Antagonistic potential of medicinal mushrooms against pathogenic Ganoderma orbiforme in oil palm using a modified air-lift bioreactor (MALB).

Basal stem rot (BSR), a devastating disease caused by Ganoderma boninense (synonym G. orbiforme) significantly affects the oil palm industry, particularly in Indonesia and Malaysia. Current control measures for BSR are limited, prompting the need for environmentally sustainable biocontrol alternatives. In this study, the antagonistic potential of medicinal mushrooms against G. orbiforme to mitigate BSR in oil palm were evaluated. Among the tested species, G. lucidum exhibited the highest percentage inhibition of radial growth (PIRG) at 60.96%, followed by G. neojaponicum (50.37%) and Lignosus rhinoceros (13.50%). The biocontrol efficacy of G. lucidum was further assessed using a modified air-lift bioreactor (MALB) system, demonstrating that G. lucidum is non-pathogenic to oil palm and enhanced plant growth by 41.67% in terms of dry weight. In contrast, G. orbiforme inoculation resulted in typical symptoms such as leaf necrosis, yellowing and browning, Cercospora leaf spots and extensive hyphal mass growth, thereby confirming the pathogenicity of this species in oil palm. Infected plants experienced a significant reduction in dry weight by 115.31%. Furthermore, inoculating G. lucidum into plants either before or after inoculation with G. orbiforme positively impacted plant growth, with more pronounced effects when G. lucidum was introduced first, followed by the pathogenic G. orbiforme as tested in MALB system. These findings suggest that G. lucidum could be effectively utilized as a biocontrol agent to control BSR.