Aerial Application Technology for Sustainable Crop Production

Goals / Objectives
Objective 1: Optimize aerial spray technologies for on-target deposition and drift mitigation. Subobjective 1A: Characterize effects of spray systems and formulations on droplet size. Subobjective 1B: Enhance spray swath deposition and uniformity. Subobjective 1C: Develop criteria for efficient operation and selection of aerial spray systems. Objective 2: Develop geospatial data processing and analyses methods for crop condition assessment and pest management. Subobjective 2A: Develop variable rate application methods for plant growth regulators (PGRs) and defoliants based on physiological conditions. Subobjective 2B: Develop precision aerial application methods for fertilization and disease control based on biotic conditions.

Project Methods
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, on aerial application efficiency and biological efficacy. Efforts will focus on the integration of laboratory spray droplet measurements and remote sensing systems to maximize the efficacy of crop production materials while minimizing any off-target impact from these sprays. Plant health and species differences will be determined from remotely sensed data and used to make spray application decisions related to spatial locations and dosages. This project will develop and implement new and improved aerial application technologies for safe, efficient, and sustainable crop production and protection.

Progress 12/01/13 to 10/23/18

Outputs
Progress Report Objectives (from AD-416): Objective 1: Optimize aerial spray technologies for on-target deposition and drift mitigation. Subobjective 1A: Characterize effects of spray systems and formulations on droplet size. Subobjective 1B: Enhance spray swath deposition and uniformity. Subobjective 1C: Develop criteria for efficient operation and selection of aerial spray systems. Objective 2: Develop geospatial data processing and analyses methods for crop condition assessment and pest management. Subobjective 2A: Develop variable rate application methods for plant growth regulators (PGRs) and defoliants based on physiological conditions. Subobjective 2B: Develop precision aerial application methods for fertilization and disease control based on biotic conditions. 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, on aerial application efficiency and biological efficacy. Efforts will focus on the integration of laboratory spray droplet measurements and remote sensing systems to maximize the efficacy of crop production materials while minimizing any off-target impact from these sprays. Plant health and species differences will be determined from remotely sensed data and used to make spray application decisions related to spatial locations and dosages. This project will develop and implement new and improved aerial application technologies for safe, efficient, and sustainable crop production and protection. Work in FY 2018 made significant progress in improving aerial applications of crop production and protection materials in an effective manner. Spray atomization models were completed that allow applicators to properly set up their spray system to meet pesticide label requirements for droplet size and spray rate as well as account for the effects of tank mix adjuvants on spray deposition and drift reduction (Objective 1). Using the swath pattern string analysis system completed as part of this project, aerial spray systems were shown to maintain pattern uniformity and coverage while reducing drift with reductions in the effective spray boom width as this reduced spray entrainment in the wing tip vortices (Objective 1). Using readily available satellite imagery, prescription maps for site-specific control of cotton root rot were developed and shown to provide highly accurate identification of disease in impacted fields, and allow for more effective and economic treatments (Objective 2) . Improved image processing methods were developed to allow remotely sensed images that were once deemed unsuitable to be used to generate high quality maps for variable rate applications and field monitoring of crop health and pest conditions (Objective 2). These projects provide data for continued support to a number of collaborative partners including the EPA, agrochemical and spray equipment manufacturers, and the National Agricultural Aviation Association's annual aerial applicator training program. During the life of the project, the developed spray atomization models for agricultural aircraft were integrated into desktop computer and smartphone user interfaces and the technology transferred to applicators through technical session presentations and educational workshops (Objective 1). Novel aerial electrostatic spray application systems were shown to provide comparable control of spider mites in corn as that from conventional applications, allowing for increased operational efficiency (Objective 1). Remote sensing systems and image analysis methods for unmanned aerial platforms were developed to help growers assess crop germination status for timely replant and management decisions (Objective 2). Remote sensing data collected was paired with precision, variable rate applications of fungicide to develop and transfer best practice guidelines to cotton growers and crop consultants for effective site-specific management of cotton root rot (Objective 2). During the life of this project, assigned scientists served as experts for the aerial application industry and were sought out for advice and consultation by industry and academic research personnel, EPA partners, State Department, USDA-APHIS, and representatives from numerous state agencies and organizations. This project will expire in early FY 2019 and will be replaced by a bridging project which will continue the work until a new 5-year project plan is approved by the OSQR process. Accomplishments 01 Updating the USDA ARS rotary wing nozzle models. Successful aerial applications require proper selection and operational setup of the spray nozzle used to ensure that the spray droplet size meets both pesticide label requirements and site specific meteorological and geographical conditions. ARS scientists at College Station, Texas, successfully evaluated the 15 most commonly used helicopter and lower airspeed fixed-wing spray nozzles for droplet size across all potential nozzle configurations (nozzle size and position in the airstream) and operational settings (spray pressure and flight speed). The models significantly expand the currently available data for aerial application specific nozzles. The resulting droplet sizing models were added to the computer and mobile device based user-interfaces maintained by ARS. Using the developed droplet sizing models, aerial applicators can properly select the nozzle type and operational settings that ensure their spray applications meet agrochemical product label requirements to maximize efficacy with minimal off-target damage. 02 Integration of aerial imaging and variable rate technology for site- specific aerial herbicide application. As remote sensing and variable rate technology are becoming more available for aerial applicators, practical methodologies for effective integration of these technologies are needed for site-specific aerial applications of crop production and protection materials. ARS scientists at College Station, Texas, demonstrated how to integrate an airborne imaging system and a variable rate aerial application system for site-specific management of the winter weed, henbit. Results showed that the imaging system was effective for mapping henbit infestations and that the variable rate system could accurately deliver the product at the desired rate to the prescribed areas for effective control of the weed. The methodology and results from this study will be useful for aerial applicators to incorporate airborne imaging and variable rate application systems into their aerial application business to increase their capabilities and profits. 03 Aerial electrostatic spray deposition and canopy penetration in cotton. Many cotton insect pests reside on the underside of the leaves where it is difficult for traditional pesticide spray applications to reach. ARS scientists at College Station, Texas, explored the use of a novel aerial electrostatic spray technology to enhance spray penetration into a cotton canopy for increased deposition on plant surfaces. Results demonstrated that the use of aerial electrostatic spray application technologies, which operate at a third the normal application rate, provided equivalent spray deposition on top and bottom leaf surfaces as compared to conventional rotary nozzle applications, improving operational efficiency by the applicator while achieving equivalent pest control.

