�Munich� Durum Response to Adjuvant Rate in 5.2, 10.4, and 19.2 GPA Spray Volume with Folicur Fungicide
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: firstname.lastname@example.org
To determine if efficacy of fungicide, Folicur (Bayer), can be enhanced by differing rates of adjuvant (Induce) at 5.2, 10.4, or 19.2 gpa spray volume to �Munich� durum.
Adjuvants often are recommended added to fungicides for improved consistency under different environmental conditions. Most adjuvants are recommended in tank mixes based on a volume for volume basis (v/v) e.g. one pint adjuvant for each 100 gallons spray solution. An adjuvant (rate recommendation of 0.125 % v/v results in application of 0.125 gallons/100 gallons spray solution or a pint/100 gal. If the solution is applied at 5 gpa the per acre rate would be 1/20 pint. However, when growers increase gpa to 20 the adjuvant rate applied per acre is reduced by �.
This study was initiated to determine if an adjuvant rate by v/v recommendation should be changed when greater water volumes for fungicide application are used.
MATERIALS AND METHODS
�Munich� durum was planted for Folicur fungicide evaluation (4 oz/acre rate) 4 May with a Melroe double disk drill, disks spaced 6-inches apart, in a field at the Langdon Research Extension Center in spring 2002. The area was divided to plots 12 ft. wide by 20 ft. long in a RCB design with six replicates arranged as an Adjuvant Rate x GPA factorial. 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.
Adjuvant rates were:
2. 142 ml v/v (7.4 ml/acre at 19.2 gpa to 27ml/acre at 5.2 gpa)
3. 472.5 ml v/v (24.6 ml/acre at 19.2 gpa to 90.9ml/acre at 5.2 gpa)
1 pint = 472.5 ml
Treatments were applied by a modified SPRAYAIR� tractor sprayer. The sprayer was modified to distribute the solution from orifices angled 30 degrees downward from horizontal oriented forward and backward to maximize spike coverage. The solution carrier was CO2 delivering volumes of 5.2, 10.4, and 19.2 gpa into the air stream. 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 FHB incidence and field severity, 20 samples per plot, (spikelet count per individual head multiplied times FHB infected spikes per head) 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 and test weight measurement. Data was analyzed with the general linear model (GLM) in SAS. Least significant differences (LSD) were used to compare means at the 5% probability level.
RESULTS AND DISCUSSION
Adjuvant rate did not affect any parameters. Increasing gallonage decreased the FHB field severity. Gallonage application at 10.4 negatively affected test weight. Strong negative correlations were determined between FHB incidence and field severity and test weight. A moderate negative correlation between FHB field severity and yield were measured indicating that reduction in FHB parameter explains a considerable portion of test weight or yield increase.
* Significant at 0.05 probability level for mean comparisons.
** Significant at 0.1 probability level for mean comparisons
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