Determinación de los agentes causantes de la flor dura en los frutos de banano

Abstract

Bananas, with an annual global production of 119.8 million tons, originate from Southeast Asia and are cultivated in 130 countries across tropical and subtropical regions, including Ecuador. Despite its economic importance, this crop is susceptible to diseases caused by bacteria and fungi that affect fruit quality. Specifically, in El Oro province, there are productivity challenges primarily attributable to phytosanitary problems of unidentified etiology, which hinders the development of effective control measures. Therefore, the objective of this study was to evaluate the microbiological load in banana fruits showing symptoms of "hard flower" or rot. The aim was to identify the causal pathogens and establish the foundation for developing specific management strategies that help mitigate the impact of this disease on banana production. Thirty isolates were obtained, including 20 bacteria and 10 fungi, on PDA medium. Morphological characterization of bacteria through Gram staining revealed that all were Gram-positive. Among the isolated fungi, the genera Fusarium spp. and Lasiodiplodia spp. were identified, with the specific species being: F. oxysporum, F. equiseti, F. circinatum, F. proliferatum, and Lasiodiplodia theobromae. Pathogenicity tests conducted with F. oxysporum, the most frequent isolate (5%), successfully reproduced the characteristic disease symptoms, including persistence and lignification of floral structures, fruit deformation, and progressive necrosis. The identification of F. oxysporum as the main causal agent provides a solid starting point for designing innovative and customized phytosanitary interventions that optimize the control and prevention of this important disease in the banana-growing areas of El Oro, Ecuador.