COMPARISON OF SPRAY DRIFT DURING POSTEMERGENCE HERBICIDE APPLICATIONSTO TURFGRASS

Field tests showed that the lawn spray-gun with a 4 gpm lawn tip reduc ed the percentage of application volume deposited 90 cm to 210 cm down wind from the spray swath edge when compared with XR8004 flat-fan or R A-6 wide angle hollow cone applications at wind speeds between 4.7 and 14.4 km/h. The percentage of applied volume collected at 210 cm downw ind from the XR8004 flat-fan applications was 5 and 16 times greater t han the percentage from the RA-6 Raindrop nozzle and lawn spray-gun ap plications, respectively. Visible injury along with height increases a nd fresh weights from tomato plants located downwind from the applicat ions concur with spray-drift data for all nozzle types. Triclopyr inju ry decreased as the distance from the swath edge increased. All tomato plants located downwind up to 210 cm from the XR8004 flat-fan applica tions were visibly injured(15 to 40%); whereas, only plants less than 150 cm downwind from the RA-6 Raindrop applications and less than 90 c m downwind from the lawn spray-gun applications were injured (2 to 8%) .