Biological Characteristics of Pathogen Causing Maca Root Rot Disease and Its Fungicides Laboratory Screening

Purpose Our aim was to elucidate the biological characteristics and suitable fungicides for the pathogen of root rot on maca and to provide theoretical basis for high yield and high quality cultivation of maca.Method The mycelium growth of F. avenaceum ROT-2 were studied through single factor test method under different conditions including different culture medium, different carbon source, nitrogen source, temperature, pH, lighting and ventilation conditions. In addition, the fungicides against the pathogen were investigated in this study.Results The results indicated that the pathogen mycelium grew well on PDA and OA under 21℃, the colony diameter was larger and the mycelium was thicker. Starch and NaNO3 were the best carbon and nitrogen resource, respectively. The pathogen hyphe were grown well under pH 4-10, while the optimum pH for mycelial growth was 6, and the lethal temperature was 55℃. The dark and stuffy conditions were more conducive to the mycelium growth.Conclusion The most effective fungicide was 80% Mancozeb among the three tested reagents, and the relative inhibition rate was 88.8% under the mass concentration of 1.00 mg/mL, when the EC50 values was 0.140 9 mg/mL.