Bioherbicidal Activity of Albifimbria verrucaria (formerly Myrothecium verrucaria) on Glyphosate-Resistant Conyza canadensis

Authors: Hoagland, Robert; Boyette, Clyde; Stetina, Kenneth - Ken

Submitted to: The Journal of Fungi
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/19/2023
Publication Date: 7/22/2023
Citation: Hoagland, R.E., Boyette, C.D., Stetina, K.C. 2023. Bioherbicidal Activity of Albifimbria verrucaria (formerly Myrothecium verrucaria) on Glyphosate-Resistant Conyza canadensis. The Journal of Fungi. 9(7)773. https://doi.org/10.3390/jof9070773.
DOI: https://doi.org/10.3390/jof9070773

Interpretive Summary: Horseweed (Conyza canadensis), native to and widespread in North America, is problematic to many crops (cotton, grain sorghum, corn and soybean) and some horseweed biotypes have developed resistance to various herbicides, including glyphosate. The scientists at the USDA-ARS, Crop Production Systems Research Unit and Biological Control of Pests Research Unit, Stoneville, MS, conducted greenhouse and field studies to determine the bioherbicidal efficacy of a virulent isolate of the fungal plant pathogen, Albifimbria verrucaria (AV), formerly Myrothecium verrucaria, as a bioherbicide against glyphosate-resistant and –susceptible horseweed. Spray applications of mycelial formulations of AV infected both glyphosate-resistant and -susceptible horseweed plants at various growth stages. Young plants in the rosette leaf stage of growth were controlled more efficaciously than older plants that had bolted or that were in the inflorescence stage, nevertheless severe injury and mortality also occurred in mature plants. Results indicate that this bioherbicidal fungus can infect and control glyphosate-resistant horseweed, thus demonstrating its potential as a bioherbicidal agent against this troublesome weed that has become resistant to various herbicides.

Technical Abstract: The effects of bioherbicidal activity of the fungal phytopathogen, Albifimbria verrucaria (AV), formerly Myrothecium verrucaria, against glyphosate-resistant and –susceptible Conyza canadensis (horseweed) were studied under greenhouse and field conditions. Spray applications of mycelial formulations of AV infected both glyphosate-resistant and -susceptible C. canadensis plants at various growth stages. Young plants in the rosette leaf stage of growth were controlled more efficaciously than were older plants that had bolted or that were in the inflorescence stage, nevertheless severe injury and mortality also occurred in mature plants. Results indicate that this bioherbicidal fungus can infect and control C. canadensis, thus demonstrating the potential of this fungus as a bioherbicidal agent against this troublesome weed that has become resistant to various herbicides.