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ARS Home » Southeast Area » Stoneville, Mississippi » Biological Control of Pests Research » Research » Publications at this Location » Publication #341995
Research Project: Bioherbicidal Control of Invasive Weeds with Indigenous Plant Pathogens

Location: Biological Control of Pests Research

Title: Bioherbicidal enhancement and host range expansion of a mycoherbicidal fungus via formulation approaches

Author
item Boyette, Clyde
item Hoagland, Robert
item Stetina, Kenneth - Ken

Submitted to: Biocontrol Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/21/2018
Publication Date: 3/5/2018
Citation: Boyette, C.D., Hoagland, R.E., Stetina, K.C. 2018. Bioherbicidal enhancement and host range expansion of a mycoherbicidal fungus via formulation approaches. Biocontrol Science and Technology. 28(3):307-315. https://doi.org/10.1080/09583157.2018.1445199.

Interpretive Summary: Eastern black nightshade (Solanum ptycanthum; EBN) is a problematic weed found throughout the eastern U.S. Control of EBN is difficult due in part to its tolerance or resistance to many commonly used herbicides. Greenhouse and field experiments were conducted to compare the effects of an invert (water - in - oil) emulsion (IE) versus an surfactant - water (water + Tween 80) spore formulations of a bioherbicidal fungus (Colletotrichum coccodes) for controlling this weed. Greenhouse tests revealed that several other solanaceous weeds including the exotic invasive species sticky nightshade (S. sisymbriifolium), wetland nightshade (S. tampicense), and tropical soda apple (S. viarum) were infected and killed at significantly greater levels by the fungus/IE formulation as compared to the fungus/surfactant formulation. Field tests revealed that >90% EBN control and dry weight reductions occurred when plants were treated with the fungus/IE formulation, while the fungus/surfactant formulation failed to control weeds. These results further demonstrate the utility of this invert emulsion formulation in promoting the efficacy of this pathogen. Results also suggest its potential to improve bioherbicidal potential of other pathogens which may have been previously rejected for development due to infectivity and environmental and constraints.

Technical Abstract: Eastern black nightshade (Solanum ptycanthum; EBN), found throughout the eastern U.S., is difficult to control and a problematic weed, partly due to its tolerance or resistance to certain herbicides. Greenhouse and field experiments were conducted to determine the effects of an invert (water - in - oil) emulsion (IE) on the host range and weed control efficacy under field conditions of the fungus Colletotrichum coccodes (NRRL strain 15547) for biocontrol of EBN. Field tests revealed that >90% EBN control and dry weight reductions occurred when plants were treated with the fungus-IE formulation. Other solanaceous weeds [hairy nightshade (S. sarrachoides), American nightshade (S. americanum), black nightshade (S. nigrum), cutleaf nightshade (S. triflorum), sticky nightshade (S. sisymbriifolium), wetland nightshade (S. tampicense), tropical soda apple (S. viarum), and jimsonweed (Datura stramonium)] were infected and killed at a significantly greater level by the fungus in the IE as compared to a fungus-Tween-80 surfactant formulation. These results and previous research further demonstrate that this invert emulsion formulation can promote the efficacy of this pathogen. These results also suggest this invert emulsion may be useful to improve the efficacy of other bioherbicides, some of which may have been previously rejected for development due to environmental and infectivity constraints.