2007 Annual Report 1a.Objectives (from AD-416) (1)To develop a custom-designed, five-port, aira-assist sprayer to improve spray penetration into dense nursery canopies while minimizing off-target loss, and (2)to determine optimal sprayer characteristics such as air-velocity and nozzle height to provide sufficient spray deposition for effective pest control within dense canopies. 1b.Approach (from AD-416) The hypothesis of the new sprayer design is that spray penetration into dense nursery crops can be improved by dividing a conventional large diameter air jet to several small diameter air jets arranged in a flat fan shape. Small air jets due to high speed can inject spray droplets into deeper dense canopies and at the same time the adjacent air jets will create eddies to spread out droplets in surrounding areas within canopies. Small air jets due to their flat fan pattern arrangement can cover much wider spray width than a conventional large diameter air jet. In contrast, using a conventional large diameter air jet may easily damage canopies due to high air volume and speed. In cooperation with the ARS Application Technology Research Unit, Wooster, OH, this research will include the following: An improved air assisted sprayer with five-port nozzles will be developed and modified to discharge sufficient spray droplets into dense nursery canopies. Spray droplet size and spray pattern uniformity at various distance from nozzle orifice will be measured with a particle imaging size and velocity analyzer. Field tests will be conducted to investigate spray deposition and air velocity distribution at various levels within several dense canopies, various nozzle heights, and application rates to evaluate new and improved sprayer performance. Several dense nursery crops will be selected for field experiments. Correlations between deposition and air velocity within canopies will be determined under field conditions. Reliability and durability of new sprayers will be continuously tested under field production conditions for three years. 3.Progress Report This report documents research conducted under a Specific Cooperative Agreement between ARS and Herman Losely & Son, Inc. Additional details of the research can be found in the report for the parent project 3607-21620-006-00D Biological, Microclimate, and Transport Processes Affecting Pest Control Application Technology. A specially designed five-port, air-assist sprayer was developed and investigated to apply pest control agents in nursery field productions. Spray deposits at the top, middle, and bottom of canopies were characterized using fluorescence detection. Dynamic air velocities corresponding to the deposit sampling locations inside and outside the canopy were measured at the time when the sprayer passed over the canopies. The sprayer performances, the sprayer reliability, and other operating parameters were tested in the fields to control insects and diseases for dense nurseries during the entire growing season. Document monitoring activities for the project within Question 3: Site visits and telephone calls were used as needed to monitor the project progress.