Robert Richardson

A need exists for assistance on several mesocosm and field projects in the area of assessing herbicide treatments to control invasive vegetation in a variety of aquatic sites in the US. This work also involves characterization of environmental fate and dissipation of aquatic pesticides. To facilitate execution of these projects, Dr. Howell has developed a specialized set of field skills that includes aquatic plant identification, quantitative vegetation assessment protocols, water quality and aqueous pesticide monitoring, and quantitative determination of off-target pesticide movement. The expertise provided through the IPA will enable execution of numerous ERDC field demonstration trials in FL, GA, AL, CT, NC, NY, WA, and ID. He will coordinate and direct sampling during field-scale aquatic herbicide treatments. He will assist in data collection, data analysis, proposal writing, and preparation of articles and reports describing the work. Dr. Howell will also make technical presentations on the work at professional conferences and meetings. Experience gained from these projects will allow Dr. Howell to further develop his skills while adding to his credentials at the University. The University will also benefit through broadening its research capabilities and relationship between CE-sponsored work and other University projects.

Hydrilla (Hydrilla verticillata) is a nonindigenous aquatic nuisance submersed plant with two biotypes that have historically spread across the United States. Recently, a third biotype of hydrilla has been characterized in the Connecticut River. There is very little published information available about this biotype. Research will be conducted to document important biological and phenological characteristics of the CR biotype. Results from these studies will document important factors in the growth and reproduction of the CR biotype that may be used to determine potential invasiveness of this biotype in comparison to the two biotypes commonly found in the US.

USACE has need for assistance with multiple field and mesocosm projects during 2020-22 exists per herbicide applications to evaluate treatment efficacy on invasive plants, impacts on non-target vegetation, and fate/dissipation of aqueous herbicide residues under a variety of conditions. This agreement will fund 50% of a NCSU employee to assist USACE with research needs.

Like other areas of weed management, herbicide applications for aquatic weed control are exclusively conducted via manned application systems. Whether by boat, land-based vehicle, or aircraft, aquatic herbicide operations are time and labor-intensive. Interest in utilization of unmanned aerial vehicles (UAS) for pesticide applications has increased significantly in the last decade due to advances in UAS technology. The UAS systems offer potential for increased precision and reduced time and labor requirements for pesticide application. However, there is very little known of the comparative efficacy between UAS and standard pesticide application systems, especially in aquatic weed management. This research will evaluate UAS application parameters for weed control efficacy and system efficiency.

Aquatic invasive plants (nonindigenous aquatic nuisance species) may have significant negative consequences upon the water systems that they invade. Hydrilla verticillata, in particular, has invaded a significant portion of the U.S. from Florida to California and as far north as Maine and Idaho. In order to properly assess and manage invasive aquatic plants, managers must determine both the scope of infestation as well as the specific species that present. In recent years, managers have been increasingly using hydroacoustic sensors to quantify submersed plant distributions and densities. This has provided increased efficiency over traditional techniques like point intercept surveys and aerial imagery. However, hydroacoustic sensors and current data processing only provide a representation of “biovolume” and do not provide speciation. Therefore, managers must still conduct some level of point intercept or diver effort in order to determine the specific species that are present. These activities are labor intensive and represent large efficiency gains if these activities can be replaced by advanced data processing. Automated plant identification methods, using high resolution true-color and multispectral imagery, have proven effective for land-based plants but have limited application to submersed aquatic vegetation. Despite the shortcomings of traditional techniques, our recent studies have shown that hydroacoustic imagery can be implemented for submersed aquatic species classification, with the use of deep learning, an advanced machine learning technique. Hydroacoustic data was collected via a small fleet of fully autonomous boats with both subsurface hydroacoustic imaging and herbicide deployment (for vegetation control) capabilities. The proposed research will integrate deep neural networks (DNNs) to develop advanced data processing techniques that classify submersed plant species from hydroacoustic data. While research to date has focused on a limited number of plant varieties (Hydrilla, Cabomba, Coontail, or “other”) and geographic locations, DNN training will be expanded to a much wider range of invasive species and locations. To minimize misclassification related to plant maturity, hydroacoustic imagery will also be collected throughout the growing season. True-color (RGB) images both above and below the water surface will be included (sensor fusion) to validate DNN classification.

Invasive plant management is key to ensuring proper ecosystem function and maintaining use of Florida’s water bodies. Aquatic invasive macrophytes, such as hydrilla (Hydrilla verticillata [L.f. Royle]) can have significant negative ecosystem and economic impacts on invaded areas (Pimentel et al. 2005). The objective for this research is to investigate hydrilla control from split applications of florpyrauxifen-benzyl and impact to major non-target species.

This is an Extension Implementation Project (EIP). Our Program Priority Areas are IPM Implementation in: Agronomic Crops (28%), Communities (40%), Specialty Crops (24%), and Pollinator Health (8%). The person who will be responsible for grant coordination and budget management, and participation in the SERA3 meetings is Dr. Danesha Seth Carley, Director for the NSF Center for IPM and the Administrative contact is Dr. Rich Bonanno, Director of NC State Extension, and Associate Dean College of Agriculture and Life Sciences. Through NC Cooperative Extension programs and diverse transdisciplinary team collaboration, we work to sustain and enhance environmental stewardship, reduce economic risks for growers and consumers, and protect human health by applying integrated pest management (IPM) in all suitable situations. Our goal is to increase coordination and improve efficiency of translating IPM research to the scientific community and stakeholders; as well as the residents of NC through extension and outreach programs. By working to synergize efforts and leverage resources, we are better able to promote development and adoption of IPM through collaborative programs and broad-based stakeholder participation. With a strong team of experts and close association with our Evaluation Specialist, we are able to document the value of IPM strategies and programs, and provide comprehensive success stories of IPM integration across NC. Through the outputs and outcomes from this program, NC Extension agents and stakeholders will become more knowledgeable about IPM and develop the skills necessary to implement IPM strategies in Agronomic Crops, Specialty Crops, Pollinator Health, and IPM in the Communities.

The goal of the Wilmington District Aquatic Vegetation Management Program is to maintain a healthy and sustainable ecosystem dominated by native aquatic vegetation at the District's dam and lake projects. Long term monitoring of aquatic vegetation will provide information necessary to identify trends and evaluate the effectiveness of management actions in public waters. Failure to identify effective and efficient methods to promote native aquatic vegetation and control invasive aquatic vegetation will result the degradation the environment and public resources. Knowledge gained will benefit public land managers addressing aquatic vegetation challenges in the region.

Hydrilla (Hydrilla verticillata) is a non-native invasive submersed aquatic plant. In North Carolina, this plant was first documented in Wake County in 1980. Initial infestations were confined to small ponds and lakes; however, by 1988 it had spread into Lake Gaston. The plant continued to spread to numerous Piedmont reservoirs across North Carolina and reached the large lakes on the Catawba River system in the early 2000's. Hydrilla has since spread to most Piedmont Reservoirs within the state.

Flopyrauxifen-benzyl (ProcellacorTM) is the newest chemical control option available to aquatic plant management. It can be used to selectively treat many of the troublesome aquatic weeds that are listed on North Carolina’s Noxious Weed List including Hydrilla verticillata (hydrilla), Ludwigia hexapetala (creeping water primrose), Myriophyllum spicatum (Eurasian watermilfoil), and Alternanthera philoxeroides (alligatorweed). The primary goal of this project is to develop appropriate recommendations for noxious aquatic weed control in North Carolina utilizing new herbicide technology.