Rapid Detection of Ganoderma Disease of Coconut by using ITS-PCR and Assessment of Inhibition Effect of Various Control Measures by Fungicides and Bioagents

Abstract

Two biochemical and molecular methods have been applied for detecting the Ganoderma, basidiomycete fungi causing basal stem rot disease (BSR) of coconut in the early stage itself. Leaf, stem/bark and root extracts recorded the highest optical density values than their corresponding healthy tissues. Increased transmittance values observed from the extracts of diseased leaf, stem, bark and root extracts compared healthy tissues. For polymerase chain reaction (PCR) test, the primer generated from the internal transcribed spacer region one (ITS 1) of ribosomal DNA gene of Ganoderma, which produced a PCR product of 160 bp in size is used for early detection. Different systemic, non-systemic and bioagents were screened against Ganoderma isolates for in vitro management of the disease. Among the non-systemic fungicides tried in vitro, captan, mancozeb, and thiram at 0.2 percent completely inhibited the growth of the fungus. In the case of systemic fungicides trideomarphm, hexaconzole and carbendazim at 0.1 percent recorded highest percent inhibition of mycelium growth. Dual culture study carried out with three different species of Trichoderma revealed that T. harzianum and T. koningii were found effective.