The foliar crop tea (Camellia sinensis O’Kuntz), that yields the cheapest beverage in India is largely produced in North-East India including the Darjeeling Himalayan slope and its Terai (foothills and plains). Naturally occurring entomopathogenic bacteria could be isolated from two species of loopers, Buzura suppressaria and Hyposidra talaca and also from a slow but steady leaf feeder, the red slug caterpilla (Eterusia magnifica) and a new invading hairy caterpillar (Arctornis submarginata) that strip tea bushes of their mature and maintenance leaves. Infected larvae of B. suppressaria and H. talaca yielded spore forming bacteria with crystal proteins and appeared to share many features in common with Bacillus thuringiensis kurstaki (Btk), but differed from Btk in shape of their crystal, biochemical tests, growth phase, molecular weight of crystal protein, and major whole body proteins. A lower LC50 and reduced LT50 value than Btk were also evident. All the Bacillus strains i.e. BS01 from B. suppressaria, HT01 and HT02 from H. talaca were found mutually cross infective to both the looper species but were not pathogenic to Bombyx mori (multi voltine strain of silkworm). Field application in RBD of most pathogenic strain of HT01 proved alone to be quite effective at the field dose of 5000 µg/ml concentration. Mean live larvae of H. talaca recovered in field after 7 days of spraying the bacterial formulation, was 3.93% . So, the present study revealed that naturally occurring highly pathogenic Bacillus strains could be made effective in looper control through a process of isolation, identification, testing, formulation and application especially in biorational or bioorganic tea plantations. Bacterial strain close to Btk but with a slightly higher LC50 value and a much reduced LT50 values could be isolated from red slug caterpillars of E. magnifica. Its laboratory based evaluation proved its killing efficacy in the early stage red slug caterpillars. So, this strain of Bacillus also hold a substantive promise of being used in biocontrol of the concerned pest. The bacterial strain isolated from hairy caterpillars of Arctornis submarginata was tested to be a Bacillus with typical spore. The strain showed a longer doubling time and difference in biochemical tests from Btk. Moreover, this strain (Arc 01), showed a lower LC50 value and a shorter LT50 values as compared to Btk when tested against early instars of A. submarginata. Thus proving that the strain had a definite killing efficacy against the concerned pest when tried in laboratory conditions. Importance of nucleopolyhedrovirus (NPV) extracted from cadavers of looper caterpillars (B. suppressaria and H. talaca) could be well realized due to their high infectivity and low LC50 values. Field application of NPV (1 x 107 OBs/ml) proved efficacious in bringing down the looper population in Terai tea estate. Besides the Bacillus strain of A. submarginata, a granulovirus was also isolated from naturally infected population. The GV was found to have an LC50 value, 4.46x104 OBs/ml and LT50 values, 3.87 days for 1x107 OBs/ml concentrate. This GV added an effective bioagent to the biopesticide arsenal for future control of this emerging pest, especially in the organic and biorational tea plantations of Himalayan Terai and