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Influence of application equipment on deposition of spray droplets in wheat canopy

Ozkan, H.E., Paul, P., Derksen, R.C., Zhu, H.
Aspects of applied biology / 2012 v.114 pp. 317
application methods, canopy, disease control, droplets, field experimentation, foliar diseases, fungicides, infection, leaves, nozzles, pathogens, spray coverage, wheat
Fungicides manufactured to control various diseases in wheat are effective; however, successful control of diseases will mostly depend on proper application methods. The ability to provide protection across the wheat plant is important because different infections may occur on different parts of the plant canopy depending on the pathogen. The objective of this work was to identify effective application parameters to apply adequate amount of fungicides for protection against spike and foliar diseases of wheat. Field trials were conducted in 2009, 2010 and 2011 to evaluate the effect of different nozzle types and spray qualities on spray coverage at three levels within the wheat canopy: at the height of the spike, flag leaf, and 30 cm below the flag leaf. Nozzles selected for this three-year study included two single flow pattern nozzles (XR 8003 and XR11003) with respectively Medium and Fine spray qualities, and three twin-flow pattern nozzles (TJ, TTJ, TT Duo) with spray qualities of Fine, Medium and Coarse. Water Sensitive Paper cards placed vertically at spike level (vertical), at the height of the flag leaf (horizontal top), and 30 cm below flag leaf (horizontal middle). In all three years, the mean percent spray coverage on vertical, horizontal top, and horizontal middle targets varied from 5–15%, 18–35%, and 8–28%, respectively, across all five treatments. The three nozzles with double spray patterns outperformed the two single-flow pattern nozzles in deposition on vertical targets representing wheat spike. However, single-flow pattern nozzles produced higher coverage on middle horizontal targets than the twin-flow nozzles.