Impacts
(N/A)

Publications

Fritz, B.K., Hoffmann, W.C., Gizotti-De-Moraes, J., Guerrerio, M., Golus, J., Kruger, G. 2018. The impact of spray adjuvants on solution physical properties and spray droplet size. Journal of ASTM International. 37:22-32.
Zhang, J., Yang, C., Song, H., Hoffmann, W.C., Yeyin, S., Zhang, D., Zhang, G. 2017. Crop classification and LAI estimation using original and resolution-reduced images from consumer-grade cameras. Remote Sensing. 9(10):1-18.
Fritz, B.K., Hoffmann, W.C. 2017. Updating the USDA ARS rotary wing nozzle models. Applied Engineering in Agriculture. 33(5):631-640.
Wu, M., Yang, C., Song, X., Hoffmann, W.C., Huang, W., Niu, Z., Wang, C., Wang, L. 2018. Monitoring cotton root rot by synthetic Sentinel-2 NDVI time series using improved spatial and temporal data fusion. Scientific Reports. 8:1-12.
Martin, D.E., Latheef, M.A. 2018. Active optical sensor assessment of spider mite damage on greenhouse beans and cotton. Experimental and Applied Acarology. 74(2):147-158.
Zhou, Y., Boutton, T., Wu, B., Yang, C. 2017. Spatial heterogeneity of subsurface soil texture drives the landscape-scale pattern of woody patches in a subtropical savanna. Landscape Ecology. 32(4):915-929.
Chen, R., Chu, T., Landivar, J., Yang, C., Maeda, M. 2018. Monitoring cotton (Gossypium hirsutum L.) germination using ultrahigh-resolution UAS images. Precision Agriculture. 19(1):161-177.
Fritz, B.K., Hoffmann, W.C. 2016. Measuring spray droplet size from agricultural nozzles using laser diffraction. Journal of Visualized Experiments. doi:10.3791/54533.
Fritz, B.K., Czaczyk, Z., Hoffmann, W.C. 2016. Model based decision support system for agrochemical applications for MMAT nozzles. Journal of Plant Protection Research. 56(2):178-185.
Elsik, C., Fritz, B.K. 2015. Spray drift reduction test method correlation. Journal of ASTM International. doi:10.1520/STP157920130171.
Martin, D.E., Latheef, M.A. 2017. Efficacy of electrostatically-charged glyphosate on ryegrass. Journal of Electrostatics. 90:45-53.
Martin, D.E., Latheef, M.A. 2017. Remote sensing evaluation of two-spotted spider mite damage on greenhouse cotton. Journal of Visualized Experiments. doi:10.3791/54314.
Martin, D.E., Latheef, M.A. 2017. Aerial electrostatic spray deposition and canopy penetration in cotton. Journal of Electrostatics. 90:38-44.
Yang, C., Martin, D.E. 2017. Integration of aerial imaging and variable- rate technology for site-specific aerial herbicide application. Transactions of the ASABE. 60(3):635-644.
Song, X., Yang, C., Wu, M., Yang, G., Zhao, C., Hoffmann, W.C., Huang, W. 2017. Evaluation of Sentinel-2A satellite imagery for mapping cotton root rot. Remote Sensing. 9(9):1-17.
Katti, A.R., Lee, W., Ehsani, R., Yang, C., Mangan, R.L. 2015. Band selection using forward feature selection algorithm for citrus Huanglongbing disease detection. Biosystems Engineering. 40(4):417-427.
Hoffmann, W.C., Fritz, B.K., Gizotti-De-Moraes, J., Guerreiro De Jesus, M., Kruger, G. 2018. Determining water sensitive card spread factors for real world tank mixes. Journal of ASTM International.
Wang, X., Yang, C., Jian, Z., Song, H. 2018. Image dehazing based on dark channel prior and brightness enhancement for agricultural monitoring. International Journal of Agricultural and Biological Engineering. 11(2) :170-176.

