Interaction of a Myrothecium verrucaria Mycelial Preparation and a Glyphosate Product for Controlling Redvine ( Brunnichia ovata ) and Trumpet Creeper ( Campsis radicans )

A mycelial formulation of the bioherbicidal fungus Myrothecium verrucaria (Alb. & Schwein.) Ditmar: Fr. (MV) was tested alone and in combination with a commercially available glyphosate [N-(phosphonomethyl)glycine] (GLY) product for controlling the invasive vines, redvine [Brunnichia ovata (Walt.) Shinners], and trumpet creeper [Campsis radicans (L.) Seem. ex Bureau] in field experiments conducted near Stoneville, MS. Several application timing regimens were evaluated (Fall, Spring, Fall + Spring, and Spring + Fall). We found that a Fall + Spring application of MV + GLY controlled redvine and trumpet creeper by 95%, 12 days after the second treatment, through a synergistic interaction of the fungus and glyphosate. Disease symptomatology was characterized by rapid necrosis of leaf and stem tissues, with mortality occurring within 72 h. Neither glyphosate alone, nor MV alone, effectively controlled either weed species under any application timing regimen. No visual disease or herbicide damage occurred on glyphosate-resistant soybean plants in the treated test plots. These results suggest that some formulations of glyphosate, mixed with the bioherbicide MV, can effectively control redvine and trumpet creeper, two of the most troublesome weeds in the row crops of the Mississippi Delta region in the mid-southern U.S.