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United States Department of Agriculture

Agricultural Research Service



2010 Annual Report

1a. Objectives (from AD-416)
1) Improve existing aerial application technologies to maximize efficiency and biological efficacy of crop production and protection compounds with minimal spray drift and impact to non-target systems. Subobjective 1A: Develop and implement standard procedures for evaluating drift reduction technologies (DRTs) and assessing biological impacts of sprays in crop canopies. Subobjective 1B: Develop and optimize the use of autonomous unmanned aerial vehicles (UAVs) for pest control. Subobjective 1C: Assess biological impacts of spray drift. 2) Develop remote sensing and variable rate aerial application systems that enhance detection, prevention, and control of plant diseases, nutritional deficiencies, or insect damage in annual and perennial crops. Subobjective 2A: Characterize spatial variability of crop conditions using multispectral imaging to develop treatment maps for use with site-specific aerial application systems. Subobjective 2B: Integrate remote sensing and variable rate aerial application technologies to optimize crop management strategies. Subobjective 2C: Develop sensors that rapidly and/or remotely detect pest presence, crop condition, spray droplets, and volatile organic compounds. Subobjective 3D: Adapt autonomous unmanned aerial vehicles (UAVs) for remote sensing of crop conditions. 3) Develop, enhance, and implement decision support systems that improve user ability to select and operate application equipment and schedule spray treatments that optimize biological efficacy. Subobjective 3A: Correlate aerial spray dispersion model estimates with off-target biological effects and in-swath deposition. Subobjective 3B: Develop and implement crop growth and management decision systems to optimize aerial applications.

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 spray formulation and droplet size spectrum, on aerial application efficiency and biological efficacy. Efforts will focus on the integration of remote sensing and variable rate application systems to maximize the efficacy of crop production materials while minimizing any off-target impact from these sprays. Decision support systems will be developed that help applicators, farmers, and crop consultants in making the correct treatment decisions to protect a crop from pests. This project will develop and implement new and improved aerial application technologies for safe, efficient, and sustainable crop production and protection.

3. Progress Report
Progress was made in FY 2010 on all three objectives and their subobjectives. Project work 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 modeling. Under Objective 1, tests were conducted in high-speed and low-speed wind tunnels to determine the levels of spray drift mitigation from a number of spray nozzles and formulations. These projects support the EPA Drift Reduction Technology Program. The Unmanned Aerial Vehicles (UAVs) and other USDA-owned aircraft were fitted with multispectral cameras to take airborne images of crops and to locate and identify weeds and disease states in corn, cotton, and sorghum fields, and in pecan groves; however, during the early testing stage the UAV crashed and is being repaired. Biological assessments with glyphosate were conducted in laboratory and field trials. Under Objective 2, a volatile organic compound analyzer was designed and tested in laboratory and field trials. Remote sensing studies were conducted that combine and correlate crop physiology sensor measurements with the project's airborne multispectral images. Under Objective 3, multidata fusion techniques and technologies are being developed, which combine data from multiple sensors. This combined data will then be used to make spray application treatment decisions for the crops being investigated. Using results from Objectives 1 and 2, significant progress was made in development of spray deposition and drift models, which will be utilized to help spray applicators make more informed decisions on issues related to spray application needs, how decisions should best be made, and ways to minimize the chances of off-target spray drift. Project scientists during FY 2010 served on numerous occasions as experts in the aerial application industry and were sought out for advice and consultation by industry and academic research personnel, and by officials with the EPA, Dept. of Homeland Security, Dept. of Defense, USDA-APHIS, and representatives from numerous state agencies and organizations.

4. Accomplishments
1. Drift reduction technology evaluations. Drift associated with spray application of crop production and protection products is an ongoing concern for the spray application industry. An increasing number of drift-reducing technologies are being developed and marketed for use with agricultural chemicals in aerial application treatments, but there have been no objective scientific assessments of the relative effectiveness of these various technologies in reducing spray drift. ARS researchers at College Station, Texas, developed and evaluated protocols for testing various drift reduction technologies in both high- and low-speed wind tunnels. This accomplishment will benefit both the agricultural application and regulatory communities because it provides objective, science-based information on the strengths and weaknesses of various drift reduction technologies. With increased demands placed on American farmers for higher crop production and from a changing climate, aerial applicators must ensure that each and every spray application provides the maximum benefit to the crop being sprayed. Appropriate utilization of these testing protocols will greatly support the commitment by all players in the aerial application industry to make applications in full compliance with all regulatory requirements and in an effective and environmentally sensitive manner.

