Actividad antifúngica in vitro de la quitosana Sigma frente a hongos fitopatógenos causantes del manchado del grano en el cultivo de arroz (Oryza sativa L.)

the antifungal activity of commercial chitosan sigma at concentrations of 300, 500, 700 and 1000 mg/l on mycelial growth and sporulation of the rice spotted grain pathogen fungi alternaria padwickii (ganguly) ellis, bipolaris oryzae (breda de haan) shoemaker, curvularia lunata (wakker) boedijn, fusarium verticillioides (saccardo) nirenberg, phoma sp. saccardo and sarocladium oryzae (sawada) gams & hawksworth was determined in vitro through the poisoning potato-dextrose-agar media. chitosan showed specificity in its inhibitory activity on fungi mycelial growth, and it was highest at concentration of 1000 mg/l, except for phoma sp. fungicidal action of the polymer on a. padwickii and b. oryzae was observed also and fungistatic action on the rest of fungi, with delayed growth on f. verticillioides. fungal sporulation reduction while the concentration product increased was obtained. that is why chitosan sigma is considered a promising alternative for the disease management