Maximizing Herbicide Performance: Water Volume, Tractor Speed & Nozzle Type

1. Water Volume, Tractor Speed, and Nozzle Type Effects on Spray Coverage Eric P. Prostko, Extension Weed Specialist Paul E. Sumner, Extension Ag-Engineer The University of Georgia Peanut Achievement Club - 2007

2. Factors That Influence Postemergence Herbicide Performance • weed size • rate • environment • moisture • temperature • humidity • application • water volume (GPA) • tractor speed • nozzle type

3. Current Application Trends • low water volumes • 10 GPA or less • faster tractor speeds • nozzle types • Air Induction (AI) • Turbo-Jet (TJ) • Hollow-Cone (HC) • Why?? • RR crops • More acres • Labor issues

4. U.S. Acres Planted to HerbicideResistant Varieties Includes stacked Source: NASS

7. 3.5, 5.0, 7.0 MPH 10, 15, 20 GPA XR-Flat Fan (XR-FF) and Hollow Cone (HC) Nozzles 9 replications Kromekote water sensitive cards

8. Examples of the nozzles used in these tests. Flat Fan Hollow Cone (Whirl-Jet)

9. RESULTS

10. Nozzle Type and GPA Effects - I3.5 MPH Tractor Speed LSD 0.10 = 3

11. Nozzle Type and GPA Effects - II5.0 MPH Tractor Speed LSD 0.10 = 3

12. Nozzle Type and GPA Effects - III7.0 MPH Tractor Speed LSD 0.10 = 3

13. 10 GPA - 7 MPH – HC (12% coverage) 20 GPA – 3.5 MPH – XR (FF) (45% coverage)

14. Summary • 3-way interaction between tractor speed, GPA, and nozzle type • HC nozzles provided less coverage than XR-FF nozzles • Tractor speed • FF and 20 GPA = 3.5 mph > 5.0 mph = 7.0 mph • HC and 10 GPA = 3.5 mph > 5.0 mph = 7.0 mph • HC and 15 GPA = 3.5 mph > 7.0 mph • increases in GPA improved coverage • 20 GPA > 15 GPA > 10 GPA • best coverage (45%) • 3.5 MPH/20 GPA/XR-FF • least coverage (12%) • 7.0 MPH/10 GPA/HC

15. Why is this important? • Application techniques for glyphosate (systemic) are not adequate for other types of herbicides such as paraquat (contact)!

16. Peanut Herbicides (POST)

17. www.gaweed.com