Progress 10/01/16 to 09/30/17

Outputs
Progress Report Objectives (from AD-416): Objective 1: Optimize aerial spray technologies for on-target deposition and drift mitigation. Subobjective 1A: Characterize effects of spray systems and formulations on droplet size. Subobjective 1B: Enhance spray swath deposition and uniformity. Subobjective 1C: Develop criteria for efficient operation and selection of aerial spray systems. Objective 2: Develop geospatial data processing and analyses methods for crop condition assessment and pest management. Subobjective 2A: Develop variable rate application methods for plant growth regulators (PGRs) and defoliants based on physiological conditions. Subobjective 2B: Develop precision aerial application methods for fertilization and disease control based on biotic conditions. 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, on aerial application efficiency and biological efficacy. Efforts will focus on the integration of laboratory spray droplet measurements and remote sensing systems to maximize the efficacy of crop production materials while minimizing any off-target impact from these sprays. Plant health and species differences will be determined from remotely sensed data and used to make spray application decisions related to spatial locations and dosages. This project will develop and implement new and improved aerial application technologies for safe, efficient, and sustainable crop production and protection. Work under this project during FY 2017 resulted in significant progress in improving the effective use of crop production and protection materials, enhancing the use of remote sensing and precision application in crop production systems, and spray droplet modeling with an emphasis on rotary-wing aircraft models. Spray atomization models were completed for fixed and rotary wing aircraft and the smartphone app was updated (Objective 1). Significant progress was made in development of spray deposition and drift models, which will aid spray applicators in making spray applications that increase efficacy and minimize off-target spray drift. Wind-tunnel tests were completed to determine the levels of spray drift mitigation from a number of spray nozzles and formulations including real-world tank mixes used by aerial applicators and public health users (Objective 1). To control cotton root rot, a variable-rate fungicide applicator was installed on a cooperator�s planter. The applicator only applied fungicide in the areas of the field where root rot had been identified resulting in significant cost saving through reduced application rates of the fungicide (Objective 2). Remote sensing studies were conducted that identified volunteer cotton plants in ditches and waterways, and diseased cotton plants; the data from these flights was coupled with prescription application maps to regulate the usage of agrochemicals based on field conditions (Objective 2). Numerous remote sensing flights were conducted to monitor the spread of cotton root rot at two locations in Texas. A dual-camera imaging system for remote sensing studies was developed using a consumer-grade camera and transferred to aerial applicators to use in their operations (Objective 2) . These projects support the DoD-Deployed WarFighter Protection Program with specific collaborations with the U.S. Navy Entomology Center of Excellence, EPA Drift Reduction Technology Program, several agrochemical companies, and equipment manufacturers. Project scientists during FY 2017 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, Department of Homeland Security, Department of Defense, State Department, USDA-APHIS, and representatives from numerous state agencies and organizations. This project supports National Programs 305, 304, and 104. Accomplishments 01 Early identification of cotton fields using mosaicked aerial multispectral imagery. Early identification of cotton fields is important for advancing boll weevil eradication progress and reducing the risk of reinfestation. Remote sensing has long been used for crop identification, but limited work has been reported on early identification of cotton fields. ARS scientists at College Station, Texas, evaluated aerial imagery for identifying cotton fields before cotton plants start to bloom. Aerial color and near-infrared images taken over an 8 km by 12 km cropping area were mosaicked and then classified into different crops and cover types using image classification techniques. Results showed that classification maps were able to correctly identify over 90% of the cotton areas. The methodologies presented in this study will be useful for boll weevil eradication program managers to quickly and efficiently identify cotton fields at relatively early growth stages using mosaicked aerial imagery. 02 Standardized methods to evaluate agricultural spray nozzles for droplet size. Any successful agrochemical application starts with understanding the role that nozzle type and operational setup play in creating the applied droplet size. With a number of testing methods and instruments available for these evaluations, standard methods are critical to ensure that consistent, repeatable results are obtained. Standardized methods, shown to minimize sampling bias and provide reliable results, were developed by ARS researchers at College Station, Texas, and were reported as part of a novel publication outlet devoted to documentation of scientific experimental methods through both written and video media. Reporting and demonstrating the standard methods provide a significant record of guidance for other research personnel and locations conducting research related to agrochemical spray applications. These standard methods currently provide the basis for a number of national and international programs and standards, including the EPA Drift Reduction Technology Program and standards from the American Society of Agricultural and Biological Engineers, American Society for Testing and Materials International, and the International Standards Organization.

Impacts
(N/A)

Publications

Fritz, B.K., Hoffmann, W.C., Henry, R. 2016. The effect of adjuvants at high spray pressures for aerial applications. American Society for Testing and Materials. doi:10.1520/STP159520150086.
Thistle, H., Reardon, R., Bonds, J., Fritz, B.K., Hoffmann, W.C., Kees, G., Grob, I., Hewitt, A., O'Donnell, C., Onken, B. 2016. Aerially released spray penetration of a tall coniferous canopy. Transactions of the ASABE. 59(5):1221-1231.
Yang, C., Suh, C.P., Westbrook, J.K. 2017. Early identification of cotton fields using mosaicked aerial multispectral imagery. Journal of Applied Remote Sensing (JARS). 11(1):016008.
Chu, T., Chen, R., Landivar, J., Maeda, M., Yang, C., Starek, M. 2016. Cotton growth modeling and assessment using UAS visual-band imagery. Journal of Applied Remote Sensing (JARS). 10(3):036018.
Shi, Y., Thomasson, A., Murray, S., Pugh, N.A., Rooney, W.L., Shafian, S., Rajan, N., Rouze, G., Morgan, C.L., Neely, H.L., Rana, A., Bagavathiannan, M.V., Henrickson, J., Bowden, E., Valasek, J., Olsenholler, J., Bishop, M. P., Sheridan, R., Putman, E.B., Popescu, S., Burks, T., Cope, D., Ibrahim, A., McCutchen, B.F., Baltensperger, D.D., Avant, R.V., Vidrine, M., Yang, C. 2016. Unmanned aerial vehicles for high-throughput phenotyping and agronomic research. PLoS One. 11(7):e0159781.
Wu, M., Yang, C., Song, X., Hoffmann, W.C., Huang, W., Niu, Z., Wang, C., Wang, L. 2017. Evaluation of orthomosics and digital surface models derived from aerial imagery for crop mapping. Remote Sensing. doi:10.3390/ rs9030239.
Henry, R., Fritz, B.K., Hoffmann, W.C., Kruger, G. 2016. The influence of nozzle type, operating pressure, and tank-mixture components on droplet characteristics and the EPA's drift reduction rating. Journal of ASTM International. doi:10.1520/STP159520150098.
Thistle, H.W., Bonds, J.S., Kees, G.J., Fritz, B.K. 2017. Evaluation of spray drift from backpack and UTV spraying. Transactions of the ASABE. 60(1):41-50.
Westbrook, J.K., Eyster, R.S., Yang, C., Suh, C.P. 2016. Airborne multispectral identification of individual cotton plants using consumer- grade cameras. Remote Sensing Applications: Society and Environment. 4:37- 43.
Lan, Y., Chen, S., Fritz, B.K. 2017. Current status and future trends of precision agricultural aviation technologies. International Journal of Agricultural and Biological Engineering. 10(3):1-17.
Fisher, A., Coleman, C., Hoffmann, W.C., Fritz, B.K., Rangel, J. 2017. The synergistic effects of almond protection fungicides on honey bee (Apis mellifera) forager survival. Journal of Economic Entomology. 110(3):802- 808.
Song, X., Yang, G., Yang, C., Wang, J., Cui, B. 2017. Spatial variability analysis of within-field winter wheat nitrogen and grain quality using canopy fluorescence sensor measurements. Remote Sensing. 9:237.

