The systemic fungicides belonging to the benzimidazoles group are widely used in agricultural practice and its indiscriminate use has been cause of environmental contamination. The dissipation and the loss of the pesticide biological activity depends, most of the time, on the microorganisms action. The present research was carried out with the objective to select fungi with potential to degrades benomyl and its hydrolysis product, carbendazim, and to quantify its degradation potential. The fungi were isolated from three different kinds of soils collected in the region of the irrigated agriculture of Guaíra, SP, Brazil, with intensive use of fungicides. Among the analyzed fungi, Alternaria alternata had the growth rate less affected by increasing the benomyl concentration. Under the maximum concentration, the inhibition for A. alternata was 22%; for the other ones it was superior to 45%. In a liquid culture medium, enriched with carbendazim, the biomass growth rate for A. alternata was 43% superior to growth rate observed in the culture media without carbendazim. A. alternata soon degraded the fungicide, reaching 66.21% of the disappearance of the product in two days. The half-life of carbendazim in this study was of 1.16 days.
degradation; Alternaria alternata; benzimidazoles; benomyl
