Evaluación de la actividad antifúngica del quitosano en Alternaria alternata y en la calidad del mango 'tommy atkins' durante el almacenamiento

The objectives of this investigation were a) to determine the best concentration of chitosan to reduce Alternaria alternata development in relation to mycelial growth, germination and sporulation, b) to observe through scanning and electron microscopy the effect of chitosan level at the morphological and cellular level and c) to evaluate the efficiency of this compound to control A. alternata in mango cv. 'Tommy Atkins' fruits and its effect on fruit ripening during storage. Results demonstrated that the most effective concentration of chitosan was 1.0 %, because it reduced mycelial growth and sporulation by as much as 70 % and completely inhibited the germination of its conidia. In the scan and transmission micrographs an intense and ample vacuolization is observed along the mycelia and conidia, leakage of cytoplasmic material and presence of fibrilar material. There was no fungicidal effect of the chitosan when it was applied directly to mango fruits, although it reduced the extension of the disease by more than 50 %. Ripening of treated fruit was very similar to that of the control treatment.