Air-assisted spraying of arable crops, in relation to deposition, drift and pesticide performance

Abstract

Field experiments comparing spray deposition, spray drift and the biological efficacy of one herbicide and a number of fungicides in several crops treated by hydraulic nozzle sprayers and a novel air-assisted sprayer (Degania) are reported. Air-assisted sprays using fine-spray hollow-cone nozzles spaced at 25 cm were compared with coarser sprays applied at similar or greater volumes from standard hydraulic pressure nozzles. The quantity of spray deposited on different crop types was generally similar from both methods of application, but the uniformity of droplet distribution from the air-assisted system was usually superior. The air-assisted sprayer generally produced more drift than the standard sprayer. All spray methods generally produced similar biological results at full and half pesticide dose rates. A Brussels sprouts crop normally considered as being difficult to spray showed some biological benefits from air-assisted spraying.