Bt Research 2024, Vol.15, No.1, 10-19 http://microbescipublisher.com/index.php/bt 11 2 Overview of Bt Biopesticides 2.1 Mechanism of action Bacillus thuringiensis (Bt) is a soil bacterium that produces insecticidal toxins, which are highly specific to certain insect pests. The primary mode of action involves the ingestion of Bt spores and crystalline toxins by the target insect larvae. Once ingested, the alkaline environment of the insect gut activates the toxins, which then bind to specific receptors in the gut lining, causing cell lysis and ultimately leading to the death of the insect (Kumar et al., 2019). This specificity makes Bt a favorable alternative to broad-spectrum chemical pesticides, as it targets only the pest species without harming non-target organisms. 2.2 Types and applications Bt biopesticides are available in various formulations, including spores and crystals, which are used in agriculture, forestry, and mosquito control. There are different subspecies of Bt, each targeting specific pests. For instance, Bt subsp. kurstaki is effective against lepidopteran pests such as bollworms and loopers, while Bt subsp. israelensis and Bt subsp. sphaericus are used for mosquito control (Kumar et al., 2019). Recent advancements have also explored the combination of Bt with nanotechnology to enhance its efficacy, reduce dosage rates, and improve field persistence (Devi et al., 2019). Additionally, Bt-based biopesticides are being developed to address challenges posed by climate change, such as higher temperatures and extended shelf-life during storage. 2.3 Benefits and limitations Bt biopesticides offer several benefits over conventional chemical pesticides. They are less toxic to humans and non-target organisms, decompose faster, and are effective in smaller quantities (Ndolo et al., 2019). These attributes make Bt an integral component of Integrated Pest Management (IPM) programs, which aim to reduce the reliance on synthetic chemical pesticides. However, the adoption of Bt biopesticides faces certain limitations. Production and formulation costs can be high, and there are challenges related to the efficacy of downstream processing and formulation development (Rad et al., 2016). Additionally, despite the environmental and health benefits, the market growth of Bt biopesticides has been slower than expected, partly due to regulatory hurdles and farmers' reluctance to switch from synthetic pesticides (Sansinenea, 2016; Zhang et al., 2017). Bt biopesticides represent a promising and eco-friendly alternative to chemical pesticides, with specific mechanisms of action, diverse applications, and significant benefits. However, addressing the limitations related to production costs, regulatory challenges, and market acceptance is crucial for their broader adoption and success in sustainable pest management. 3 Regulatory Frameworks 3.1 International regulatory bodies The regulation of biopesticides is influenced by several international bodies that aim to harmonize and streamline the regulatory processes across different countries. Key organizations include the International Organization for Biological Control (IOBC), the European and Mediterranean Plant Protection Organization (EPPO), and the Organization for Economic Co-operation and Development (OECD). These bodies have made significant efforts to provide flexibility in biopesticide regulation, although challenges remain in achieving a uniform regulatory model that simplifies the registration process globally. The OECD, in particular, has been instrumental in developing guidelines and frameworks that member countries can adopt to ensure the safe and effective use of biopesticides (Arora et al., 2016; Desai et al., 2016). 3.2 National regulatory policies National regulatory policies for biopesticides vary significantly across countries, reflecting different levels of stringency and procedural complexity. For instance, the European Union (EU) has a more complex and lengthy registration process compared to the United States (US). The EU's regulatory framework, governed by Regulation (EC) No. 1107/2009, imposes stringent requirements that often result in longer approval times and higher costs for biopesticide developers (Frederiks and Wesseler, 2018). In contrast, the US regulatory system, managed by the
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