Bacillus thuringiensis (Bt) is widely used as an environmentally friendly insecticide compared to chemical insecticides. However, challenges such as difficulty in direct practical application, limited efficacy duration, and stability have been identified. To solve these issues, formulation-based research is being extensively conducted. In this study, the high insecticidal activity strain Bt IMBL-B9, identified in previous research, was subjected to large-scale cultivation using a fermentor. Subsequently, various formulations were developed through formulation processes. and characteristics such as their wettability, suspensibility and particle size were assessed to select the optimized formulation.

Spodoptera exigua is one of the worldwide distributed agricultural pest insects and has been known to show high resistance to conventional chemical insecticides. Autographa california multiple nucleopolyhedrovirus (AcMNPV) has been used as eco-friendly biological control agent for S. exigua, as it exhibits high level of host specificity, stability and safety. In this study, for formulation of AcMNPV, the optimal conditions for mass-production of AcMNPV polyhedra was established using S. exigua larvae. Mass-produced AcMNPV polyhedra was formulated as wettable powder using microencapsulation method and its control efficacy against S. exigua was evaluated both in laboratory and semi-field experiment. Chinese cabbage treated with the AcMNPV formulation showed significantly reduced damage rates, suggesting that the AcMNPV formulation in this study could be useful for control of S. exigua

Bacillus thuringiensis (Bt) is currently the most commonly used microbial pesticide. In the previous study, Bt IMBL-B9 known for its high toxicity against Spodoptera exigua, S. frugiperda and Plutella xylostella was characterized. To develop novel biopesticide, optimization of culture medium is required for the cost-effective mass production for toxin production of IMBL-B9. Through experimental design by Plackett-Burman design, ingredients that significantly influenced the production of IMBL-B9's toxin were selected. Using these results, the novel culture medium for IMBL-B9 was developed and the toxin yield of IMBL-B9 was significantly increased than conventional media by using this medium. These results could be useful for the development of biopesticides.

The beet armyworm, Spodoptera exigua, is one of the worldwide distributed agricultural pest insects and has been known to show high resistance to conventional chemical insecticides. Since it has been reported that secondary metabolites from actinomycetes show insecticidal activities against various insect pests, actinomycetes could be a potential source of insecticidal compounds. In this study, culture extracts of Streptomyces strains were tested for their insecticidal activity against Spodoptera exigua. Among them, culture extracts of IMBL-0003 strain which was identified as Streptomyces celluloflavus showed a high insecticidal activity (more than 90% mortality). These results suggested that secondary metabolites of this isolate could have potentials to be a efficient eco-friendly pesticide for controling Spodoptera exigua.

곤충생장조절제(IGR)은 대상 해충에 대한 특이성이 높고 환경에 대한 독성이 상대적으로 낮다는 장점으로 유기합성 살충제를 효과적으로 대체할 수 있는 유망한 수단으로 여겨진다. 현재 시판되는 곤충생장조절제는 작용 기작에 따라 유충호르몬 작용제(JHA), 탈피호르몬 작용제 (EA) 및 키틴 합성 저해제(CSI)의 세 가지로 구분된다. 최근 들어, 이집트숲모기의 Met과 FISC/CYC 유전자를 yeast two-hybrid system에 도 입하여 유충호르몬에 의해 매개되는 Met과 FISC/CYC의 결합을 in vitro에서 구현하였으며, yeast two-hybrid β-galactosidase assay를 통하 여 식물과 미생물 및 화합물 library로부터 다양한 유충호르몬 길항제(JHAN)가 분리되고 있다. 유충호르몬은 곤충의 발달, 생식, 휴면 등을 포함 한 다양한 생리 작용을 조절하기 때문에, 유충호르몬 길항제는 대상 해충의 내분비 신호 전달을 방해하여 비정상적인 발달 및 유충 단계에서의 치 사를 초래하며, 이는 유충호르몬 길항제가 넓은 기주 범위를 가진 살충제 개발에 효과적으로 이용될 수 있다는 것을 시사하였다. 따라서 본 논문 에서는 유충호르몬 길항제의 작용점인 Met에 의해 매개되는 유충호르몬의 신호 전달 체계와 친환경 살충제로서의 유충호르몬 길항제의 전망에 대해 알아보고자 하였다.