Out of 22 isolates of Fusarium subglutinans f. sp. ananas tested in preliminar trials, it was selected for the final experiment four isolates representing the resistant group (E272, E274, E279 e E283), and four representing the susceptible group (E285, E277, E278 e E290) of Fusarium subglutinans f. sp. ananas to benomyl. The isolates were collected on diseased pineapple plants from the southern area of the Espírito Santo State, and inoculated on three months old pineapple (Ananas comosus) seedlings, cv. Perola (susceptible) and Primavera (resistant), under greenhouse conditions, to study the virulence of the pathogen. The pineapple seedlings were inoculated by immersion of the seedlings in a conidial suspension (10(5) conidia/ml) scratched from PDA plates, after they had been injured on their crown area. The results showed that the cv. Primavera was resistant to all isolates tested. The cv. Perola showed symptoms of fusariosis 15 days after the inoculation with the isolates resistant to benomyl. The isolates susceptible to benomyl caused symptom of the disease 45 days after the inoculation. The isolate E272 (resistant to benomyl) was the most virulent isolate to cv. Perola, whereas the isolates E277 and E278 (susceptible) to benomyl were the least virulent. The susceptible isolates to benomyl caused symptoms of the disease on the cv. Perola 45 and 60 days after the inoculation. In conclusion this study showed that there are differences in virulence between the isolates of F. subglutinans f. sp. ananas resistant and susceptible to benomyl to pineapple.
