Submitted to: Biocontrol Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 10, 2006
Publication Date: October 10, 2006
Citation: Boyette, C.D., Reddy, K.N., Hoagland, R.E. 2006. Glyphosate and bioherbicide interaction for controlling kudzu (Pueraria lobata), redvine (Brunnichia ovata), and trumpetcreeper (Campsis radicans). Biocontrol Science and Technology. 16(10):1067-1077. DOI: 10.1080/09583150600828742. Interpretive Summary: Kudzu, redvine and trumpetcreeper are troublesome viney weeds throughout the southeastern U.S. Scientists at the Southern Weed Science Research Unit, Stoneville, MS tested a native fungal plant pathogen, Myrothecium verrucaria, alone, in combination with, prior to, and following treatment with the herbicide glyphosate at recommended usage rates for control of these weeds at temperature of 20, 30, and 40 degree C. Kudzu was most adversely affected by the fungus, followed by trumpetcreeper and redvine, as indicated by mortality rates and dry weight reductions at all temperature but disease severity increased as treatment temperatures increased. A synergistic disease interaction occurred when the fungus was applied 2 days after glyphosate treatment. Application of the fungus combined with or prior to glyphosate application can improve the bioherbicidal activity of M. verrucaria for controlling kudzu, redvine, and trumpetcreeper.
Technical Abstract: In controlled environment experiments, the bioherbicidal fungus Myrothecium verrucaria (Alb. & Schwein.) Ditmar:Fr was tested alone, in combination with, prior to, and following treatment with glyphosate for control of kudzu [Pueraria lobata (Willd.) Ohwi], redvine [Brunnichia ovata (Walt.) Shinners, and trumpetcreeper [Campsis radicans (L.) Seem. Ex Bureau] at temperatures of 20º, 30º, and 40º C. At all temperatures, kudzu was most adversely affected by the fungus, followed by trumpetcreeper and redvine, as indicated by greater mortality rates and reduced dry weights. Trumpetcreeper and redvine mortalities and dry weight reductions were synergized when the fungus was applied 2 days after the glyphosate treatment. Application of the fungus combined with or prior to glyphosate treatment resulted in reduced weed control. Disease development was favored by high temperatures (30 and 40º C) when compared to 20º C. Infected weeds of each species exhibited similar disease symptomatology within 12 h following treatment at incubation temperatures of 30 and 40º. Disease symptomatology was characterized by necrotic flecking on leaves that coalesced into large lesions. Symptoms progressed from infected cotyledons and leaves to produce stem lesions within 48 h. The fungus sporulated profusely on infected tissue was easily reisolated. These results suggest that timing of glyphosate application can improve the bioherbicidal activity of M. verrucaria for controlling kudzu, redvine, and trumpetcreeper.