ARS | Publication request: AERIAL APPLICATION METHODS FOR INCREASING SPRAY DEPOSITION ON WHEAT HEADS

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 30, 2006
Publication Date: May 22, 2006
Citation: Fritz, B.K., Kirk, I.W., Hoffmann, W.C., Martin, D.E., Hofman, V., Hollingsworth, C., McMullen, M., Halley, S. 2006. Aerial application methods for increasing spray deposition on wheat heads. Applied Engineering in Agriculture. 22:357-364.

Interpretive Summary: Fusarium head blight (FHB) is a major disease of wheat and barley in several grain production regions in the U.S., for which cultural practices, resistant cultivars, and fungicides have had limited effectiveness and erratic results. Fungicide applications can suppress FHB but thorough coverage of the wheat head must be achieved. Spray deposition on wheat heads and artificial targets close to the wheat heads were investigated using six aerially applied treatments spanning two droplet sizes and three spray rates. Generally, lower spray rates along with larger droplet sizes resulted in greater tracer deposits, and sprays with smaller droplet sizes with the same spray rate provided greater droplet densities on the target area. These results coupled with future post harvest statistics are expected to provide guidance for optimizing aerial spray deposits for suppression of Fusarium head blight.

Technical Abstract: A research priority of the U.S. Wheat and Barley Scab Initiative is the development and evaluation of aerial application technologies that enhance the efficacy of fungicides with aerial spray applications. The ARS Aerial Application Technology research team at College Station, Texas, along with extension specialists, plant pathologists, and crop scientists from North Dakota State University and the University of Minnesota initiated research to assess aerial spray technologies in an effort to increase spray deposits on wheat heads for Fusarium head blight suppression. Three aerial spray trials were conducted in North Dakota and Minnesota. Six treatments were applied in a factorial design with three replications for each trial. Multiple sub-samples of wheat heads and artificial collectors were collected and analyzed to assess and describe spray deposits from the specified treatments. Colorimetry and image analysis were used to quantify and characterize spray deposits. Data analysis indicated no significant trends spanning all sampling methods, but generally showed increased tracer deposits on targeted area at lower spray rates with larger droplet sizes. Results also indicated that for similar spray rates smaller droplet spectra sprays resulted in greater droplet densities on the targeted area. Results from this study are expected to provide guidance for aerial fungicide applications for suppression of Fusarium head blight.