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Title: The effects of spray application rate and droplet size on applications to control soybean rust

item Derksen, Richard
item Zhu, Heping

Submitted to: ASABE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: 7/1/2009
Publication Date: 7/1/2009
Citation: Bretthauer, S.M., Mueller, T.A., Bode, L.E., Derksen, R.C., Zhu, H. The effects of spray application rate and droplet size on applications to control soybean rust. Presented at the 2008 American Society of Agricultural and Biological Engineers Annual International Meeting. Paper Number 084219 Available:

Interpretive Summary:

Technical Abstract: Management of foliar soybean diseases such as Asian Soybean Rust requires good canopy penetration and thorough spray coverage. The purpose of this study was to examine how spray application rate and spray droplet size affect the efficacy of rust applications in wide-row (36 inch) soybean plantings. Treatments included medium (M) spray quality application at 5 and 15 gpa and very coarse (VC) spray quality application at 5 and 15 gpa. Spray coverage, deposition, soybean rust severity, and yield were measured to evaluate the effectiveness of these treatments. Coverage and deposition were measured in the upper and lower parts of the canopy. The VC spray quality treatment at 15 gpa had the highest coverage and deposition in both the upper and lower canopy. No significant differences in rust severity or yield were observed between the treatments. All treatments had significantly lower rust severity than an untreated control. These results demonstrated that a larger droplet spectrum application, while reducing spray drift, could also potentially provide effective control of rust in wide-row soybean plantings.