In vitro study on the biocontrol activity of Trichoderma against Phomopsis theae petch, infecting collar rot of tea in Bangladesh

Abstract

An attempt was made to study the biocontrol activity of Trichoderma against Phomopsis theae Petch, a causing
agent of Collar Rot of tea plant during 2006-2010 under in vitro condition. The pathogen was isolated from collar rot infected
tea plants collected from main farm and its experimental farm of Bangladesh Tea Research Institute (BTRJ), Srimangal,
Bangladesh. In order to isolate Trichoderma, soil samples were collected from 15 different marks of tea plantation of BTRI at
a depth of 0-9 inches. Trichoderma was isolated by serial dilution technique. The pathogen, P. theae was isolated from collar
canker affected tea plants by tissue plating technique. Interaction of the antagonists with the pathogen was studied by dual
culture method. Phomopsis theae and Trichoderma showed separately an increasing and significant radial growth of mycelium
at different intervals. The pathogen and antagonist grew until they came in contact with each other in dual culture. Growth of
the pathogen was inhibited, while the antagonist continued their grovrth and completely covered the pathogen. After 5 days of
plating, only 12.67% growth of P. theae and 87.33% oi Trichoderma were observed. It indicates that the percent inhibition on
the growth of the pathogen was 85.92%