Growers using an air-induction nozzle for fungicide sprays this spring should make sure its droplet size is at the finer end of the spectrum, says Clare Butler-Ellis, research manager of The Arable Group‘s Silsoe spray applications unit.
“The droplet size produced by commercial air-induction nozzles are not all the same,” she said. Those producing small droplets did not affect efficacy of fungicides in trials, but larger droplets could, although they were better at reducing drift, she explained.
Forward speeds of 16kmh could also affect efficacy, limited research had shown, but water volumes didn’t seem to have much impact.
There was also little evidence that higher water volumes increased penetration of fungicides, although angling sprays using small droplet air induction nozzles could achieve that affect, she suggested.
“But if you’re going to put me on the spot, then an 025 air-included nozzle at 12kmh giving 100 litres/ha would be a good choice for most fungicide applications.