2006 Annual Report 4d.Progress report. This report serves to document research conducted under a Specific Cooperative Agreement between ARS and The Ohio State University. Additional details of research can be found in the report for the parent CRIS 3607-21620-006-00D Biological, Microclimate, and Transport Processes Affecting Pest Control Application Technology. (1) In cooperation with The Ohio State University/OARDC, spray drift potential, spray coverage, droplet size, and spray pattern width for various sizes of air induction (or low-drift) and conventional flat fan nozzles with equivalent orifice areas were investigated and compared under the laboratory conditions. Test results demonstrated that spray performances and drift reduction potential of air induction nozzles could be achieved by conventional nozzles with the same orifice size operated at very low pressure. Therefore, spray applicators can use conventional nozzles with lower cost, lower energy and less equipment maintenance to obtain desired spray performances. (2) Tests were conducted to provide guidelines for soybean growers to select economical and effective methods and equipment to apply fungicides in preventing severe soybean yield loss from Asian soybean rust. Asian soybean rust arrived in the United States in the fall of 2004. It is expected to affect almost all the soybean production areas and can cause at least 10% yield loss in the United States. Fungicides manufactured to control soybean rust are effective; however, successful control of this disease will mostly depend on proper application methods. In cooperation with The Ohio State University/OARDC, spray coverage and deposition inside soybean canopies were investigated with 10 spray application techniques. Our findings from this research were: (a) air assisted sprayers provided much higher spray penetration and coverage than conventional boom sprayers; growers should use the air assisted sprayers as their first selection if they can afford to buy them; (b) simply attaching a canopy opener can considerably improve spray deposition and coverage inside canopies for the conventional sprayers with short booms; (c) higher-price twin fan pattern nozzles recently recommended by some nozzle manufacturers for soybean rust control had very poor deposition and coverage capability inside canopies. Therefore, this research has provided comprehensive information for soybean growers and fungicide manufacturers how to select optimal spray techniques to effectively control Asian soybean rust.