No abstract

Fruitlet core rot (FCR) is a worldwide fungal disease of pineapple, which occasionally occurs on susceptible cultivars in Taiwan. This study describes the fungal pathogens of FCR and their occurrence in Taiwan for the first time. A total of 51 fungal isolates were obtained from diseased fruitlets and blossom cups of ‘TN20’, a susceptible cultivar planted in Taiwan. These isolates were identified as the Talaromyces species T. amestolkiae, T. funiculosus, and T. stollii and Fusarium species F. ananatum, F. oxysporum, and F. annulatum based on phylogenetic analyses. All of them have been described as FCR pathogens in other countries, if considering that F. annulatum has often been misidentified as F. proliferatum. To facilitate identification, four pairs of species-specific primers were developed, which enabled rapid identification of T. amestolkiae, T. funiculosus, and T. stollii by multiplex polymerase chain reaction (PCR) and F. ananatum by PCR. Two types of diseased fruitlets, “wet” and “dry”, were observed on ‘TN20’, and T. amestolkiae, T. funiculosus, T. stollii, and F. ananatum could be isolated from both types. In addition, Talaromyces and Fusarium species were isolated from blossom cups at high frequencies, but few fungi were isolated from healthy tissues. The specific primers designed in this study could provide a useful tool to study FCR in the future, and the findings could provide a better understanding of the ecology and epidemiology of FCR.