Progress 10/01/15 to 09/30/16

Outputs
Progress Report Objectives (from AD-416): Objective 1: Optimize aerial spray technologies for on-target deposition and drift mitigation. Subobjective 1A: Characterize effects of spray systems and formulations on droplet size. Subobjective 1B: Enhance spray swath deposition and uniformity. Subobjective 1C: Develop criteria for efficient operation and selection of aerial spray systems. Objective 2: Develop geospatial data processing and analyses methods for crop condition assessment and pest management. Subobjective 2A: Develop variable rate application methods for plant growth regulators (PGRs) and defoliants based on physiological conditions. Subobjective 2B: Develop precision aerial application methods for fertilization and disease control based on biotic conditions. 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, on aerial application efficiency and biological efficacy. Efforts will focus on the integration of laboratory spray droplet measurements and remote sensing systems to maximize the efficacy of crop production materials while minimizing any off-target impact from these sprays. Plant health and species differences will be determined from remotely sensed data and used to make spray application decisions related to spatial locations and dosages. This project will develop and implement new and improved aerial application technologies for safe, efficient, and sustainable crop production and protection. Work under this project during FY 2016 resulted in significant progress in improving the effective use of crop production and protection materials, enhancing the use of remote sensing and precision application in crop production systems, and spray droplet modeling with an emphasis on rotary-wing aircraft models. Significant progress was made in development of spray deposition and drift models, which will aid spray applicators in making spray applications that increase efficacy and minimize off-target spray drift. Wind-tunnel tests were completed to determine the levels of spray drift mitigation from a number of spray nozzles and formulations including real-world tank mixes used by aerial applicators. A variable-rate controller was installed and is currently under field usage for screwworm dispersion with the APHIS-Screwworm Barrier Maintenance Program in Panama. Free smartphone applications along with the Unit�s spray atomization models were further developed and modified for the iPhone platforms that transfer the project�s research data into more useful formats for our customers. Remote sensing studies were conducted that identified volunteer cotton plants in ditches and waterways, and diseased cotton plants. The data from these flights was coupled with prescription application maps to regulate the usage of agrochemicals based on field conditions. Numerous remote sensing flights were conducted to monitor the spread of cotton root rot at two locations in Texas. A dual-camera imaging system for remote sensing studies was developed using a consumer-grade camera and transferred to aerial applicators to use in their operations. These projects support the DoD- Deployed WarFighter Protection Program with specific collaborations with the U.S. Navy Entomology Center of Excellence, EPA Drift Reduction Technology (DRT) Program, several agrochemical companies, and equipment manufacturers. Project scientists during FY 2016 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, Department of Homeland Security, Department of Defense, State Department, USDA-APHIS, and representatives from numerous state agencies and organizations. This project supports National Programs 305, 304, and 104. Accomplishments 01 Applying droplet sizing calculators to optimize aerial applications. Successful aerial applications start with proper spray nozzle selection, setup and operation to ensure the resulting droplet size meets both pesticide product label requirements and meteorological and geographical conditions at the site of application. Recent computational droplet sizing models developed by ARS researchers at College Station, Texas, were adapted to a visual interface for use by applicators when making nozzle selections and operational decisions. Using the computational models, graphical representations of each nozzle's full operational spectrum were developed with droplet size classification data visually represented for quick and ready interpretation and selection. The new graphical interfaces greatly enhance the usability of the aerial nozzle droplet sizing models, thus allowing applicators to more quickly make operational decisions and document application parameters in order to meet pesticide product labels and ultimately optimize applications. 02 Consumer-grade cameras for aerial application. Consumer-grade cameras have been increasingly used in scientific research and remote sensing applications because of their low cost and ease of use. ARS researchers at College Station, Texas, assembled two imaging systems consisting of consumer-grade cameras for use on agricultural aircraft. They evaluated imagery acquired by the systems over a large cropping area for crop identification and assessment and compared different image mosaicking techniques for image stitching. Image classification and accuracy assessment showed that both normal color and near-infrared imagery acquired by the systems was useful for crop identification and crop growth assessment. The results from this study have provided useful information for aerial applicators and other remote sensing practitioners on the use of consumer-grade cameras. More than 20 aerial applicators have shown strong interest in assembling and using these cameras in their operations.

