Development of a new broad-spectrum microencapsulation-based spray drying formulation of Bacillus thuringiensis subsp. kurstaki IMBL-B9 for the control of moths

Kalaiselvi Duraisamy; Nan Hee Yu; Seon Hwa Kim; Jong Hwi Baek; Ji Yeon Son; Euna Choi; Min Gu Park; Jiwon Kim; Jae Young Choi; Mee Kyung Sang; Yeon Ho Je; Jin-Cheol Kim

doi:10.3389/fmicb.2023.1273725

Development of a new broad-spectrum microencapsulation-based spray drying formulation of Bacillus thuringiensis subsp. kurstaki IMBL-B9 for the control of moths

Front Microbiol. 2023 Nov 22:14:1273725. doi: 10.3389/fmicb.2023.1273725. eCollection 2023.

Authors

Kalaiselvi Duraisamy¹, Nan Hee Yu¹, Seon Hwa Kim¹, Jong Hwi Baek¹, Ji Yeon Son¹, Euna Choi¹, Min Gu Park², Jiwon Kim³, Jae Young Choi², Mee Kyung Sang³, Yeon Ho Je^{2

4}, Jin-Cheol Kim^{1

5}

Affiliations

¹ Plant Healthcare Research Institute, JAN153 Biotech Incorporated, Gwangju, Republic of Korea.
² Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea.
³ Division of Agricultural Microbiology, National Institute of Agricultural Sciences, Rural Development Administration, Wanju, Republic of Korea.
⁴ Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea.
⁵ Department of Agricultural Chemistry and Institute of Environmentally Friendly Agriculture, College of Agriculture and Life Sciences, Chonnam National University, Gwangju, Republic of Korea.

Abstract

Certain Bacillus thuringiensis (Bt) strains such as Bt subsp. kurstaki and Bt subsp. aizawai have been widely used for pest management in agricultural practices. However, each strain only shows high specificity for pest control against a narrow range of lepidopteran species, and numerous lepidopteran pests have developed resistance to commercialized Bt strains. Therefore, there is a need for the development of novel Bt bioinsecticides which allow for potent and broad-spectrum insecticidal activity against lepidopteran species, including Spodoptera spp. (Noctuidae) and Plutella xylostealla (Plutellidae). In order to develop a novel bioinsecticide using Bt subsp. kurstaki IMBL-B9 (Btk IMBL-B9) that exhibits excellent insecticidal activity against three different lepidopteran species, we have developed a viable microencapsulation-based spray drying Btk IMBL-B9 formulation. The spore-crystal complex of Btk IMBL-B9 was microencapsulated using coating materials such as gum arabic, maltodextrin, and corn starch via spray drying. The encapsulated formulation of Btk IMBL-B9 presented an increased survival rate and storage stability at 54 ± 2°C for up to 6 weeks. The formulation showed similar insecticidal activity as the commercial bioinsecticide XenTari^® against P. xylostella. Under controlled greenhouse conditions, the Btk IMBL-B9 formulation was more effective against Lepidoptera spp. S. frugiperda and P. xylostella, than XenTari^®. These results suggest that the microencapsulation-based spray drying formulation of Btk IMBL-B9 can be used effectively for the control of a wide range of moths.

Keywords: Bacillus thuringiensis; Btk IMBL-B9; biological control; insecticidal activity; microencapsulation; spray drying.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by the Core Agricultural Material Localization Technology Development (project no.321054-05) and funded by the Institute of Planning and Evaluation for Technology in Food, Agriculture and Forestry, Republic of Korea.