2008 Annual Report
1a.Objectives (from AD-416)
1) Develop and integrate GIS, GPS, and other systems for efficacious precision application;.
2)develop technologies that account for material released during crop spray applications;.
3)develop and evaluate nozzles and other application technologies and spray formulations with emphasis on reducing driftable fines and improving efficacy;.
4)determine effects of meteorological conditions on off-target movements of sprays;.
5)develop and evaluate systems for aerial delivery of new crop pest management materials.
1b.Approach (from AD-416)
Utilizing engineering and biological principles, laboratory and field studies will be conducted to evaluate the effects of various aerial application parameters, such as droplet size spectrum and equipment, on efficacy and off-target movement of crop production and protection materials. Efforts will focus on maximizing efficacy and spray deposition, through equipment or formulation modifications, so minimal amounts of pesticides will be needed for crop production and protection. Spray deposition and movement will be quantified using various plant and artificial collectors in conjunction with chromatography and spectrofluorometry. Pest control efficacy will be evaluated using lab and field assessments. Novel application equipment, spray models, and product formulations will be developed.
Work under this project during FY 2008 resulted in significant progress in improving the efficacy of crop production and protection materials, enhancing the use of remote sensing and precision application in crop production systems, and spray droplet movement and collection. Studies were completed, under various aerial application conditions, on effects of water hardness and spray adjuvants on spray droplet spectra, which affect both spray efficacy and drift. Field studies were conducted that established the application parameters to maximize efficacy of crop protection materials for control of thrips, fleahoppers, corn earworms, and weeds. A spray system was developed for an unmanned autonomous vehicle (UAV) that can be used to treat small, site-specific areas within a field. The UAV and other USDA-owned aircraft were fitted with multispectral cameras to take airborne images of crops and to locate and identify weeds and diseases in corn, cotton, and sorghum fields, and in pecan groves. The assessment of spray droplet movement in the environment was improved through the construction of a low wind speed dispersion tunnel and by the subsequent collection efficiency and bioassay cage evaluations that were conducted in the tunnel. Project scientists continue to serve as experts in the aerial application industry and were sought out for advice and consultation by industry and academic research personnel, by officials with the EPA, Dept. of Homeland Security, Dept. of Defense, USDA-APHIS, and numerous state representatives from around the nation. (NP 305, Components 1A, 1B, Problem Statements 1A.2, 1A.3, 1A.4, 1B.2. Also contributes to NP 304, Components V, VI, Problem Statements V.E, VI.C, VI.D, VI.E)
Effectiveness of Bioassay Cages as Related to Wind Speed:
Insecticide efficacy and control success is frequently assessed using sentinel or mosquito bioassay cages, but few studies have investigated how varying wind speed and screening material used in the construction of the cages may affect spray droplet entry into cages. To protect the public from mosquitoes that can carry West Nile Virus, Eastern Equine Encephalitis, or other insect-transmitted diseases, public health officials and researchers must rely on the use of bioassay cages to measure the efficacy of insecticides and application methodologies. It is therefore critical that the bioassay cages accurately reflect spray efficacy on natural populations of mosquitoes. Scientists in the Areawide Pest Management Research Unit at the Southern Plains Agricultural Research Center, College Station, Texas, accurately determined the effects of wind speed and screening material on spray droplet penetration into bioassay cages, and their effects on spray efficacy assessments. This accomplishment will provide critical guidance on the impact of wind speed and cage design/construction on ultra low volume spray droplet movement into bioassay cages, and will lead to much more accurate data for use by public health officials in their ongoing efforts to protect the public against serious insect-transmitted diseases. (NP 305, Component 1A, Problem Statements 1A.2, 1A.4)
Adjuvant Utilization to Reduce Spray Drift from Aerial Applications:
Spray drift from the aerial application of pesticides has been recognized as a concern for the environment. The physical properties of spray additives or adjuvants are among the most important factors that affect atomization of a spray; applicators can use appropriate adjuvants to reduce spray drift but only if appropriate information on adjuvant properties is available to them. Scientists in the Areawide Pest Management Research Unit at the Southern Plains Agricultural Research Center, College Station, Texas, defined the physical properties of certain spray adjuvants and also correlated adjuvant physical properties to spray droplet spectra. This accomplishment clearly established that the physical properties of spray adjuvants have great influence on spray characteristics. Aerial applicators will use this information to appropriately select spray adjuvants that will reduce spray drift, thus increasing on-target deposition and minimizing drift which can have adverse environmental consequences. (NP 305, Components 1A, 1B, Problem Statements 1A.2, 1A.4, 1B.2)
