Screening of antagonistic bacteria from healthy pineapple variety MD2 and its potential against bacterial heart rot disease / Naimah Husin

Bacterial heart rot disease caused by pathogenic bacteria Erwinia chrysanthemi is one of the common diseases of pineapple. Current industry practices for controlling the disease through cultural practices and application of chemical synthetic of Benomyl which is not a long lasting control method. This study aims to evaluate the potential of beneficial bacteria isolated from healthy pineapple leaves against the disease pathogen. The disease pathogen was isolated from symptomatic pineapple leaves with the appearance of water soaked and heart rot disease symptoms such as rotten basal tissues. Pathogenicity test was conducted to fulfil the Koch's Postulates. The same procedure for isolation of beneficial bacteria from healthy pineapple plant variety MD2 was carried out. A total of 25 bacterial isolates were successfully isolated from the healthy pineapple leaves and tested against the bacterial pathogen via agar well diffusion method. In vitro assay was utilized to measure the ability of isolated beneficial bacteria in the form of inhibition zone and its growth on media. An isolate identified as Bacillus cereus (BC3) showed the potential of antagonistic activity towards the pathogen. The isolate was further assessed in vivo under rain shelter conditions. The result showed that the isolate was able to suppress the disease symptoms. This study suggested that B. cereus (BC3) could be further explored for its potential as biological control agent for controlling the disease under field condition.