In Vitro Biological Control of Branch Canker (Macrophoma theiocola) Disease of Tea

Antagonist microorganisms, such as Trichoderma spp. have long been recognized as biological agents, for the control of plant disease and for their ability to increase root growth and development, crop productivity, resistance to abiotic stresses, and uptake and use of nutrients. An attempt was made to evaluate the in vitro biocontrol of branch canker (Macrophoma theicola) of tea plants by Trichoderma spp. Isolation of Trichoderma spp. and M. theiocola was done carefully. Pure culture of Trichoderma spp. and M. theiocola and their morphological characteristics were studied at different intervals. Five M. theiocola and five Trichoderma isolates were collected from mature tea plants and tea soils respectively of Bangladesh Tea Research Institute (BTRI) main farm area. The cultural morphology and antagonistic potentiality of Trichoderma spp. against branch canker pathogen (M. theiocola) were taken into consideration. Trichoderma spp. controls the growth of M. theiocola at different intervals. After 24 hour growth rate of Trichoderma was 9.3% and M. theiocola was 0.88%. The antagonistic potentialities of isolated Trichoderma against pathogens (M. theiocola) were observed at different intervals (24-120 hrs) and the percentage of inhibition was 82% which were observed after five days (120 hours) of inoculation. The Trichoderma spp. antagonizes the pathogens by several mechanisms such as antibiosis, competition, mycoparasitism or other form of direct exploitation. From this study it was revealed that, the Trichoderma spp. was highly effective to control the isolates of M. theiocola that is responsible for branch canker in tea cultivation.