Impacts
(N/A)

Publications

Fritz, B.K., Hoffmann, W.C., Anderson, J. 2016. Response surface method for evaluation of the performance of agricultural application spray nozzles. Pesticide Formulation and Delivery Systems: 35th Volume, American Society for Testing and Materials STP1587, G.R. Goss, ed., ASTM International, West Conshohocken, PA. pp. 61-76. doi:10.1520/ STP158720140100.
Fritz, B.K., Hoffmann, W.C., Bretthauer, S. 2016. A practical interpretation and use of the USDA aerial fixed-wing nozzle models. Applied Engineering in Agriculture. 32(1):29-35.
Creech, C., Henry, R., Fritz, B.K., Kruger, G. 2015. Influence of herbicide active ingredient, nozzle type, orifice size, spray pressure, and carrier volume rate on spray droplet size characteristics. Weed Technology. 29(2):298-310.
Farooq, M., Hoffmann, W.C., Fritz, B.K., Cote, N., Walker, T., Smith, V. 2016. Evaluation of spray droplet spectrum of sprayers used for vector control. Atomization and Sprays. 26(8):739-754.
Toose, L., Warren, C., Mackay, D., Pinkerton, T., Letinski, D., Manning, R. , Connelly, M., Rohde, A., Fritz, B.K., Hoffmann, W.C. 2015. Assessing the fate of an aromatic hydrocarbon fluid in agricultural spray applications using the three-stage ADVOCATE model framework. Journal of Agricultural and Food Chemistry. 63(31):6866-6875.
Song, H., Yang, C., Zhang, J., Hoffmann, W.C., He, D., Thomasson, A. 2016. Comparison of mosaicking techniques for airborne images from consumer- grade cameras. Journal of Applied Remote Sensing (JARS). 10:016030.
Zhang, J., Yang, C., Song, H., Hoffmann, W.C., Zhang, D., Zhang, G. 2016. Evaluation of an airborne remote sensing platform consisting of two consumer-grade cameras for crop identification. Remote Sensing. 8:257.
Yang, C., Sui, R., Lee, W. 2016. Precision agriculture in large-scale mechanized farming. In: Zhang, Q., ed., Precision Agriculture Technology for Crop Farming. CRC Press, Boca Raton, FL. p. 177-211.
Yang, C., Odvody, G., Thomasson, J., Isakeit, T., Nichols, R. 2016. Change detection of cotton root rot infection over a 10-year interval using airborne multispectral imagery. Computers and Electronics in Agriculture. 123:154-162.
Song, H., Yang, C., Zhang, J., He, D., Thomasson, J.A. 2015. Combining fuzzy set theory and nonlinear stretching enhancement for unsupervised classification of cotton root rot. Journal of Applied Remote Sensing (JARS) . 9:096013.
Cribben, C.D., Thomasson, J.A., Ge, Y., Morgan, C.S., Yang, C., Isakeit, T. , Nichols, R.L. 2016. Site-specific relationships between cotton root rot and soil properties. Journal of Cotton Science. 20:67-75.
Hoffmann, W.C., Fritz, B.K., Yang, C. 2016. Effects of Spray Adjuvants on Spray Droplet Size from a Rotary Atomizer. American Society for Testing and Materials. 35:52-60. doi:10.1520/STP1587201400992.

Progress 10/01/14 to 09/30/15

Outputs
Progress Report Objectives (from AD-416): Objective 1: Optimize aerial spray technologies for on-target deposition and drift mitigation. Subobjective 1A: Characterize effects of spray systems and formulations on droplet size. Subobjective 1B: Enhance spray swath deposition and uniformity. Subobjective 1C: Develop criteria for efficient operation and selection of aerial spray systems. Objective 2: Develop geospatial data processing and analyses methods for crop condition assessment and pest management. Subobjective 2A: Develop variable rate application methods for plant growth regulators (PGRs) and defoliants based on physiological conditions. Subobjective 2B: Develop precision aerial application methods for fertilization and disease control based on biotic conditions. 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, on aerial application efficiency and biological efficacy. Efforts will focus on the integration of laboratory spray droplet measurements and remote sensing systems to maximize the efficacy of crop production materials while minimizing any off-target impact from these sprays. Plant health and species differences will be determined from remotely sensed data and used to make spray application decisions related to spatial locations and dosages. This project will develop and implement new and improved aerial application technologies for safe, efficient, and sustainable crop production and protection. Work under this project during FY 2015 resulted in significant progress in improving the efficacy of crop production and protection materials (Objective 1), enhancing the use of remote sensing and precision application in crop production systems (Objective 2), and spray droplet modeling (Objectives 1, 2). Significant progress was made in development of spray deposition and drift models, which will aid spray applicators in making spray applications that increase efficacy and minimize off-target spray drift. Wind-tunnel tests were completed to determine the levels of spray drift mitigation from a number of spray nozzles and formulations including real-world tank mixes used by aerial applicators. These projects support the EPA Drift Reduction Technology Program, DoD-Deployed WarFighter Protection Program, and U.S. Navy Entomology Center of Excellence. A variable-rate controller was developed and installed for screwworm dispersion with the APHIS-Screwworm Barrier Maintenance Program in Panama. Biological assessments of various mosquito control products and rates were conducted in conjunction with university and mosquito abatement personnel. These studies also included numerous honeybee toxicity studies. Free smartphone applications along with the Unit�s spray atomization models were further developed and modified for the iPhone and Google Play platforms that transfer the project�s research data into more useful formats for our customers. Remote sensing studies were conducted that identified volunteer cotton plants in ditches and waterways, and diseased cotton plants. Numerous remote sensing flights were conducted to monitor the spread of cotton root rot at two locations in Texas. A single camera imaging system for remote sensing studies was developed using a consumer-grade camera and transferred to aerial applicators to use in their operations. Project scientists during FY 2015 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, Department of Homeland Security, DoD, State Department, USDA-APHIS, and representatives from numerous state agencies and organizations. This project supports National Programs 305, 304, and 104. Accomplishments 01 A low-cost single-camera imaging system for aerial applicators. Agricultural aircraft provide a readily available and versatile platform for airborne remote sensing. ARS researchers at College Station, Texas, developed a low-cost, user-friendly imaging system that can be easily installed on aerial applicators� aircraft for pest detection and application assessment. The system employs a digital camera to acquire geotagged images and multiple images can be easily stitched together using readily available software for assessing large cropping areas. Aerial applicators can use the procedures and techniques developed by this work to assemble such a system and use it to generate additional revenues from remote sensing services. 02 Update to the ARS fixed wing spray nozzle models. Successful aerial applications require proper spray nozzle selection and setup to insure droplet size meets both label requirements and meteorological and geographical conditions at the site of application. ARS scientists at College Station, Texas, successfully evaluated the 12 most commonly used aerial spray nozzles for droplet size across all potential nozzle configurations (nozzle size and position in the airstream) and operational settings (spray pressure and flight speed). The new models greatly enhance the currently available data for the aerial nozzles tested and were used to update computer and mobile device based user interfaces. Using the developed spray nozzle models, aerial applicators can properly select nozzle type and operational settings that insure their applications meet agrochemical product label requirements to maximize efficacy with minimal off-target drift. 03 Assessment of spider mite damage via multispectral imaging. Spider mites can cause significant damage in cotton, resulting in significantly decreased yields. ARS researchers at College Station, Texas, used a multispectral optical sensor to quantify spider mite damage in cotton, showing that half-rate application of common acaracides was just as effective as full-rate applications in controlling mites. Farmers, crop consultants, and applicators will be able to use the results of this work to reduce chemical usage and environmental loading while maintaining good control of these cotton pests. 04 Spray adjuvants minimally affect droplet size with rotary atomizers. Rotary atomizers are a type of spray nozzle used by applicators in a variety of spray applications, including forestry sprays and mosquito abatement. ARS researchers at College Station, Texas, conducted a series of fungicide spray atomization trials to determine the effects of spray adjuvants, which can change the physical properties of a spray solution, on spray droplet size from a rotary atomizer. The different adjuvants affected droplet by less than 10 percent as compared to the fungicide only spray solution. Understanding the role different adjuvant types play in the final droplet size of the spray is key to successfully setting up and making effective, environmentally sensitive applications with rotary atomizers.

