Effects of Some Bacillus sp. Isolates on Fusarium spp. in vitro and Potato Tuber Dry Rot Development in vivo

摘要

Four Bacillus sp. isolates were individually essayed against Fusarium solani, F. oxysporum f.sp. tuberosi , F. graminearum and F. sambucinum following an in vitro dual culture plate technique and in vivo pre-inoculation tuber treatment. All tested bacterial isolates significantly reduced radial mycelial growth of Fusarium spp., on PDA after 3 days of incubation at 25°C, comparatively to the untreated controls. Light microscopic studies of antagonist x Fusarium spp. in vitro interaction showed several hyphal abnomalies traduced particularly by lesser mycelium density, severe hyphal lysis, lesser sporulation, mycelial cords formation and early chlamydospores induction observed only at the confrontation zone. Potato tubers, cv. Spunta, treated by Bacillus sp. 24 h before individually inoculation by Fusarium species, showed reduced dry rot development after 21 days of incubation at 25-27°C comparatively to untreated controls.