Biological control of Thielaviopsis paradoxa on pineapple by an isolate of Trichoderma asperellum

An isolate of Trichoderma asperellum was tested for its antagonistic activity against Thielaviopsis paradoxa, the causal agent of black rot of pineapple, Anansas comosus. Results of our investigation clearly demonstrated antagonistic activity of T. asperellum against Th. paradoxa. The antagonistic activity was mainly due to coil formation around the pathogen hyphae by T. asperellum. The activity was found to be fungicidal. Pineapple fruits inoculated with 105 conidia/mL of Th. paradoxa, followed by an application of a formulation containing spores of T. asperellum within 10 and 30 min after inoculation, were free of disease when stored at 28 °C for 7 days. Fruits treated with the blank formulation (formulation without conidia) and the control fruits showed characteristic symptoms of black rot disease. Black rot symptoms also were observed on fruits that were inoculated with Th. paradoxa and held as inoculated controls under similar storage conditions. Chemical parameters namely; pH and titratable acidity among treated, untreated (controls) and fruits treated with a blank formulation showed no significant difference. The data suggest that a formulation of T. asperellum might be an alternate and ecofriendly method for the control of black rot disease of Pineapple.