Impacts
(N/A)

Publications

Fritz, B.K., Hoffmann, W.C., Bonds, J., Haas, K., Zbigniew, C. 2014. The biological effect of cage design corrected for reductions in spray penetration. Journal of Plant Protection Research. 54(4):395-400.
Martin, D.E., Latheef, M.A., Lopez, J. 2015. Evaluation of selected acaricides against two-spotted spider mite (Acari: Tetranychidae) on greenhouse cotton using multispectral data. Experimental and Applied Acarology. 66(2):227-245.
Villar, J.L., Turland, N.J., Juan, A., Gaskin, J.F., Alonso, M.A., Crespo, M.B. 2015. Tamarix minoa (Tamaricaceae), a new species from the island of Crete (Greece) based on morphological and plastid molecular sequence data. Taxon. 45(2):161-172. DOI: 10.3372/wi.45.45201.
Hoffmann, W.C., Fritz, B.K., Farooq, M., Walker, T., Hornsby, J., Bond, J. 2013. Evaluation of aerial spray technologies for adult mosquito control applications. Journal of Plant Protection Research. 53:222-29.
Henry, R., Kruger, G., Fritz, B.K., Hoffmann, W.C., Bagley, B., Czazyck, Z. 2014. Measuring the effect of spray plume angle on the accuracy of droplet size data. In: Sesa, C., editor. Pesticide Formulation and Delivery Systems: 33rd Volume, "Sustainability: Contributions from Formulation Technology." West Conshohocken, PA: ASTM International. p. 129- 138. DOI: 10.1520/STP1569-EB.
Huang, Y., Thomson, S.J., Hoffman, W.C., Lan, Y., Fritz, B.K. 2013. Development and prospect of unmanned aerial vehicles for agricultural production management. International Journal of Agricultural and Biological Engineering. 6(3):1-10.
Latheef, M.A., Hoffmann, W.C. 2014. Toxicity of selected acaricides in a glass-vial bioassay to two-spotted spider mite (Acari: Tetranychidae). Southwestern Entomologist. 39(1):29-36.
Yang, C., Hoffmann, W.C. 2015. A low-cost single-camera imaging system for aerial applicators. Journal of Applied Remote Sensing (JARS). 9:096064.
Fritz, B.K., Hoffmann, W.C. 2015. Update to the USDA-ARS fixed-wing spray nozzle models. Transactions of the ASABE. 58(2):281-295.
Lopez, J., Latheef, M.A., Hoffmann, W.C. 2014. A multiyear study on seasonal flight activity based on captures of southern green stink bug (Hemiptera: Pentatomidae) in blacklight traps in Central Texas. Journal of Cotton Science. 18:153-165.
Zhang, D., Chen, L., Zhang, R., Xu, G., Lan, Y., Hoffmann, W.C., Wang, X., Xu, M. 2015. Evaluating effective swath width and droplet distribution of aerial spraying systems on M-18B and Thrush 510G airplanes. International Journal of Agricultural and Biological Engineering. 8(2):21-30.
Martin, D.E., Lopez, J., Lan, Y. 2012. Laboratory evaluation of the GreenSeeker (TM) hand-held optical sensor to variations in orientation and height above canopy. International Journal of Agricultural and Biological Engineering. 5(1):43-47.
Suh, C.P., Medrano, E.G., Lan, Y. 2015. Detecting cotton boll rot with an electronic nose. Journal of Cotton Science. 18:435-443.
Liu, Y., Wan, C., Hao, Y., Lan, Y. 2013. Rapid quantitative analysis of Dimethoate pesticide using surface enhanced raman spectroscopy. Food and Bioprocess Technology. 56:1043-1049.
Westbrook, J.K., Suh, C.P., Yang, C., Lan, Y., Eyster, R.S. 2015. Airborne multispectral detection of regrowth cotton fields. Journal of Applied Remote Sensing (JARS). 9(1):096081.
Yang, F., Liu, S., Chen, L., Song, H., Wang, Y., Lan, Y. 2012. Detection method of various obstacles in farmland based on stereovision technology. Transactions of the Chinese Agricultural Machinery. 43(5):168-172.
Martin, D.E. 2013. Flow variability of an aerial variable-rate nozzle at constant pressures. Applied Engineering in Agriculture. 29:483-488.
Martin, D.E., Carlton, J.B. 2013. Airspeed and orifice size affect spray droplet spectra from an aerial electrostatic nozzle for rotary-wing applications. Atomization and Sprays. 22:997-1010.
Yang, C., Everitt, J.H., Du, Q., Luo, B., Chanussot, J. 2013. Using high resolution airborne and satellite imagery to assess crop growth and yield variability for precision agriculture. Proceedings of the Institute of Electrical and Electronics Engineers. 101:582-592.
Yang, C., Odvody, G.N., Fernandez, C.J., Landivar, J.A., Minzenmayer, R.R., Nichols, R.L. 2015. Evaluating unsupervised and supervised image classification methods for mapping cotton root rot. Precision Agriculture. 16:201-215.
Everitt, J.H., Yang, C., Summy, K.R., Owens, C.S., Glomski, L.M., Smart, R. M. 2011. Using in situ hyperspectral reflectance data to distinquish nine aquatic plant species. Geocarto International. 26(6):459-473.
Luo, B., Yang, C., Chanussot, J. 2013. Crop yield estimation based on unsupervised linear unmixing of multidate hyperspectral imagery. IEEE Transactions on Geoscience and Remote Sensing. 51:162-173.
Moran, P.J., Yang, C. 2012. Distribution of wild taro (Colocasia esculenta) in subtropical Texas, growth of young colonies, and tolerance to simulated herbivory. Subtropical Plant Science. 64:18-28.
Everitt, J.H., Yang, C., Summy, K.R., Nachtrieb, J.G. 2013. Using hyperspectral reflectance data to assess biocontrol damage to giant salvinia. Geocarto International. 28(6):502-516.
Ran, Q., Li, W., Du, Q., Yang, C. 2015. Hyperspectral image classification for mapping agricultural tillage practices. Journal of Applied Remote Sensing (JARS). 9:097298.
Everitt, J.H., Summy, K.R., Glomski, L.M., Owens, C.S., Yang, C. 2009. Spectral reflectance and digital image relations among five aquatic weeds. Geocarto International. 61:15-23.
Li, H., Lee, W., Wang, K., Ehsani, R., Yang, C. 2014. Extended spectral angle mapping (ESAM) for citrus greening disease detection using airborne hyperspectral imaging. Precision Agriculture. 15:162-183.
Li, X., Lee, W., Li, M., Ehsani, R., Mishra, A., Yang, C. 2015. Feasibility study on Huanglongbing (citrus greening) detection based on WorldView-2 satellite imagery. Biosystems Engineering. 132:28-38.

