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

During 2007, data were collected from two on-farm locations located near Oklee and Fergus Falls, MN (grower cooperators: Ray & Barbara Swenson and Tom & Deb Jennen). Small plots of spring wheat, replicated four times, were planted into sites with soybean residue. Thirteen wheat varieties (Ada, Alsen, Banton, Bigg Red, Briggs, Freyr, Glenn, Knudson, Oklee, Samson, Steele-ND, Ulen, and Walworth) were tested to determine if yield and quality responses from six disease management strategies would be profitable for each variety.  We calculated economic analyses for each variety/disease treatment combination from representative grain samples that were graded. For reporting purposes, fictitious grain sales were made based on harvest results to determine the estimated revenue generated by 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.

Wheat fields that had epidemics of tan spot were few and far between this year.  Leaf rust arrived in the Valley and was established before the crop headed in some locations, but disease development stalled on most varieties until the grain filling stages when it became severe.  Prevalence of Fusarium head blight was generally low across the Valley, but a few localized epidemics were reported. Weather conditions varied substantially between test locations near Oklee and Fergus Falls.  The test at Fergus Falls had statistically lower grain test weights, kernel protein, and FHB disease than the test at Oklee. No other data were significantly different due to the location effect. Deoxynivalenol (DON, vom, vomitoxin) levels in grain, caused by Fusarium graminearum infection, were low at both test sites.

Varieties
Variety and disease management strategy had significant effects on yield, test weight, protein, FHB incidence, FHB severity, FHB index, and net revenue returned (P<0.05).  When averaged over both locations, Samson, Ulen, Steele-ND, and Oklee had the most severe FHB symptoms, while Bigg Red, Alsen, Glenn, and Knudson had the least. Since FHB wasn’t a limiting factor for production this year, varieties known for their susceptibility to the disease had excellent yields; Knudson (77.8 bu/A), Samson (77.6 bu/A), and Steele-ND (74.9 bu/A).  Those with FHB resistance had lower yields; Bigg Red (62.4 bu/A) and Alsen (63.3 bu/A). When averaged across all fungicide treatments, Knudson ($611.27/A), Samson ($608.26/A), and Steele-ND ($591.48/A) brought in the largest net returns, while Bigg Red ($482.89/A) and Alsen ($497.13/A) had the smallest (P<0.05). 

Disease Management Treatments
Yield, protein, and test weights were significantly increased with disease management strategies #3, #4, and #5, compared with the nontreated control, strategy #1 (Table 1). Disease management strategy #4 (seed treatment and foliar and early-flowering applications) resulted in the largest net returns when averaged across all varieties (P<0.05).  Establishing a good stand and then using follow-up fungicides to protect crop productivity at key intervals resulted in the greatest return of the strategies tested. Fungicide seed treatment increased estimated net revenue for about half the number of the varieties. While not statistically significant, net revenues resulting from the fungicide seed treatment were greater than the nontreated control for Freyr (2%), Steele-ND (3%), Knudson (3%), Glenn (3%), Alsen (4%), and Samson (8%).

Overview
Wheat varieties responded well to this year’s growing environment, producing excellent yields of high quality grain.  However, fungicide application increased net returns compared with the no fungicide treatment for many varieties even during a year of relatively low disease pressure.  Economically-speaking, those producers benefitting the most during 2007 grew FHB susceptible varieties, but those who slept the best during the growing season grew more resistant varieties.

This project was funded by the Minnesota Wheat Research and Promotion Council, the U.S. Wheat and Barley Scab Initiative, and WestBred LLC.  The project was supported by BASF Corp., Bayer CropScience, Syngenta, AgriPro Wheat, Trigen Seed, and the University of Minnesota Mycotoxin lab. This research represents single year information.  Environmental conditions and disease pressures can vary substantially from year to year. This material is based upon work supported by the U.S. Department of Agriculture, under Agreement No. 59-0790-3-080.  This is a cooperative project with the U.S. Wheat & Barley Scab Initiative. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the view of the U.S. Department of Agriculture.

