Submitted to: Pest Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/16/2010
Publication Date: 9/3/2011
Publication URL: http://handle.nal.usda.gov/10113/60814
Citation: Hoagland, R.E., Boyette, C.D., Vaughn, K.C. 2011. Interactions of Quinclorac with a bioherbicidal strain of Myrothecium verrucaria. Pest Technology. 5(1):88-96. Interpretive Summary: The fungus Myrothecium verrucaria (MV), originally isolated from sicklepod, infects kudzu and several other weeds (bioherbicide). We have reported that the herbicide glyphosate can act additively with this fungus in infecting weeds. Another herbicide, quinclorac is not registered for kudzu control, but several other herbicides in its class are. In bioassays of hemp sesbania and sicklepod seedlings and in greenhouse tests using kudzu plants, sub-lethal concentrations of both MV and quinclorac caused additive effects on growth reduction and chlorophyll accumulation, and mortality. These findings under controlled conditions provide the basis for exploiting MV and quinclorac interactions to control invasive weeds.
Technical Abstract: In our laboratory, the fungus, Myrothecium verrucaria (Alb. & Schwein.) (IMI Accession No. 3601690) (MV), is being developed as a bioherbicide for kudzu [Pueraria lobata (Willd.) Ohwi] and other invasive weeds. We have found that spore and mycelial formulations of MV exhibit relatively rapid bioherbicidal activity when applied to the foliage of these weeds, and that application of MV with the herbicide glyphosate [N-(phosphonomethyl)glycine] can exhibit synergistic herbicidal interactions in certain instances. Several synthetic auxin-type herbicides are labeled for use to control kudzu. The auxin-type herbicide quinclorac (3,7-dichloro-8-quinolinecarboxylic acid) is not labeled for kudzu control, but is effective on hemp sesbania [Sesbania exaltata (Raf.) Rybd. Ex. Hill]. In bioassays of hemp sesbania and sicklepod (Senna obtusifolia L.) seedlings and in greenhouse tests using kudzu plants, sub-lethal concentrations of both MV and quinclorac (high purity, technical grade) applied to plant tissues caused additive and/or synergistic effects on growth, chlorophyll accumulation, and mortality. These important findings under controlled conditions provide the basis for further characterization of MV and quinclorac interactions on weeds under field conditions.