Project Number: 6402-22000-056-00
Project Type: Appropriated

Start Date: Feb 06, 2006
End Date: Aug 31, 2010

Objective:
Discover, develop, and improve augmentative bioherbicides, as viable weed biocontrol products through innovative field application, formulation, and mass-production strategies. Develop methodologies to eliminate, reduce or regulate undesirable secondary metabolites from biocontrol pathogens. Discover disease-promoting or weed defense-inhibiting chemicals that synergize bioherbicide. Identify or create biocontrol pathogens with novel traits. Develop molecular markers for bioherbicide strain identification, post-release monitoring, and environmental risk assessment. Discover novel information on genetic determinants and regulation mechanisms of pathogenicity, e.g., virulence, stability, host range and phytotoxin production.

Approach:
Assess biocontrol potential of several pathogens for control of various weeds: Myrothecium verrucaria for kudzu, redvine, and trumpetcreeper, Colletotrichum truncatum for hemp sesbania, and C. gloeosprioides cassiae for sicklepod. Assess formulations, interactions with agrochemicals, and application timing under field conditions. Assess combinations of host-specific bioherbicides to broaden the weed control spectrum. Develop methodologies for mass production and formulation to improve stability and virulence of bioherbicides. Reduce or eliminate undesirable secondary metabolites (e.g. trichothecenes) from M. verrucaria through mutagenesis, fermentation modifications, growth media alterations, strain selection, use of metabolic regulators, purification, and filtration of pathogen cultures. Inhibitors and other methods to metabolically inactivate trichothecene synthesis in M. verrucaria will be examined. Monitor toxin production via HPLC, ELISA, and HPLC-MS. Assay plant tissues from laboratory, greenhouse and field tests to determine enzyme and secondary plant constituent levels related to weed defense mechanisms against pathogens. Implement biochemical analyses of biomarker defense enzymes and plant constituents to ascertain mechanism of action of the pathogen and the synergistic action of combination of herbicides and other compounds with pathogens. Develop molecular methods for strain identification and post-release monitoring during field testing. Assess the ecological competence of biocontrol agents and the influence of environmental and weed host factors in field and controlled model systems.