2. Optimized aerial application treatments. With rising operational costs, including fuel and chemical inputs, and with an increasing concern and awareness of the damaging effects of spray drift away from targeted treatment areas, it is critical that aerial applicators maximize the efficiency of the spray treatments they apply. ARS researchers at College Station, Texas, evaluated conventional and innovative application technologies, at varying spray rates and droplet sizes, to determine optimum deposition on the specified target. The work showed that optimum spray deposition within a dense plant canopy can be achieved with significantly larger droplets than those found in small-droplet sprays that are highly driftable and that can thus cause damage to nontargeted plants and other negative environmental effects. This accomplishment is important because it provides guidance to the aerial application industry on the proper use of spray treatments that will provide the desired results while significantly reducing off-target movement of the sprays and the adverse environmental impacts that can result. These results will also help applicators to address new spray conditions and requirements that may develop due to climate changes in their region.

3. A monitoring system for detecting herbicide-treated fields. The effectiveness of herbicide treatments against pest weeds can vary substantially among different fields, and new methods are needed to accurately map herbicide performance over entire fields or even multiple field complexes. ARS researchers at College Station, Texas, showed that a type of instrument that measures light reflectance off plant surfaces can be effectively used to detect and measure the relative weed-killing effects of the herbicide glyphosate. The technique, known as multispectral reflectance, can be adapted for use on either aerial or ground-based application equipment. The work is important because it provides a new approach to accurately evaluate herbicide effectiveness under real-world conditions, with the ultimate result that herbicide application protocols can be adjusted to assure maximum effectiveness with a minimum of chemical used.

4. New application procedures reduce herbicide resistance. The herbicide glyphosate (Round-Up) is becoming less and less effective as weeds develop resistance to it. This requires applicators to use more and more glyphosate in their treatments, which increases costs to both applicators and farmers, and which further exacerbates the weed resistance phenomenon. To address this growing problem, ARS researchers at College Station, Texas, studied how spray droplet size affects glyphosate effectiveness. The work showed that, all other things being equal, a higher spray droplet density (number of droplets per given area) results in better weed control. This knowledge allows applicators to adjust their application equipment in a manner to achieve good weed kill while using significantly less glyphosate and resulting in significant cost savings; an added benefit is that using less glyphosate to achieve the desired result also serves to slow down the process of weeds developing glyphosate resistance. Increasing the useful lifetime of an important and environmentally friendly herbicide like glyphosate also pushes into the future the need to shift to more expensive, environmentally harsh chemicals for weed control.

5. Hand-held machine for assessing two-spotted spider mite damage in cotton. The two-spotted spider mite is an important pest of cotton and many other field crops. Early detection of plant damage caused by the mite is difficult because initial infestations tend to be scattered in small areas in the field. ARS researchers at College Station, Texas, adapted a hand-held light-reflecting (multispectral) instrument to detect the mite in growing cotton and beans. The instrument is capable of "remotely" and reliably distinguishing mite-infested from non-infested plants, and is also capable of differentiating between light, medium, and heavy spider mite infestations on cotton. This new technology will be very useful in detecting early spider mite infestations in cotton and other crops, and will guide rapid-response control procedures to assure effective protection of crops from mite damage, using the lowest amount of pesticide possible and with a minimum of adverse environmental impacts.

5. Significant Activities that Support Special Target Populations
Project scientists serve as formal collaborators on a USDA National Institute for Food and Agriculture grant proposal submitted by scientists at Prairie View A&M University (an 1890 institution). Work under the grant, if funded, will target development of an efficient method for analyzing light reflectance (multispectral) images captured by appropriate instrumentation mounted on agricultural aircraft. The work will focus on images captured from airborne platforms, with the goal of developing a user-friendly image processing software system to analyze incoming data in real time and in a manner to permit variable-rate spraying of agricultural chemicals in essentially immediate (much less than one second) response to varying pest infestation levels. Project scientists will bring expertise to the work that is not available at the University, and thus our participation is critical to project success. Our efforts will train students and greatly expand the research horizons of University permanent research staff. The multidisciplinary nature of the work will impact in a highly positive manner on agriculture, engineering, mathematics, and computer science programs at the University, and will better position University researchers to be more competitive in attracting research funds in the future. Importantly, this cooperative work will generate new technology for more efficient, cost-effective, and environmentally sensitive control of agricultural pests through aerial spray application technology that is adaptable in real time to variable pest infestations across given crop fields.

Review Publications
Farooq, M., Hoffmann, W.C., Walker, T., Smith, V., Robinson, C., Dunford, J., Sutherland, I.W. 2009. Samplers for evaluation and quantification of ultra-low volume space sprays. Journal of the American Mosquito Control Association. 25:521-524.

Barber, J., Greer, M., Fritz, B.K., Hoffmann, W.C. 2009. Aerosol sampling: Comparison of two rotating impactors for field droplet sizing and volumetric measurements. Journal of the American Mosquito Control Association. 25:474-479.

