When spraying post-emerge herbicides in conventional soybeans, getting good coverage is key to controlling weeds such as ragweed and pigweed.
On this episode of RealAgriculture Soybean School, Syngenta Canada agronomic sales representative Brad Garlough explores how new sprayer technology can help growers get better herbicide coverage, optimize weed control, and defend the farm against herbicide resistance.
In this field near Arthur, Ont., Garlough takes a close look at John Deere’s ExactApply sprayer system and the coverage generated by front and rear-facing 3D nozzles that can cover a plant leaf that’s parallel to the ground as well as a vertical stem. Prior to the availability of 3D nozzle technology, sprayers typically relied on flat fan nozzles that couldn’t penetrate the canopy at an angle and provide adequate stem coverage.
Garlough says the sheer number of nozzles on the ExactApply also contributes to the coverage level. A standard sprayer typically has 96 nozzles, but the ExactApply has two per nozzle body, or 192. “Having the ability to go forward and backwards on every single nozzle body versus the old style where it’s every other nozzle, I would say doubles your coverage,” he adds. (Story continues after the video.)
In the video, Garlough stresses the importance of water volume as well as the correct travel speed. “We would like to stick to that 20 gallons. In some cases, with really big broadleafs, we’ll encourage customers to go to 25 gallons to really increase coverage, and increase their control.”
Garlough also stresses the important role proper spray application can play in helping manage the growing challenge of herbicide resistant weeds. Common ragweed’s ability to resist the control efforts of different herbicide groups continues to grow across Ontario. Last winter, University of Guelph weed scientist Dr. Peter Sikkema confirmed the presence of Group 14 resistance in common ragweed. His team has als0 identified the presence of four-way resistance common ragweed in Ontario.
“A half-dead weed is obviously tolerating some of the Group 14,” says Garlough. When growers more effectively spray and kill weeds they can better manage the potential for weed resistance. “A true dead weed is what we want and a half-dead weed is what’s causing these problems in a lot of cases,” he adds.
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