Improved Variable-Rate Aerial Application Technologies and Protocols:
Variable-rate technologies in agriculture offer the capability to apply crop protectants only where needed and in the amounts needed to adequately protect crops. In order for variable-rate applications to be made, vast amounts of remotely sensed data, such as multispectral images obtained from aircraft or satellites, must be collected, analyzed, and then translated into data that applicators can use. Scientists in the Areawide Pest Management Research Unit at the Southern Plains Agricultural Research Center, College Station, Texas, employed both ground- and aerial-based remote sensing techniques to enhance the collection and processing of data needed to make variable-rate applications. Ground and aerial applicators will use the methodologies, technologies, and protocols developed in this accomplishment to develop accurate and user-friendly variable-rate, field-based prescription maps. The end result will be effective variable-rate application procedures, utilized widely by aerial applicators, that will significantly reduce chemical input costs, application time, aircraft fuel expenditures, and potentially negative environmental impacts. (NP 305, Component 1A, Problem Statement 1A.4)
Collection Efficiency of Airborne Spray Flux Samplers:
Determination of the movement and ultimate fate of agricultural sprays within and off of target areas is a critical concern for applicators, landowners, and researchers. There are numerous methods for the quantitative assessment of the volume of suspended spray material; however, without knowing the fraction of the total spray volume actually sampled by the collector, comparisons between collectors, comparisons with modeled data, and mass balance calculations are not possible. Scientists in the Areawide Pest Management Research Unit at the Southern Plains Agricultural Research Center, College Station, Texas, designed, constructed, and tested a low speed spray dispersion tunnel and experimental methodology to determine the collection efficiency of several commonly used spray flux collectors. The resulting protocols developed and collection efficiencies established permit total accountancy of applied materials and increased understanding of how agricultural sprays are transported and deposited in the environment. This accomplishment will be of significant value to aerial applicators in improving application efficiency and efficacy. (NP 305, Component 1A, Problem Statements 1A.2, 1A.4)
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Fritz, B.K., Hoffmann, W.C. 2008. Collection efficiency of various airborne spray flux samplers used in aerial application research. Journal of ASTM International. 5(1):Paper ID JAI01493.
Hoffmann, W.C., Bagley, W.E., Fritz, B.K., Lan, Y., Martin, D.E. 2008. Effects of water hardness on spray droplet size under aerial application conditions. Applied Engineering in Agriculture. 24(1):11-14.
Lan, Y., Hoffmann, W.C., Fritz, B.K., Martin, D.E., Lopez, J. 2008. Spray drift mitigation with spray mix adjuvants. Applied Engineering in Agriculture. 24(1):5-10.
Lopez, J., Hoffmann, W.C., Latheef, M.A., Fritz, B.K., Martin, D.E., Lan, Y. 2008. Adult vial bioassays of insecticidal toxicity against cotton fleahopper, Pseudatomoscelis seriatus (Reuter) (Hemiptera: Miridae). Journal of Pesticide Science. 33:261-265.
Martin, D.E., Lopez, J., Hoffmann, W.C., Fritz, B.K., Lan, Y. 2007. Field evaluation of spinosad aerial applications for thrips control on cotton. Southwestern Entomologist. 32(4):221-228.
Hoffmann, W.C., Walker, T.W., Smith, V.L., Martin, D.E., Fritz, B.K. 2007. Droplet-size characterization of handheld atomization equipment typically used in vector control. Journal of the American Mosquito Control Association. 23(3):315-320.
Hoffmann, W.C., Hewitt, A.J., Ross, J.B., Bagley, W.E., Martin, D.E., Fritz, B.K. 2008. Spray adjuvant effects on droplet size spectra measured by three laser-based systems. Journal of ASTM International. 5(6):Paper ID JAI101233.
Hoffmann, W.C., Walker, T.W., Martin, D.E., Barber, J.A.B., Gwinn, T., Smith, V.L., Szumlas, D., Lan, Y., Fritz, B.K. 2007. Characterization of truck-mounted atomization equipment typically used in vector control. Journal of the American Mosquito Control Association. 23(3):321-329.
Lan, Y., Lin, X., Kocher, M.F., Hoffmann, W.C. 2007. Development of a PC-based data acquisition and control system. International Agricultural Engineering Journal. 9:1-11.
Zhang, Z., Tong, J., Chen, D., Lan, Y. 2008. Electronic nose with an air sensor matrix for detecting beef freshness. Journal of Bionics. 5:67-73.
Lopez, J., Lan, Y., Latheef, M.A., Hoffmann, W.C., Fritz, B.K., Martin, D.E. 2008. Laboratory evaluation of novaluron for toxicity to nymphal instars of field collected southern green stink bug on cotton. Southwestern Entomologist. 33:119-127.