A bee-vectoring method has been recently developed against greenhouse insect pests. In this study, we conducted experiments to determine if bumble bees, bombus terrestris L. could vector Bacillus thuringiensis subsp. aizawai from hives equipped with a pathogen dispenser to leaf and flower of sweet pepper. First, in laboratory, insecticidal activity of B. t. subsp. aizawai NT0423 WP (Tobagi, Dongbu Hitek Co.) against 2nd instar larva of Spodoptera litura Fabricius was evaluated to determine if the amount of B. thuringiensis deposited on the leaf and flower would be sufficient to control the tobacco cutworm. The B. t concentration of the product in this experiment was estimated as 2.8-3.1 x 109 CFU/ml. The B. t. concentration on the body of bumble bees that was captured as they exited hives with filled pathogen dispensers was 4.6 x 109 cfu/ml. At the laboratory bioassay, the mortality of tobacco cutworm was serially measured depending on the pathogen concentrations. At the cage trials, the B. t. delivered by bumble bees was detected in bees, flowers and leaves. Through the several trials, the control effect on the tobacco cutworm has been investigating. The side effect on bumble bee from the first trial was not found in this experiment.