2007 Annual Report 1a.Objectives (from AD-416) Achieve efficient and effective pesticide spray applications for nursery, horticulture, orchard and field crops. 1b.Approach (from AD-416) Develop innovative technologies to reduce pesticide use and worker hazards, insure food safety and crop quality, and promote competitiveness and production efficiency. Minimize spray drift, determine the effects of physical properties of spray mixtures, drift control agents, and meteorological conditions on spray performances. Determine dynamic characteristics of droplet deposition and penetration into floral, greenhouse and field crops. Develop inline injection systems for agricultural sprayers to eliminate left-over tank mixtures with minimum lag time and uniform spray mixture. Investigate new spray methods including fluid dynamic simulation to improve spray performance and reduce pesticide use and drift potential in nursery and horticutlural crops. 3.Progress Report This report documents research conducted under a Specific Cooperative Agreement between ARS and The Ohio State University. 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. It is important to understand the evaporation process of pesticide droplets on targets for increasing the control efficiency of foliar applied insecticide and fungicide spray applications. Laboratory-based research was launched and sequential images for the evaporation process of water droplets mixed with different chemical formulations in a small environmental chamber were obtained through a stereoscope under the experimental conditions with five droplet sizes and three relative humidity conditions. The spray mixtures included different combinations of water, a nonionic colloidal polymer drift retardant, a nonionic surfactant, insecticides and fungicides. The droplet evaporation was investigated on the surfaces of crabapple leaves, clean glass slides and glass slides covered with wax. The evaporation time on a clean glass slide and on a waxy glass slide was used as references for the data on the surface of leaves. Evaporation time and evaporation rate of each single droplet was calculated according to the total number of the sequential images and its intervals. Among the spray mixtures investigated, the droplets containing the drift retardant had the longest evaporation time, and the droplets containing the surfactant had the shortest evaporation time. The surfactant after added into spray mixtures reduced the spray mixture surface tension, and helped the droplet to spread more evenly, resulting in better spray coverage and greater residual area on leaf surfaces. The mean evaporation time of 200, 400, and 800 µm droplets containing different insecticide or fungicide formulations without additives at 60% relative humidity on crabapple leaves was 31.7, 64.7, and 212.8 s, respectively. The mean evaporation time of the same size droplets containing the same insecticide or fungicide formulations, but mixed with the surfactant was 22.6, 49.3 and 161.6 s, respectively. On crabapple leaves, the evaporation time of 400 µm droplets without the drift retardant and surfactant increased from 42.3 to 86.1 s when the relative humidity increased from 30 to 90%. Also, for the same droplets at 60% relative humidity, the evaporation time was 72.7 s when they were on the clean glass slides and was 110.0 s when they were on the waxy glass slides. Therefore, spray additives, target surface fine structure and relative humidity greatly influenced the evaporation time of spray droplets. Spray coverage and deposition inside soybean canopies were investigated with six different spray application techniques in a commercial field. Cooperator’s Designated Representative directly worked with the ADODR to plan and execute the project. They met daily to discuss the project progress.