In Vitro Evaluation of Bio-Control Agents and Fungicides against <I>Ganoderma lucidum</I> Causing Basal Stem Rot of Arecanut

Abstract

Basal stem rot or Ganoderma wilt caused by Ganoderma lucidum (Curtis Ex.Fr.) Karst is one of the major constraints in arecanut cultivation in Assam, India. Pure culture of Ganoderma was isolated from fruiting bodies of diseased arecanut palms. Twenty-two Trichoderma spp. and twelve Pseudomonas fluorescens isolates were prepared from rhizosphere of healthy arecanut palms from different locations. The study was carried out during 2012-13 and 2013-14. Dual culture study revealed that among the Trichoderma spp., T. viride Tv-16 isolate, produced maximum reduction in radial growth of G. lucidum (88.56%) followed by Ta-7 and Ta-10 with 88.26 and 84.07 per cent inhibition over control after 144 hrs of incubation respectively. Among the twelve isolates of P. fluorescens, Pf6 was most effective, followed by Pf10 with 77.55 and 77.33 per cent inhibition over control, respectively. Seven fungicides were assayed for their efficacy against the test pathogen at 0.1, 0.2 and 0.3 per cent concentration. Among the systemic fungicides, hexaconazole 5EC and tridemorph 80EC completely inhibited the growth of G. lucidum at all the concentrations. Among the contact fungicides, mancozeb 75%WP (86.11% inhibition over control) gave maximum control against the pathogen. Compatibility study of fungicides with T. viride Tv-16 revealed that the systemic fungicides, carbendazim 50%WP, hexaconazole 5%EC and tridemorph 80%EC were highly sensitive to T. viride with 100 per cent inhibition at all the tested concentration. Non-systemic fungicide mancozeb 75%WP was found to be compatible, whereas copper oxychloride 50%WP and captan 50%WP showed low to moderate degree of compatibility with T. viride Tv16.