Progress 10/01/13 to 09/30/14

Outputs
Progress Report Objectives (from AD-416): Objective 1: Optimize aerial spray technologies for on-target deposition and drift mitigation. Subobjective 1A: Characterize effects of spray systems and formulations on droplet size. Subobjective 1B: Enhance spray swath deposition and uniformity. Subobjective 1C: Develop criteria for efficient operation and selection of aerial spray systems. Objective 2: Develop geospatial data processing and analyses methods for crop condition assessment and pest management. Subobjective 2A: Develop variable rate application methods for plant growth regulators (PGRs) and defoliants based on physiological conditions. Subobjective 2B: Develop precision aerial application methods for fertilization and disease control based on biotic conditions. 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, on aerial application efficiency and biological efficacy. Efforts will focus on the integration of laboratory spray droplet measurements and remote sensing systems to maximize the efficacy of crop production materials while minimizing any off-target impact from these sprays. Plant health and species differences will be determined from remotely sensed data and used to make spray application decisions related to spatial locations and dosages. This project will develop and implement new and improved aerial application technologies for safe, efficient, and sustainable crop production and protection. Work under this project during FY 2014 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 modeling. 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, including real-world tank mixes used by aerial applicators. These projects support the EPA Drift Reduction Technology (DRT) Program, DoD- Deployed WarFighter Protection Program, APHIS-Screwworm Barrier Maintenance Program in Panama, and U.S. Navy Entomology Center of Excellence. Biological assessments of various mosquito control products and rates were conducted in new wind tunnel trials and included honeybee toxicity studies. Free smartphone applications were further developed and modified for the iPhone and Google Play platforms that transfer the project's research data into more useful formats for our customers. Remote sensing studies were conducted that identified volunteer cotton plants in ditches and waterways, and diseased cotton plants. Numerous remote sensing flights were conducted to monitor the spread of cotton root rot at two locations in Texas. Both aerial and ground remote sensing studies were conducted to evaluate nitrogen deficiencies in corn and disease severity in rice. A two-camera imaging system for remote sensing studies was developed using consumer-grade cameras and proved to be a good alternative to more expensive camera systems. Significant progress was made in development of spray deposition and drift models, which will aid spray applicators in making spray applications that increase efficacy and minimize off-target spray drift. Project scientists during FY 2014 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, Department of Homeland Security, Department of Defense, State Department, USDA-APHIS, and representatives from numerous state agencies and organizations. This project successfully passed a program review by OSQR in 2014 and supports National Programs 305, 304, and 104. Accomplishments 01 Spray adjuvants and airspeed affect droplet size for real world tank mixes. A multitude of data exists detailing the role that either the spray adjuvant or the speed of the aircraft play in atomization of the spray cloud, but little of the research explores how spray droplet size is impacted as both of these factors change. ARS researchers at College Station, Texas, evaluated seven different types of spray adjuvants added to a real-world herbicide tank mix across the full spectrum of fixed-wing aircraft operational speeds for two typical aerial spray nozzles. The objective of the work was to develop a better understanding of how airspeed and adjuvant type work together to influence the resulting spray droplet size. Following standardized testing methods, the work showed that each adjuvant type behaved differently for each nozzle and across the range of airspeeds tested, and that at maximum airspeed the atomization of the spray cloud is dominated by breakup due to airshear with little adjuvant effect. This work has greatly improved understanding of the role adjuvants play in manipulating droplet size in aerial application scenarios, demonstrating that selecting the proper nozzle and application airspeed are critical to optimizing the spray quality of an application. 02 An airborne two-camera imaging system for agricultural remote sensing. Recent advances in imaging technologies have made consumer-grade digital cameras an attractive option for remote sensing due to their low cost, compact size, and user-friendliness. ARS researchers at College Station, Texas, assembled and evaluated an airborne multispectral imaging system based on two identical consumer-grade Canon cameras. One camera captures normal color images while the other obtains near-infrared images with filtering techniques. The color camera is also equipped with a GPS receiver to allow images to be geotagged; a remote control is used to trigger both cameras simultaneously. Geotagged images from the system can be viewed on any image viewer and on Google Earth for quick assessment prior to digital image analysis. The imaging system was tested under various flight and land cover conditions; optimal camera settings were determined for airborne image acquisition. Analysis of example images established that this system has good potential for crop condition assessment, pest detection, precision aerial application, and other agricultural applications. 03 Development of new tracer dye for agricultural sprays. Spray application researchers commonly use tracer dyes to measure the movement of agricultural sprays from the sprayer to the intended targets. These dyes allow quantification of spray deposition and drift without having to use potentially toxic active ingredients that would increase exposure risks to involved personnel. ARS researchers at College Station, Texas, evaluated a new tracer dye, abbreviated as PTSA, and found it to be highly soluble in the spray solution, stable in sunlight, and recoverable from plant and artificial surfaces. The PTSA dye is a significant improvement over dyes currently in use, and opens up a new set of methodologies that applicators and researchers can use in their spray application research studies. 04 Fluorescent imaging technique for quantifying spray deposits on plant leaves. Conventional agricultural insecticide sprays may be ineffective when specific crop pest insects live and feed on the underside of plant leaves. Although electrical charging of these sprays increases the amount of insecticide material that deposits on the underside of leaves, new techniques are needed for measuring droplet deposition on the underside of leaves. ARS researchers at College Station, Texas, developed a new measurement technique using image acquisition of spray droplets mixed with fluorescent dye, and image processing and analysis using readily-available software. Important results from the analysis include the quantity, size, and coverage area of droplets on the leaf. This spray droplet measurement technique will help agricultural applicators accurately assess and improve precision spray applications for effective control of pest insects.

