estimated revenue returns (Table 1). There were significant differences between varieties at locations but not between management treatments.  When averaged across both test sites, two disease management treatments resulted in greater estimated returns (Table 1). An application of Headline at the 4-5 leaf stage followed by Folicur at early flower increased estimated revenues above the $300/a level for six of the varieties tested, likewise a solitary fungicide application in the form of a seed treatment (without later foliar or head fungicide applications) resulted in similar returns for a comparable number of varieties. However, these treatments were not statistically better than other treatments tested.  A varietal trend in the data showed increased revenue from a seed treatment compared to the corresponding varietal non treated control treatment.

Disease Management Treatments
When dollars returned per acre is considered exclusively, treatment results varied widely across varieties.  Economically speaking varieties known for having good disease resistance packages, such as Glenn and Alsen, did not offer any needed benefits in the absence of disease. Several management strategies on these two varieties were ranked lowest in estimated revenue (Table 1). Protein premiums for most varieties ranged from $0.01 to $0.06/bushel while some discounts were assigned for reduced protein.

Table 1. One-year data ranking variety and treatment combinations based on dollars/A revenue returned (1=best rank, 72=lowest rank).

Rank	Variety	Trtmt1	Protein	Test Wt	Yield	Prem vs Disc2	Cash Price	Gross $/ac	Fung. Appl. Cost $/ac	Estimated Return
1	Steele ND	SD	14.2	61.6	70.4	0.01	$4.67	$328.77	$3.84	$324.93
2	Ulen	SD	14.5	61.6	70.0	0.02	$4.68	$327.60	$3.84	$323.76
3	Briggs	SD	14.8	61.5	69.1	0.04	$4.70	$324.77	$3.84	$320.93
4	Steele ND	H-F	14.2	61.0	72.0	0.01	$4.67	$336.01	$17.08	$318.93
5	Walworth	SD	14.5	59.8	68.6	0.02	$4.68	$321.05	$3.84	$317.21
6	Ada	H-F	14.4	62.3	70.5	0.02	$4.68	$329.94	$17.08	$312.86
7	Oklee	H-F	14.6	61.8	69.6	0.03	$4.69	$326.42	$17.08	$309.34
8	Knudson	SD	14.4	61.1	66.6	0.02	$4.68	$311.45	$3.84	$307.61
9	Walworth	NONE	14.4	59.5	65.5	0.02	$4.68	$306.54	$0.00	$306.54
10	Briggs	H-F	14.3	61.7	69.2	0.01	$4.67	$323.16	$17.08	$306.08
11	Walworth	H-F	14.6	59.3	68.8	0.03	$4.69	$322.67	$17.08	$305.59
12	Ulen	SD-F	14.8	61.5	68.2	0.04	$4.70	$320.54	$16.03	$304.51
13	Walworth	SD-F	14.2	60.0	67.7	0.04	$4.70	$317.96	$16.03	$301.93
14	Oklee	SD	15.1	61.4	64.8	0.05	$4.71	$305.21	$3.84	$301.37
15	Knudson	H-F	14.5	61.3	68.0	0.02	$4.68	$318.01	$17.08	$300.93
16	Ulen	H-F	14.6	60.5	67.4	0.03	$4.69	$316.11	$17.08	$299.03
17	Walworth	F	14.7	59.0	66.4	0.03	$4.69	$311.18	$12.19	$298.99
18	Steele ND	NONE	14.5	60.2	63.8	0.02	$4.68	$298.58	$0.00	$298.58
19	Knudson	NONE	14.4	61.3	63.6	0.02	$4.68	$297.41	$0.00	$297.41
20	Banton	SD	14.5	63.0	64.4	0.02	$4.68	$301.16	$3.84	$297.32
21	Steele ND	F	14.7	60.4	65.9	0.03	$4.69	$309.07	$12.19	$296.88
22	Briggs	NONE	14.7	60.8	63.2	0.03	$4.69	$296.41	$0.00	$296.41
23	Steele ND	SD-H-F	14.4	60.7	67.7	0.02	$4.68	$316.84	$20.92	$295.92
24	Bigg Red	H-F	13.7	62.9	67.7	-0.04	$4.62	$312.77	$17.08	$295.69
25	Knudson	F	14.4	61.5	65.6	0.02	$4.68	$306.77	$12.19	$294.58
26	Freyr	H-F	14.2	61.1	66.7	0.01	$4.67	$311.26	$17.08	$294.18
27	Bigg Red	SD-H-F	14.4	62.6	67.2	0.02	$4.68	$314.50	$20.92	$293.58
28	Ulen	F	14.8	60.7	65.0	0.04	$4.70	$305.27	$12.19	$293.08
29	Banton	H-F	14.4	62.9	66.2	0.02	$4.68	$309.58	$17.08	$292.50
30	Briggs	F	14.5	61.6	65.0	0.02	$4.68	$303.97	$12.19	$291.78
31	Bigg Red	SD	13.8	62.7	63.7	-0.02	$4.64	$295.57	$3.84	$291.73
32	Ada	SD-F	14.5	62.0	65.7	0.02