Lan, Y., Huang, Y., Martin, D.E., Hoffmann, W.C. 2009. Development of an airborne remote sensing system for crop pest management: System integration and verification. Applied Engineering in Agriculture. 25(4):607-615.

Groot, A.T., Inglis, O., Bowdridge, S., Santangelo, R., Blanco, C.A., Lopez, J., Teran Vargas, A., Gould, F., Schal, C. 2009. Geographic and Temporal Variation in Moth Chemical Communication. Evolution. 63(8):1987-2003.

Hoffmann, W.C., Farooq, M., Walker, T.W., Fritz, B.K., Szumlas, D., Bernier, U.R., Hogsette Jr., J.A., Lan, Y., Huang, Y., Quinn, B.P., Smith, V.L., Robinson, C.A. 2009. Canopy penetration and deposition of barrier sprays from electrostatic and conventional sprayers. Journal of the American Mosquito Control Association. 25:323-331.

Fritz, B.K., Parker, C.T., Lopez, J., Hoffmann, W.C., Schleider, P.G. 2008. Deposition and droplet sizing characterization of a laboratory spray table. Applied Engineering in Agriculture. 25:175-180.

Huang, Y., Hoffmann, W.C., Lan, Y., Wu, W., Fritz, B.K. 2009. Development of a Spray System for An Unmanned Aerial Vehicle Platform. Applied Engineering in Agriculture. 25(6):803-809.

Zheng, X., Lan, Y., Zhu, J., Westbrook, J.K., Hoffmann, W.C., Lacey, R. 2009. Rapid identification of rice samples using an electronic nose. Journal of Bionics. 6:290-497.

Fritz, B.K., Hoffmann, W.C., Parker, C.T., Lopez, J. 2009. Development and testing of a laboratory spray table methodology to bioassay aerial spray drift. Journal of ASTM International. 6(6):Paper ID JAI102125.

Wang, X., Zheng, X., Lan, Y., Li, C., Shi, J., Xue, S.J. 2009. Application of response surface methodology to optimize microwave-assisted extraction of silymarin from milk thistle seeds. Separation and Purification Technology. 70:34-40.

Chang, S., Li, D., Lan, Y., Ozkan, N., Chen, X., Mao, Z. 2009. Study on creep properties of Japonica cooked rice and its relationship with rice chemical compositions and sensory evaluation. International Journal of Food Engineering. 5(3):Article 10.

Hoffmann, W.C., Walker, T., Fritz, B.K., Farooq, M., Smith, V., Robinson, C., Szumlas, D., Lan, Y. 2009. Spray characterization of ULV sprayers typically used in vector control. Journal of the American Mosquito Control Association. 25:332-337.

Fritz, B.K., Bagley, B., Hoffmann, W.C. 2010. Effects of spray mixtures on droplet size under aerial application conditions and implications on drift. Applied Engineering in Agriculture. 26:21-29.

Fritz, B.K., Lopez, J., Latheef, M.A., Martin, D.E., Hoffmann, W.C., Lan, Y. 2009. Aerial spray deposition on corn silks applied at high and low spray rates. International Agricultural Engineering Journal. 11:Manuscript 1360.

Gould, F., Blair, N.E., Reid, M., Lopez, J., Micinski, S. 2002. Bacillus thuringiensis-toxin resistance management: Stable isotope assessment of alternate host use by Helicoverpa zea. Proceedings of the National Academy of Sciences. 99:16581-16586.

Blanco, C.A., Teran-Vargas, A.P., Lopez, J., Kauffman, J.V. 2007. Naturally-occurring densities of Heliothis virescens and Helicoverpa zea (Lepidoptera: noctuidae) in three different plant hosts. Florida Entomologist. 90:742-750.

Zhang, H., Lan, Y., Lacey, R., Hoffmann, W.C., Huang, Y. 2009. Analysis of vegetation indices derived from aerial multispectral and ground hyperspectral data. International Journal of Agricultural and Biological Engineering. 2:1-8.

Zhang, H., Lan, Y., Lacey, R., Huang, Y., Hoffmann, W.C., Martin, D.E., Bora, G. 2009. Analysis of variograms with various sample sizes from a multispectral image. International Journal of Agricultural and Biological Engineering. 2:62-69.

Fritz, B.K., Hoffmann, W.C., Rohde, A., Warren, C., Faulkner, W. 2010. Simulating and characterizing agricultural ground applications for soil VOC deposition studies. Journal of ASTM International. 7(7):Paper ID JAI102776.

Hoffmann, W.C., Fritz, B.K., Martin, D.E., Atwood, R., Hurner, T., Ledebuhr, M., Tandy, M., Jackson, J., Wisler, G.C. 2010. Evaluation of low-volume sprayers used in asian citrus Psyllid control applications. HortTechnology. 20:632-639.

Last Modified: 06/22/2017
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