Submitted to: National Soybean Rust Symposium
Publication Type: Proceedings
Publication Acceptance Date: 12/14/2006
Publication Date: 12/28/2006
Citation: Derksen, R.C., Ozkan, H.E., Zhu, H., Dorrance, A. 2006. Nozzle and Equipment Considerations for Improved Coverage in the Soybean Canopy: A Summary of the Work Done in Ohio. National Soybean Rust Symposium.
Technical Abstract: Asian Soybean Rust (ASR) poses a significant risk to soybean production in the U.S. From observations in South American, it is known that ASR rust infects foliage in the lower part of a canopy. Infection is most likely to occur once the canopy is nearly fully developed and most difficult to treat. While there are fungicides available that can help manage ASR, there are few guidelines on how to effectively apply fungicides to the most susceptible parts of the soybean canopy. Field trials were designed to help identify methods for most effectively applying ASR fungicides. Measures of performance included fluorescent tracer, water sensitive paper (WSP), and fungicide residue analysis. Application treatments included conventional broadcast and air-assisted delivery. Nozzle types evaluated included flat-fan, twin-fan, low-drift, and cone. Cone and flat fan styles were also evaluated using air-assisted delivery. Differences in the canopy in 2005 and 2006 affected the results. It was more difficult for twin-fan type of nozzles to treat the taller and denser canopy in 2005 than in 2006. Overall, medium spray quality treatments performed well at application rates of 15 gpa. Single-fan, flat-fan nozzles used for conventional broadcast applications, generally performed better than cone or twin-fan nozzles. Air-assisted delivery was generally superior to conventional delivery. Spray coverage and spray deposits lower in the canopy were both higher for the air-assisted delivery. There was no difference between the performance of cone and flat-fan nozzles on air-assisted delivery sprayers. This research will help educators, formulators and producers identify how equipment options that will increase the efficacy of their applications and provide better protection from ASR infection.