In vitro screening of rhizobacteria as biological control agents for controlling Thielaviopsis paradoxa a causal pathogen of black rot in MD2 pineapple

• Published in: IOP Conference Series: Earth and Environmental Science
• Main Author: Mohamad A.; Tahir N.; Wahab M.Z.A.; Othman N.M.I.; Sapak Z.
• Format: Conference paper
• Language: English
• Published: Institute of Physics 2024
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85206480330&doi=10.1088%2f1755-1315%2f1397%2f1%2f012010&partnerID=40&md5=289f6612e068b4edd8a126c870301695

Pathological disorder induced by pathogenic fungi is a major factor in pineapple fruit post-harvest losses. A fungal disease known as black rot caused by a facultative parasitic fungus, Thielaviopsis paradoxa (de Seynes) Hohn (Teleomorph: Ceratocystis paradoxa) is considered an economically important disease in pineapple as the disease can have a detrimental effect on fruit quality and quantity in the field and storage. The infected fruit displays disease symptoms of disintegrated fruit flesh, watery rot, and severe damage. This disease is hard to control as chemical fungicides are not applicable to mature pineapple fruits. Therefore, this study aims to screen rhizobacteria isolated from healthy MD2 pineapple plants as biological control agents against the black rot pathogen. A total of 25 culturalable rhizobacteria was obtained from soil samples through a multilevel dilution method of up to 108. These isolates were then in vitro screened for their potential to inhibit the growth of T. paradoxa using a dual culture test method and the percentage of inhibition radial growth (PIRG) of T. paradoxa was recorded. The results showed that two isolates coded as RB1 and RB2 gave the highest values of PIRG which were 85 and 80 % respectively. Based on morphological characteristics, RB1 was identified as Burkholderia sp. and RB2 as Bacillus sp. Their potential as biological agents, however, needs to be further evaluated in a real setting to confirm their capability to control the disease in pineapple. © 2024 Institute of Physics Publishing. All rights reserved.