Fungos e fumonisinas no período pré-colheita do milho

Abstract

Fungal and mycotoxin contamination in maize can take place even before harvest time, with large economic losses in consequence. Fusarium spp. is a ubiquitous contaminant of corn in the field and several species of this genera are responsible for fumonisins production. Fumonisins are reported to be toxic to animals and humans, implicated in equine leukoencephalomacia disease and associated with pulmonary edema syndrome in swine and esophageal cancer in humans. The objective of this work was to identify critical points of fungal contamination and fumonisins production during pre-harvest growth stage. Results showed fungal growth since the dough stage, with no significant difference at both following stages: dent and physiological maturity. Non sporulated fungi were predominant at the silking stage (100%) and at the dough stage (95%). Saprophytes species were identified at the dent stage (23.25%). Fusarium spp. was evident since the dough stage (5%) increasing considerably through the dent stage (62.5%) to the physiological maturity (90%). All Fusarium spp. strains tested showed toxigenic potential. Fumonisins were evident at the latest development stages increasing considerably from the dent stage (0.2 ppm) to the physiological maturity (2.5 ppm). Authors suggest special attention and adopting preventive measures in relation to the dough stage, from which Fusarium spp. begin to be evident. © 2006 SBCTA.