Table 1. Disease management strategies tested during 2007 at two test locations in the Red River Valley.

		Application
Strategy	Product	Rate*	Timing
1	Nontreated control	--	--
2	Dividend Extreme	3 fl. oz./100 lbs.	seed applied
3	Headline	3 fl. oz./a	4-5 leaf
	Folicur/Proline	3 + 3 fl. oz./a	early flower
4	Dividend Extreme	3 fl. oz./100 lbs.	seed applied
	Headline	3 fl. oz./a	4-5 leaf
	Folicur/Proline	3 + 3 fl. oz./a	early flower
5	Dividend Extreme	3 fl. oz./100 lbs.	seed applied
	Folicur/Proline	3 + 3 fl. oz./a	early flower
6	Folicur/Proline	3 + 3 fl. oz./a	early flower
*Treatments 3 through 6 included 0.125% Induce, a nonionic surfactant.

Table 2. 2007 Red River on-farm disease management trial results.

	Fungicide	Protein	Test Wt.	Yield	Premium/	Cash	Fung. Appl.	Estimated
Variety	Timing	(%)	(lb/bu)	(bu/a)	Discount2	Price	cost $/a3	Return |($/a)
Ada	S, L, F	14.3	62.9	80.7	$-0.02	$8.06	$26.51	$623.49
	F	14.2	62.1	75.8	$-0.03	$8.05	$17.40	$592.52
	S, F	14.2	62.3	76.0	$-0.04	$8.04	$21.38	$590.10
	S	13.8	62.2	70.2	$-0.06	$8.02	$3.98	$558.58
	L, F	14.4	62.6	71.2	$-0.03	$8.05	$22.53	$551.45
	None	13.6	62.6	66.7	$-0.10	$7.98	$0.00	$533.38
	Mean	14.1	62.5	73.4	$-0.05	$8.03	$15.30	$574.92
Alsen	F	14.6	61.6	65.6	$0.01	$8.09	$17.40	$513.75
	L, F	14.6	61.9	65.8	$0.01	$8.09	$22.53	$510.09
	S, L, F	14.8	61.4	64.6	$0.02	$8.10	$26.51	$497.36
	S	14.8	61.4	61.7	$0.03	$8.11	$3.98	$495.81
	S, F	14.6	61.7	63.2	$0.02	$8.10	$21.38	$490.39
	None	14.4	61.5	58.8	$0.00	$8.08		$475.37
	Mean	14.6	61.6	63.3	$0.02	$8.10	$15.30	$497.13
Banton	L, F	14.6	62.7	77.5	$0.02	$8.10	$22.53	$604.81
	S, F	14.6	62.8	73.7	$0.02	$8.10	$21.38	$575.67
	S, L, F	14.6	62.6	73.3	$0.02	$8.10	$26.51	$566.75
	None	14.4	62.7	69.8	$0.00	$8.08	$0.00	$564.16
	S	14.5	62.5	70.0	$0.00	$8.08	$3.98	$561.86
	F	14.4	62.8	69.5	$0.00	$8.08	$17.40	$544.14
	Mean	14.5	62.7	72.3	$0.01	$8.09	$15.30	$569.57

