Submitted to: Aspects of Applied Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 1, 2005
Publication Date: January 10, 2006
Citation: Derksen, R.C., Zhu, H., Ozkan, H.E., Dorrance, A.E., Krause, C.R. 2006. Effects of Air-Assisted and Conventional Spray Delivery Systems on Management of Soybean Diseases. International Advances in Pesticide Application--Aspects of Applied Biology. 77:415-422. Technical Abstract: Sclerotinia Stem Rot (SSR) is a major soybean disease in the north central region of the United States. Asian Soybean Rust (ASR) is a looming threat to the industry. The primary infection site is flower petals for SSR and leaves for ASR. Infection for both diseases tends to occur in areas with higher moisture retention, such as deep in dense canopy. SSR related deposition studies were conducted in narrow- (18 cm) and wide-spaced (76 cm) soybean planting systems. Application techniques included air-assist spraying and conventional broadcast application using air induction, hollow cone, and traditional flat-fan nozzles. In the SSR management experiment, artificial targets were positioned in the lower and middle sections of the canopy. These simulate the primary infection site and flower buds. In the ASR management trials, artificial targets positioned in the lower and middle canopy areas simulated spray retention on leaves. Faster travel speeds reduced spray deposits on targets in the lower canopy area. An air-assist sprayer produced the highest deposits in both the wide and narrow row planting systems used in the SSR trial. Conventional, broadcast sprayer treatments produced no significant differences in deposits in the SSR management trial. SSR efficacy trials showed all sprayer/nozzle treatments reduced incidence of SSR compared to a no-spray control plot. Only the air-assist sprayer treatment resulted in higher yields in the SSR trials.