Impacts
(N/A)

Publications

Fritz, B.K., Hoffmann, W.C., Bagley, W.E., Kruger, G., Czaczyk, Z., Henry, R. 2014. Inflence of air shear and adjuvants on spray atomization. In: Sesa, C., editor. Pesticide Formulation and Delivery Systems: 33rd Volume, Sustainability: Contributions from Formulation Technology, STP 1569. ASTM International: West Conshohocken, PA. p. 139-150. doi: 10.1520/ STP156920120131.
Fritz, B.K., Hoffmann, W.C., Kruger, G., Henry, R., Hewitt, A., Czaczyk, Z. 2014. Comparison of drop size data from ground and aerial application nozzles at three testing laboratories. Atomization and Sprays. 24(2):181- 192.
Hoffmann, W.C., Fritz, B.K., Bagley, W.E., Kruger, G., Henry, R., Czaczyk, Z. 2014. Effects of nozzle spray angle on droplet size and velocity. In: Sesa, C., editor. Pesticide Formulation and Delivery Systems: 33rd Volume, Sustainability: Contributions from Formulation Technology, STP 1569. ASTM International: West Conshohocken, PA. p. 151-173. doi: 10.1520/ STP156920120131.
Hoffmann, W.C., Fritz, B.K., Ledebuhr, M. 2014. Evaluation of 1, 3, 6, 8- pyrene tetra sulfonic acid tetra sodium salt (PTSA) as an agricultural spray tracer dye. Applied Engineering in Agriculture. 30(1):25-28.
Yang, C., Westbrook, J.K., Suh, C.P., Martin, D.E., Hoffmann, W.C., Lan, Y. , Fritz, B.K., Goolsby, J. 2014. An airborne multispectral imaging system based on two consumer-grade cameras for agricultural remote sensing. Remote Sensing. 6:5257-5278.
Lopez, J., Latheef, M.A., Hoffmann, W.C. 2014. Toxicity and feeding response of adult corn earworm (Lepidoptera: Noctuidae) to an organic spinosad formulation in sucrose solution. Pest Management Science. 2(1):33- 41.
Xue, X., Tu, K., Lan, Y. 2013. Effects of pesticides aerial applications on rice quality. Transactions of the Chinese Society for Agricultural Machinery. 44(12):94-98.
Martin, D.E. 2014. A fluorescent imaging technique for quantifying spray deposits on plant leaves. Atomization and Sprays. 24(4):367-373.
Yang, C., Odvody, G.N., Fernandez, C.J., Landivar, J.A., Minzenmayer, R.R., Nichols, R.L., Thomasson, J.A. 2014. Monitoring cotton root rot progression within a growing season using airborne multispectral imagery. Journal of Cotton Science. 18:85-94.
Fritz, B.K., Hoffmann, W.C., Bagley, W.E., Kruger, G., Czaczyk, Z., Henry, R. 2014. Measuring droplet size of agriuclutral spray nozzles - Measurement distance and airspeed effects. Atomization and Sprays. 24(9) :747-760.