Bigg Red	S, L, F	14.2	62.6	70.5	$-0.01	$8.07	$26.51	$542.24
	L, F	13.8	62.7	67.7	$-0.08	$8.00	$22.53	$519.17
	F	14.0	63.2	64.9	$-0.03	$8.05	$17.40	$504.77
	S, F	13.7	63.1	63.6	$-0.07	$8.01	$21.38	$488.33
	None	12.5	62.2	55.3	$-0.24	$7.84	$0.00	$433.79
	S	12.7	62.5	54.4	$-0.21	$7.87	$3.98	$424.44
	Mean	13.5	62.7	62.7	$-0.11	$7.97	$15.30	$485.46
Briggs	S, L, F	15.0	61.7	75.4	$0.03	$8.11	$26.51	$584.81
	None	14.8	61.2	70.8	$0.02	$8.10	$0.00	$573.90
	S	15.0	61.3	71.2	$0.02	$8.10	$3.98	$572.84
	L, F	14.8	61.9	73.4	$0.01	$8.09	$22.53	$570.65
	S, F	14.5	61.5	69.1	$-0.02	$8.06	$21.38	$535.79
	F	14.9	61.6	67.6	$0.03	$8.11	$17.40	$530.55
	Mean	14.8	61.5	71.3	$0.02	$8.10	$15.30	$561.42
Freyr	L, F	14.5	61.1	76.3	$0.02	$8.10	$22.53	$595.53
	S, L, F	14.1	61.5	76.6	$-0.03	$8.05	$26.51	$590.85
	S	14.1	61.3	71.8	$-0.03	$8.05	$3.98	$574.38
	F	14.1	61.0	72.2	$-0.02	$8.06	$17.40	$564.22
	None	13.8	60.5	70.0	$-0.06	$8.02	$0.00	$562.19
	S, F	14.4	61.1	70.3	$0.00	$8.08	$21.38	$546.29
	Mean	14.2	61.1	72.9	$-0.02	$8.06	$15.30	$572.24
Glenn	S, L, F	15.0	62.3	73.5	$0.04	$8.12	$26.51	$570.24
	S	15.3	62.3	67.4	$0.06	$8.14	$3.98	$544.14
	None	15.0	61.8	65.0	$0.04	$8.12	$0.00	$528.64
	F	14.8	62.5	67.4	$0.02	$8.10	$17.40	$528.04
	S, F	14.9	62.2	67.2	$0.03	$8.11	$21.38	$524.28
	L, F	15.1	62.3	67.1	$0.05	$8.13	$22.53	$523.08
	Mean	15.0	62.2	67.9	$0.04	$8.12	$15.30	$536.40
Knudson	S, L, F	14.0	62.1	82.1	$-0.03	$8.05	$26.51	$634.76
	S	13.9	62.2	78.8	$-0.05	$8.03	$3.98	$629.36
	F	14.2	61.5	79.1	$0.00	$8.08	$17.40	$621.30
	None	13.7	61.9	76.5	$-0.07	$8.01	$0.00	$612.86
	L, F	14.2	61.7	77.1	$-0.01	$8.07	$22.53	$599.10
	S, F	14.0	61.7	73.5	$-0.04	$8.04	$21.38	$570.22
	Mean	14.0	61.9	77.9	$-0.03	$8.05	$15.30	$611.27
Oklee	S, L, F	14.8	62.4	72.9	$0.02	$8.10	$26.51	$564.09
	L, F	14.8	61.9	70.5	$0.01	$8.09	$22.53	$547.97
	None	14.6	62.6	67.0	$0.01	$8.09	$0.00	$542.63
	S	14.9	62.6	67.1	$0.03	$8.11	$3.98	$539.55
	S, F	14.8	62.9	66.7	$0.00	$8.08	$21.38	$518.01
	F	15.3	62.1	65.6	$0.06	$8.14	$17.40	$516.42
	Mean	14.9	62.4	68.3	$0.02	$8.10	$15.30	$538.11

