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The primary objective of this project is to evaluate nozzle performance, both selection and usage, and with the inclusion of spray adjuvants. The goal will be to create recommendations for various application scenarios common to agriculture in Illinois, both aerial and ground, that maximize efficacy while minimizing drift. The following individual projects are planned to meet this objective: <ul> <LI>Evaluation of various adjuvants for efficacy and drift control for low volume aerial applications of fungicides on corn. Adjuvants to be tested include deposition aids, surfactants, crop oils, and others. <LI> An investigation of how various pesticides and adjuvants impact the spray droplet size and pattern uniformity for aerial applications. Pesticides will primarily be foliar fungicides commonly applied to corn in Illinois. Adjuvants to be tested include deposition aids, surfactants, crop oils, and others. <LI>A study to determine how swath width, application height, and weather factors impact the uniformity of low volume aerial applications on corn. The spray patterns will be measured using a monofilament line strung through a corn field at ear height. <LI>Measuring the differences in efficacy and drift reduction of various nozzle types used in aerial application.<LI> Comparing the efficacy of a low volume aerial application and a high volume ground application. <LI>Determining the impact the use of automatic spray rate controllers has on spray droplet spectrum and application uniformity. Popular nozzle types and sizes will be examined at pressures throughout their pressure range to determine how the droplet size and pattern width changes and the pressure increases.<LI>Study to determine the impact various pesticides, deposition aids, and surfactants have on the spray droplet spectrum of popular ground application nozzles.
Non-Technical Summary: In order to optimize sprayer performance both efficacy and drift need to be considered. Many applicators, particularly aerial, are looking to reduce their application volumes to increase their productivity. In addition, many of the pesticides currently used in crop protection are contact or locally systemic products. These products require increased coverage in order to be effective. Lower spray application volumes and less systemic pesticides both require the use of smaller droplet sizes in order to maintain efficacy. Even systemic products have experienced efficacy issues in recent years, likely because of poor coverage and deposition associated with the use of large drift-resistant droplets. Due to glyphosate resistant weeds, dicamba and 2,4-D resistant crops are expected to be commercially available within the next several years. These two herbicides will likely require a smaller droplet size then glyphosate in order to be effective. The need for a smaller droplet spectrum to provide effective coverage will increase the risk of these products drifting off target. Benefits of low volume aerial applications include increased productivity and timelier applications. Foliar fungicide applications to corn and soybeans, insecticide applications to treat soybean aphids, and applications to control Asian soybean rust, are all applications that need to be made at the correct time. With millions of acres of both corn and soybeans potentially needing to be treated in a short time period, the ability to make low volume applications is critical. For low volume applications, it becomes more difficult to balance efficacy with drift reduction. Knowing what droplet size is required for an application and then properly setting up the application equipment to provide this droplet size is critical. Spray droplet size is impacted by nozzle type, orifice size, spray angle, operating pressure, application speed, the pesticide formulation being applied, nozzle deflection angle, spray adjuvants, and sprayer electronics. In order to help applicators select the proper equipment and use it correctly, research is needed to determine what droplet size is best suited for different types of applications, how the various factors impact droplet size, and how to best mitigate drift under these application scenarios. Applicators need guidance on how to properly set up sprayers for lower volume applications in order to maintain the correct balance between efficacy and drift. There has been some recent work focusing on efficacy instead of drift reduction. Several projects have examined making effective applications to control Asian soybean rust. All of this work, however, focused on ground applications, which will be less effective than aerial applications in covering many acres of soybeans in a short time period, as will be required should a large outbreak of Asian soybean rust occur. While there has been research conducted involving improving the efficacy of aerial applications, much of it has focused on crops other than corn and soybeans, which are the two most important crops in Illinois. <P> Approach: Note: These methods match up with the individual projects described above. - Adjuvant performance will be evaluated through the use of tracer dyes deposited on mylar plates and spray coverage on water sensitive paper. Applications will be made in corn, and yield will also be used to evaluate effectiveness. Environmental factors, including wind speed, wind direction, temperature, and humidity, and crop characteristics, including canopy height and density, will be measured to determine their impact on spray deposition and coverage. - Fluorometric analysis of string, coverage analysis of water sensitive cards, and a high speed wind tunnel will be used to determine how the various adjuvants impact spray droplet size and pattern uniformity. - The spray patterns will be measured using a monofilament line strung through a corn field at ear height. A fluorometric analysis will determine the amount of dye deposited on the line. Crop characteristics, including canopy height and density, will also be measured as covariables. - Nozzle types will be evaluated for efficacy in field studies measuring spray deposition, coverage, disease or insect ratings, and yield. Drift potential will be evaluated by comparing setups in a high speed wind tunnel and a drift measurement tower. - An application of a contact herbicide to a cover crop will be used to determine which application method and volume provides the highest efficacy. - A portable droplet imaging system and specially developed software will be used to measure droplet size, and a pattern table will be used to measure spray pattern width. - Spray droplet size will be measured with a portable droplet imaging system and specially developed software. Droplet size for each nozzle will first be measured spraying water only. The different pesticides and adjuvants will then be sprayed at the same pressure setting to determine how they alter the droplet size.