Evaluation of Spray System and Spray Solution Volume for Improved Control of Fusarium Head Blight, 2002.  

S. Halley, Langdon Research Extension Center-North Dakota State University, Box 310 Hwy 5 E Langdon, North Dakota 58249

*Corresponding author PH: (701) 256-2582, E-mail: shalley@ndsuext.nodak.edu  

Objective  

A research trial was conducted in 2002 to compare spraying systems and spray solution volume (GPA) with the fungicide (AMS 21619) for control of Fusarium head blight (FHB) in barley. A 3 x 3 factorial arrangement in a randomized complete block design replicated six times compared a conventional type spray system equipped with hydraulic cone HC6 nozzles oriented down, a conventional type sprayer equipped with hydraulic XR 8001 flat fan nozzles angled downward 30 degrees from horizontal and oriented forward and backward, and a SprayAir� sprayer; an air-assisted spray distribution system angled 30 degrees downward from horizontal and modified by orienting the orifices to spray forward and backward at three GPA, 5.2, 10.4, and 19.2.  

MATERIALS AND METHODS  

The barley cultivar Robust was planted in a field at the Langdon Research Extension Center. An area was planted with a Melroe double-disk grain drill, disks spaced 6-inches apart. The area was divided to plots 12 ft. wide by 20 ft. long. Recommended production practices for Northeast North Dakota were followed. Three weeks prior to heading a Fusarium spawn grown on spring wheat was hand broadcast at a rate of approximately 200 grams/plot.  

The spray solution carrier was CO₂. Nozzle pressure for the conventional spray systems was 40 psi. Orifice spacing was 10 inches for cone and air assisted system and 20 inches for hydraulic nozzles system. GPA was adjusted with tractor speed. The tractor traveled on the left half of the plot area. This area also provided border to reduce off target drift between treatment areas. Visual estimation of FHB incidence and field severity (spikelet count per individual head multiplied times FHB infected spikes per head), 20 samples per plot, were determined 20 days after fungicide application. Each plot was harvested with a Hege plot combine and the grain sample cleaned and processed for yield, test weight, and plump measurement. Data was analyzed with the general linear model (GLM) in SAS. Linear contrasts were used to compare means.  

The spring plant period was wet and the earliest date the site was suitable for planting was 5 May. Fungicide application was made on 1 July at 1:00 p.m.  June average temperature was 2 �F above normal with precipitation at 6.37 inches, 3.2 inches above normal. Mean July temperature was over two �F above normal and precipitation nearly two inches below 30 year normal of 2.9 inches. Greatest rainfall event of the month was 0.36 inches on 5 July.

 

RESULTS AND DISCUSSION  

Spray volume of 5.2 GPA had greater incidence of FHB than spray volume of 19.2 GPA. The conventional nozzle sprayer had smaller levels of FHB field severity than the cone or Spray Air sprayers. The conventional sprayer had greater yield than the cone type nozzle sprayer.  

Sprayer	Gallonage	FHB		Yield	Test	Plump
Orientation		Incidence	Severity		Weight
	/ acre	%	%	bu/ac	lb/bu	%
Cone	5.2	78.6	15.7	76.8	46.0	89.9
Down	10.4	85.0	12.2	75.6	46.6	84.6
	19.2	80.0	15.0	76.4	46.3	90.1
Conventional	5.2	76.7	10.3	78.4	46.5	91.1
F + B	10.4	72.8	11.2	77.2	45.7	92.0
	19.2	69.2	8.9	82.5	46.3	93.3
Spray Air	5.2	85.0	14.0	75.6	45.6	89.3
F + B	10.4	84.6	15.4	78.0	45.9	90.7
	19.2	72.6	8.6	81.0	46.3	90.2
Untreated		72.5	16.1	77.9	45.2	90.4
	5.2	80.1	13.4	76.9	46.0	90.1
	10.4	80.8	13.0	76.9	46.0	89.1
	19.2	73.9	10.8	80.0	46.3	91.2
Cone		81.2	14.3	76.3	46.3	88.2
Conventional		72.9	10.1	79.3	46.2	92.1
Spray Air		80.7	12.7	78.2	45.9	90.1
Untreated vs Rest		NS	NS	NS	NS	NS
5.2 vs 19.2 GPA		*	NS	NS	NS	NS
5.2 vs 10.4 GPA		NS	NS	NS	NS	NS
10.4 vs 19.2 GPA		*	NS	NS	NS	**
Conv. vs Cone		NS	*	*	NS	NS
Conv. vs Spray Air		NS	***	NS	**	*
Cone vs Spray Air		NS	NS	NS	*	NS
% C.V.		17	41	7	2	5

*, **, ***  Significant at 0.1, 0.05, and 0.01 probability level for mean comparisons, respectively.