Samson	F	14.0	61.7	81.6	$-0.05	$8.03	$17.40	$638.45
	S, L, F	14.2	62.0	81.5	$-0.02	$8.06	$26.51	$630.84
	S	13.6	61.4	78.5	$-0.08	$8.00	$3.98	$624.57
	L, F	14.0	61.8	77.9	$-0.05	$8.03	$22.53	$604.36
	S, F	13.9	61.5	74.9	$-0.05	$8.03	$21.38	$579.87
	None	13.4	61.3	71.5	$-0.11	$7.97	$0.00	$571.50
	Mean	13.9	61.6	77.7	$-0.06	$8.02	$15.30	$608.27
Steele-ND	S, L, F	14.6	62.5	79.6	$0.00	$8.08	$26.51	$617.04
	S	14.9	62.4	75.2	$0.03	$8.11	$3.98	$605.91
	F	14.5	61.7	75.6	$0.00	$8.08	$17.40	$593.70
	None	14.6	62.2	72.8	$0.01	$8.09	$0.00	$589.10
	S, F	14.6	62.2	74.4	$0.02	$8.10	$21.38	$580.97
	L, F	14.7	62.7	77.1	$0.02	$8.10	$22.53	$562.15
	Mean	14.7	62.3	75.8	$0.01	$8.09	$15.30	$591.48
Ulen	S, L, F	14.9	61.9	74.3	$0.04	$8.12	$26.51	$576.51
	F	14.7	61.9	73.0	$0.01	$8.09	$17.40	$573.88
	S, F	14.3	62.1	73.0	$-0.01	$8.07	$21.38	$568.01
	L, F	14.7	61.8	71.9	$0.01	$8.09	$22.53	$559.61
	None	14.4	61.8	68.6	$-0.01	$8.07	$0.00	$554.34
	S	14.4	61.5	67.7	$-0.01	$8.07	$3.98	$542.23
	Mean	14.6	61.8	71.4	$-0.01	$8.07	$15.30	$562.43
Walworth	L, F	14.7	61.2	75.5	$0.01	$8.09	$22.53	$588.58
	S, L, F	14.4	61.0	74.4	$-0.02	$8.06	$26.51	$573.39
	F	14.6	60.8	68.6	$0.01	$8.09	$17.40	$537.53
	S	14.1	61.0	67.3	$-0.04	$8.04	$3.98	$536.97
	None	14.2	61.1	66.0	$-0.02	$8.06	$0.00	$531.92
	S, F	14.5	61.1	67.2	$-0.01	$8.07	$21.38	$521.13
	Mean	14.4	61.0	69.8	$-0.01	$8.07	$15.30	$548.25
GRAND MEAN		14.4	61.9	71.1	$-0.01	$8.07 $15.30	$15.30	$558.23
1Fungicide treatment product, rate and timing:  None= No fungicide treatment; S= Dividend Extreme, 3 oz/100 lbs as a seed treatment; F= Folicur and Proline 3 fl oz each/a at early flower; L, F= Headline, 3 fl oz/a at the 4-5 leaf stage and tank mix of Folicur and Proline 3 fl oz each/a at early flower; S, F= Dividend Extreme, 3 oz/100 lbs as a seed treatment and tank mix of Folicur and Proline 3 fl oz each/a at early flower;  S, L, F= Dividend Extreme, 3 oz/100 lbs as a seed treatment followed by Headline, 3 fl oz/a at the 4-5 leaf stage and tank mix of Folicur and Proline 3 fl oz each/a at early flower. NOTE:  Both the Headline treatment and Folicur + Proline (tank-mixed) treatment included 0.125% Induce, a nonionic surfactant. 2On 31 Oct. 2007, analysis started with a cash base price of $8.08/bu. Protein premiums based up 1 per 1/5 and discounts based down 3 per 1/5.  Protein adjustments were averaged across two locations each having four replications. 3Fungicide costs based on Dividend Extreme at $170/gal, Headline at $219/gal, Folicur at $79/gal after rebate, Proline at $450/gal and early flower application cost of $5/a. Fungicide costs translate to Dividend Extreme $3.98/a; Headline $5.13/a; Folicur + Proline $12.40/a. No additional cost for application was added for seed treatment as it was treated at time of drill filling and the 4-5 leaf application would be made in combination with herbicide application.

-- Charla Hollingsworth, Extension Plant Pathologist; Chris Motteberg, Plant Pathology Scientist; Doug Holen, Regional Extension Educator; and Lorilie Atkinson Plant Pathology Scientist.