New York horseweed populations following an application of paraquat at a rate of 0.73 kg a.i./ha at 1 d after treatment. (Top left) Paraquat-resistant population collected from a New York vineyard (NY-Gr); (top right) paraquat-susceptible population collected from a New York roadside site (NY-Ro); (bottom left) paraquat-resistant population collected from a New York apple orchard (NY-Ap); and (bottom right) paraquat-susceptible population collected from a New York soybean field (NY-So).
Geneva, NY- A recent study released by Cornell University examines the response of horseweed (Erigeron canadensis), a troublesome weed in New York vineyards and orchards,paraquat, a burndown herbicide that some growers have used as a substitute for glyphosate.The findings provide essential insights for growers seeking effective weed management strategies in perennial crop systems.
Horseweed is a highly adaptable and competitive annual weed that can significantly reduce productivity in vineyards and orchards. This study evaluated the response of multiple horseweed populations to paraquat and diquat, a chemically related herbicide. Results confirmed herbicide resistance in some populations where paraquat had been substituted for glyphosate. Results also suggest emerging resistance to diquat. Herbicide resistance is a significant problem at local, regional, and national levels. These findings raise concerns about the continued effectiveness of paraquat and diquat for horseweed management in NY perennial cropping systems.
The research highlights the importance of integrated weed management approaches, including alternative herbicides, mechanical control, and cultural practices to mitigate resistance risks and maintain sustainable weed control. By understanding horseweed's response to these herbicides, growers can make informed decisions to optimize their vineyard and orchard management strategies.
Dr. Sosnoskie is an Assistant Professor of Weed Management in Specialty Crops at Cornell University. Her research program centers on weed ecology and management in fresh and processing vegetables, as well as tree fruit, vine, and berry crops. Her work includes evaluating new herbicides for specialty crops, addressing herbicide-resistant weed populations, and assessing the effectiveness of emerging weed control technologies.
The full story can be found on the ASHS HortScience electronic journal website at: https://doi.org/10.21273/HORTSCI18399-24
Established in 1903, the American Society for Horticultural Science is recognized around the world as one of the most respected and influential professional societies for horticultural scientists. ASHS is committed to promoting and encouraging national and international interest in scientific research and education in all branches of horticulture.
Comprised of thousands of members worldwide, ASHS represents a broad cross-section of the horticultural community - scientists, educators, students, landscape and turf managers, government, extension agents and industry professionals. ASHS members focus on practices and problems in horticulture: breeding, propagation, production and management, harvesting, handling and storage, processing, marketing and use of horticultural plants and products. To learn more, visit ashs.org.
