Bt Research 2024, Vol.15, No.5, 232-239 http://microbescipublisher.com/index.php/bt 237 demonstrated approximately a 2-fold increase in toxicity against various lepidopteran pests compared to the individual toxins (Xue et al., 2023). Another study highlighted that the combination of Cry9Aa and Vip3Aa proteins exhibited synergistic activity against Chilo suppressalis, indicating that these combinations can achieve higher insecticidal toxicity and delay resistance development (Wang et al., 2020). In contrast, standalone proteins often show limited efficacy. For example, the standalone use of Cry1Ac or Cry1Fa resulted in significantly lower resistance levels in diamondback moths compared to the combined knockout of two ABC transporter genes, which caused over 10 320-fold resistance to Cry1Ac (Zhao et al., 2020). This underscores the enhanced effectiveness of synergistic combinations over single proteins. 7.2 Economic and environmental advantages of synergistic use The use of synergistic combinations of Bt toxins offers several economic and environmental advantages. Economically, the increased efficacy of synergistic combinations can lead to reduced application rates and frequencies, thereby lowering the overall cost of pest management. For instance, the combination of Cry1Ca and Vip3Aa not only showed high efficacy but also suggested potential for developing new bioinsecticides with high effectiveness against S. exigua, which could reduce the need for multiple applications (Baranek et al., 2021). Environmentally, synergistic combinations can contribute to more sustainable pest management practices. The use of multiple toxins can help in delaying the development of resistance in pest populations, as seen with the Cry9Aa and Vip3Aa combination, which helps in maintaining the long-term effectiveness of Bt toxins. The use of synergistic combinations can reduce the environmental load of insecticides, as lower quantities are needed to achieve the desired pest control, thereby minimizing the impact on non-target species and ecosystems. The development of databases like TOXiTAXi aids in the research and application of Bt toxins by providing comprehensive data on the biocidal activity of various toxin combinations, facilitating more informed and effective pest management strategies (Baranek et al., 2020). 8 Implications for Integrated Pest Management (IPM) 8.1 Combining biological, chemical, and cultural practices The integration of Bt toxins with other insecticidal proteins and practices offers a multifaceted approach to pest management. Bt crops, such as those producing Cry and Vip proteins, have been shown to effectively manage pest populations and reduce the reliance on chemical insecticides. By combining these biological controls with chemical and cultural practices, such as crop rotation and the use of refuges, the overall effectiveness of pest management strategies can be enhanced. This integrated approach not only helps in managing pest populations but also delays the evolution of resistance, thereby extending the efficacy of Bt crops (Gassmann, 2021). 8.2 Enhancing long-term pest control sustainability The sustainability of pest control strategies is a critical concern, particularly with the increasing instances of resistance to Bt crops. The use of synergistic combinations of Bt toxins, such as Cry and Vip proteins, has been shown to provide a broader spectrum of control and reduce the likelihood of resistance development. Incorporating RNA interference (RNAi) technologies with Bt toxins in transgenic crops has demonstrated potential in delaying resistance and enhancing long-term pest control sustainability (Ni et al., 2017). These strategies, when integrated into a comprehensive IPM plan, can help maintain the effectiveness of pest control measures over extended periods (Jurat-Fuentes et al., 2021). 8.3 Synergistic Bt in cotton and corn IPM systems In cotton and corn IPM systems, the use of Bt crops has been particularly impactful. For instance, Bt cotton and corn producing multiple Bt toxins have significantly reduced pest populations and minimized crop damage 156. The incorporation of Vip proteins alongside Cry proteins in these crops has further enhanced their effectiveness against resistant pest populations. Moreover, the adoption of IPM practices, such as the use of non-Bt refuges and crop rotation, has been crucial in managing resistance and ensuring the long-term success of Bt crops in these systems (Anderson et al., 2019). The synergistic use of Bt toxins in cotton and corn IPM systems exemplifies the potential for integrated approaches to achieve sustainable pest management.
RkJQdWJsaXNoZXIy MjQ4ODYzNA==