Practical Utilization of Botanical Extracts and Microbial in Controlling Dieback Disease of Tea [ Camellia sinensis (L) O. Kuntze] Caused by Fusarium solani (Mart.) Sacc.

In Northeast Indian tea plantations infection of Fusaruim solani , resulting dieback of tea plant is increasing which causes considerable crop loss during the recent times. In this investigation, native plant extracts, i.e. Acorus calamus L., Azadirachta indica A. Juss., Clerodendrum viscosum Vent., and Xanthium strumarium L. and microbials i.e. Bacillus subtilis and Trichoderma viride Pers. were utilized to evaluate the efficacy in controlling dieback disease of tea. These extracts inhibited the growth of Fusarium solani by 60-90%. In field application of C. viscosum and X. strumarium extracts reduced the disease up to 89.3% and 81% respectively. More than 70% disease reduction was observed when aqueous extracts of A. calamus and A. indica were used separately. Maximum disease reduction was achieved up to 86.9% due to application of T. viride . The results, thus, suggested the potential use of herbal extracts and microbial strains as an effective component of integrated disease management (IDM) schedule in the organic tea farming. The methods and rate of application are also discussed.