Fusarium sp. Associated With Vanilla sp. Rot in Nayarit, Mexico
Vanilla production is threatened by fungi, which cause diseases such as Fusariumoxysporum. This research aimed to identify Fusarium associated with rot of wild Vanilla in Nayarit, México, by morphological, molecular and pathogenic characteristics. Morphological characterization was based on colony color, development of microconidia, macroconidia and chlamydospores on specific media, and growth rate. Molecular analysis was by sequencing the ITS1-5.8S-ITS2 region of rDNA gene. Pathogenicity test was conducted in healthy leaves and stems of wild Vanilla. The colonies were classified on four groups by pigmentation. Strains of fast, moderate and slow growth were observed. Of the 40 isolates, morphological analysis showed that 38 corresponded to Fusariumoxysporum and two to Fusariumsolani. The sequences of the ITS1-5.8S-ITS2 region of 38 strains had a similarity of 98% to 100% with Fusariumoxysporum, the remaining two strains with Fusarium sp. Nineteen strains originated lesions on leaves from the fourth day and up to 90 days in stems. It was found that F. oxysporum is mostly the causal agent of rot of wild Vanilla in Nayarit, Mexico.