A survey of Fusarium oxysporum in Georgia hemp farms and vegetable gardens

Recent changes in U.S. federal law have recognized the genetic and chemical differences between hemp and marijuana (Cannabis sativa L.), resulting in the legalization of hemp in the United States. The barriers to this plant’s growth in the state of Georgia are not well understood due to its prohibition for the past 80 years. Among the many possible obstacles is fungal disease. Fusarium oxysporum (Schlecht. emend. Snyder & Hansen) is a fungus that damages various crops and was previously researched as a biocontrol agent for C. sativa. Thus, this study surveyed hemp farms in Georgia to determine the prevalence of F. oxysporum in native soils via qPCR and correlate their abundance with the physicochemical properties of the soil (soil moisture, pH, ammonium, nitrate, and total inorganic nitrogen). Home vegetable gardens were also surveyed to be compared to the F. oxysporum abundance of hemp farms. We found that 5 out of 20 of the hemp soil samples and 1 out of 8 of the vegetable garden samples tested positive for F. oxysporum. Correlation analysis revealed a strong negative correlation between F. oxysporum abundance and soil moisture (r = -0.850, P=0.031). Although there were several plants reported to have symptoms matching that of fusarium wilt, no hemp farmer reported a substantial loss of crops from fungal disease. Overall, the findings of this study suggest that F. oxysporum may not pose a significant barrier to hemp farming in Georgia