Bt Research 2024, Vol.15, No.3, 131-140 http://microbescipublisher.com/index.php/bt 132 2 Overview of Bt-based Biopesticides 2.1 Development and mechanism of Bt biopesticides Bacillus thuringiensis (Bt) is a naturally occurring entomopathogenic soil bacterium that has been utilized as a biopesticide for over a century. The primary insecticidal components of Bt are crystal (Cry) proteins, which are produced during the sporulation phase of the bacterium. These proteins are highly specific to certain insect pests and are safe for non-target organisms, including humans (Devi et al., 2019; Kang et al., 2021). The mechanism of action involves the ingestion of Bt spores and Cry proteins by the target insect larvae, leading to the disruption of the gut cells, causing the insect to stop feeding and eventually die (Zhang et al., 2014; Kang et al., 2021; Li et al., 2022). Recent advancements have focused on enhancing the efficacy of Bt biopesticides through genetic engineering and the development of nanopesticides, which improve delivery and reduce the required dosage (Devi et al., 2019; Li et al., 2022). 2.2 Types and applications Bt-based biopesticides are available in various formulations, including liquid, powder, and granules, to cater to different agricultural needs. These formulations are used in a wide range of crops, including vegetables, fruits, and ornamental plants, as well as in forestry and mosquito control (Sansinenea, 2016; Devi et al., 2019). The versatility of Bt biopesticides is further enhanced by the development of transgenic crops that express Bt proteins, providing continuous protection against pests (Kang et al., 2021; Li et al., 2022). Additionally, innovative approaches such as the integration of Bt with RNA interference (RNAi) technology are being explored to manage resistance in pests and improve the sustainability of Bt products (Kang et al., 2021). 2.3 Benefits and limitations Bt-based biopesticides offer several benefits over chemical pesticides, including specificity to target pests, safety for non-target organisms, and minimal environmental impact (Gupta and Dikshit, 2010; Sansinenea, 2016; Devi et al., 2019). They are considered a key component of integrated pest management (IPM) strategies and are gaining acceptance worldwide due to their eco-friendly nature (Sansinenea, 2016). However, there are limitations to their widespread adoption. These include the development of resistance in target pests, the need for stable delivery systems, and the higher production and formulation costs compared to chemical pesticides (Brar et al., 2006; Devi et al., 2019; Kang et al., 2021). Additionally, regulatory challenges and the need for farmer education on the effective use of biopesticides are significant barriers to market adoption (Gupta and Dikshit, 2010; Sansinenea, 2016). In summary, Bt-based biopesticides represent a promising and environmentally sustainable alternative to chemical pesticides. Continued research and development, along with supportive regulatory frameworks, are essential to overcoming the current limitations and enhancing the adoption of these biopesticides in modern agriculture. 3 Regulatory Approval Process 3.1 International regulatory frameworks The regulatory approval process for Bt-based biopesticides varies significantly across different international frameworks. In the European Union, the regulation of biopesticides falls under the Pesticide Regulation (EC) No. 1107/2009, which encourages the use of less harmful active substances. Despite the potential benefits, manufacturers face challenges due to stringent approval and registration processes, which are similar to those for synthetic pesticides (Villaverde et al., 2014). In contrast, the global market for biopesticides is growing, but the regulatory landscape remains complex, with different countries having varying requirements for data on chemistry, bioefficacy, toxicity, and packaging (Gupta and Dikshit, 2010; Sansinenea, 2016). 3.2 National regulatory processes National regulatory processes for Bt-based biopesticides also exhibit considerable diversity. In India, for instance, the Central Insecticides Board and Registration Committee (CIBRC) oversees the registration of biopesticides. As of 2017, numerous microbial species and formulations have been registered, including various strains of Bacillus thuringiensis (Bt) (Kumar et al., 2019). However, the registration process is rigorous, requiring comprehensive
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