P-051 - Evaluating the capability of Fusarium oxysporum isolates to reduce Canada thistle stands under field and greenhouse conditions

Canada thistle (Cirsium arvense) is an Asteraceous weed that poses enormous challenges to organic crop growers in North America. Although management options are becoming increasingly limited for organic growers, members of Fusarium shine as bioherbicide alternatives. Fusarium oxysporum has been demonstrated to effectively control Canada thistle in controlled environments but results from field trials are still spotty for established thistle colonies. Environmental hues like soil moisture, pH, and temperature are suggested to impact F. oxysporum efficacy in the field. Our goal was to assess the value of F. oxysporum to suppress Canada thistle colonization of organic fields in large plot field trials and investigate the effect of soil moisture, pH, and temperature on F. oxysporum efficacy in the greenhouse. Canada thistle stock plants were propagated from cuttings of a single healthy plant, treated with fungicidal solution, and maintained in the greenhouse in pots filled with 50/50 Sunshine and MSU greenhouse soil mixes. Fungal inocula were prepared by mixing each isolate with autoclaved millet seeds. Field trials were established at three locations and treatments comprised of millet-based F. oxysporum isolates, uninoculated control, and a combination of the two fungal isolates.  Data will be collected on thistle incidence, weed biomass, weed health, Fusarium incidence, and crop biomass.  Followed across two years, field trials will examine the influence of inocula on rates of thistle colonization.