Effectiveness of Extended Range Flat Fan Nozzles and Air Induction Nozzles with Glyphosate and Paraquat

Abstract

Weed control was evaluated applying glyphosate with extended range flat fan nozzles (XR 11003VS) and air induction flat fan nozzles (11003VS AI). In another experiment, paraquat was used with extended range flat fan nozzles (11003VS XRC) and air induction flat fan nozzles (AIC 11003VS). With water sensitive paper was determined the distribution and droplet size of the XR 11003VS and AI 11003VS nozzles applying 250 and 165 L/ha. The air induction nozzle had larger droplets than the extended range. Decreasing the application volume from 250 to 165 L/ha decreased coverage with both nozzles. In field trials, the effectiveness of the air induction (AI 11003VS) and extended range nozzles (XR 11003VS) with glyphosate was determined, also the efficacy of the AI (AIC 11003VS) and extended range nozzles (XRC 11003VS) with paraquat. We used a factorial experiment arranged in a randomized complete block design with six replicas. Glyphosate was applied at the recommended active ingredient dose of 890 g/ha and 75% of the recommended dose (668 g/ha); with paraquat the recommended dose was 500 g/ha of active ingredient and 75% of the recommended dose (375 g/ha). We determined the percentage of visual damage on African Bermuda grass (Cynodon nlemfuensis) with glyphosate, and crabgrass (Digitaria spp.) with paraquat. With glyphosate there was no statistical difference in the interaction nozzle by dose, or between nozzle types. There was a decrease in weed control when the glyphosate application rate was reduced from 890 g/ha of active ingredient to 668 g/ha. With paraquat there was no statistical difference found for the interaction of nozzle by dose, or between the two types of nozzles. There was no statistical difference between the doses of paraquat in the first evaluation, but in the second and the third there was less weed control when dose was reduced from 500 g/ha of active ingredient to 375 g/ha. There was no difference in the weed control between nozzles with any of the doses.

DOI: http://dx.doi.org/10.5377/ceiba.v51i2.1107