The Effect of Spray Tips and Spray Volumes

The Effect of Spray Tips and Spray Volumes on Glyphosate and Paraquat Efficacy Cathy L. Minihan, Dallas E. Peterson, Robert E. Wolf, & J. Anita Dille

INTRODUCTION • Higher spray volumes and smaller spray droplets theoretically should provide the most thorough coverage assuming the spray droplets reach the intended target. • Spray volume, pressure, and spray tips influence spray droplet size. • Thorough spray coverage is probably more critical with contact than systemic herbicides.

OBJECTIVE • Determine the effect of spray tips and spray volumes on paraquat and glyphosate efficacy with early and late postemergence applications to oats.

MATERIALS AND METHODS • Location & Years: Manhattan, KS 2000, 2001 • Experimental Design: 2 x 3 Factorial Herbicides Spray Tips Spray Volumes • Herbicides: Glyphosate & Paraquat • Spray Tips: XR Flat Fan Turbo Tee. Jet Air Induction

MATERIALS AND METHODS • Spray Volumes: 47 L ha-1 (110015) 94 L ha-1 (11003) 187 L ha-1 (11006) • Spray Pressures: 262 -276 k. Pa • Early Postemergence: • Late Postemergence: Oats 15 cm Oats 50 cm • Visual Ratings: 1, 2, 4 WAT

XR Flat Fan Turbo Tee. Jet Air Induction

RESULTS AND DISCUSSION EARLY POSTEMERGENCE EXPERIMENTS 2000 -2001

Early Postemergence Oat Control 2 WAT As Influenced By Herbicide and Spray Tips, 2000. (averaged across spray volumes) a a b c d c

Early Postemergence Oat Control 2 WAT As Influenced By Spray Volume, 2000. (averaged across herbicides and tips) LSD(0. 05)=NS

Early Postemergence Oat Control 2 WAT As Influenced By Herbicides and Spray Volumes, 2001. (averaged across spray tips) a b d c c d

Early Postemergence Oat Control 2 WAT As Influenced By Spray Tips And Volumes, 2001. (averaged across herbicides) b a bc cd de e fg f g

EARLY POSTEMERGENCE 2000 HERBICIDE X SPRAY TIP SPRAY VOLUMES SIGNIFICANT NOT SIGNIFICANT 2001 HERBICIDE X VOLUME SPRAY TIP X VOLUME SIGNIFICANT

LATE POSTEMERGENCE EXPERIMENTS 2000 -2001

Late Postemergence Oat Control 2 WAT As Influenced By Spray Tips, 2000. (averaged across herbicides & volumes) LSD(0. 05)=NS

Late Postemergence Oat Control 2 WAT As Influenced By Spray Volumes, 2000. (averaged across herbicides & spray tips) a a b

Late Postemergence Oat Control 2 WAT As Influenced By Spray Tips, 2001. (averaged across herbicides & volumes) LSD(0. 05)=NS

Late Postemergence Oat Control 2 WAT As Influenced By Herbicide and Spray Volumes, 2001. (averaged across spray tips) a b c e c d

LATE POSTEMERGENCE 2000 SPRAY VOLUME SPRAY TIPS SIGNIFICANT NOT SIGNIFICANT 2001 HERBICIDE X VOLUME SIGNIFICANT SPRAY TIPS NOT SIGNIFICANT

47 L ha-1 94 L ha-1 187 L ha-1 Late postemergence paraquat 1 WAT applied with spray volumes of 47, 94, 187 L ha-1, 2000.

47 L ha-1 94 L ha-1 187 L ha-1 Late postemergence glyphosate 1 WAT applied with spray volumes of 47, 94, 187 L ha-1, 2000.

47 L ha-1 94 L ha-1 187 L ha-1 Late postemergence oat control 2 WAT with glyphosate at 47, 94, and 187 L ha-1 spray volumes , 2000.

CONCLUSIONS • Even though oat control with glyphosate and paraquat was different, the response to spray tips and spray volumes was similar. • Oat control at 47 and 94 L ha-1 was equal or better than at 187 L ha-1 with both herbicides. • Oat control with the Turbo Teejet, Air Induction, and XR Flat Fan tips was similar.

IMPLICATIONS • Lower spray volumes can provide equal or better weed control with more efficient use of time and resources. • Use of new spray tips that produce larger spray droplets reduce the risk of spray drift while maintaining herbicide efficacy.

FUTURE RESEARCH • Confirm results with different herbicides and weeds. • Evaluate new spray tips and delivery systems as they are introduced into the market.

ACKNOWLEDGEMENTS • Kansas State University Research and Extension • Syngenta • Successful Farming