Bt Research 2025, Vol.16, No.5, 204-213 http://microbescipublisher.com/index.php/bt 210 resistance to diseases, but may also have certain negative effects on feeding pests, hindering the growth and development of pests. The prevention and control concept of Bt and SAR mechanism has attracted attention in recent years, namely, by inducing plant SAR to reduce the fitness of pests, and then combined with Bt pesticides to remove pests (Frías et al., 2013). The increase in defense-related proteins and secondary biomass content in plant leaves under SAR state may weaken the digestive function of pests and increase the intensity of Bt toxin in the midgut. In addition, SAR can also improve the resistance of plants to pathogens. Therefore, in some complex environments where diseases and pests coexist, SAR-induced +Bt spraying achieves the effect of "killing two birds with one stone": it not only controls pests but also reduces the disease. 7 Ecology and Sustainability Analysis of Integrated Strategies 7.1 The effect of Bt integration with multiple biocontrol agents on biodiversity In farmland ecosystems, the introduction and conservation of biological control factors have positive implications for maintaining biodiversity. Compared with large-scale single use of chemical pesticides, Bt integrates multiple factors such as natural enemies and pathogens and other multiple factors to prevent and treat non-target organisms. Bt and most biological control agents have strong target specificity and will not kill large quantities of beneficial organisms such as pollinators and soil decomposers. For example, the large-area planting of Bt corn has reduced the spraying of broad-spectrum insecticides, which significantly increased the number of natural enemies such as spiders, parasitic wasps and ladybugs in the field, while secondary pests such as aphids are more inhibited, achieving natural control of pests at the landscape level (Figure 3) (Romeis et al., 2019). The combined action of multiple biocontrol agents can prevent excessive expansion of a certain group and buffer ecological balance. For example, in forest pest control, multiple parasitic wasps are released and Bt are administered simultaneously. Although there may be resource competition and interspecies interference between parasitic wasps or between parasitic wasps, research statistics show that the vast majority of combinations have positive effects on the overall control of target pests, and only about 12% of parasitic wasps-pathogen combinations show significant antagonism (Abbas, 2020). In rare cases, infection by a specific fungus (such as leukobassium) on another natural enemy (such as velvet erectile squash) will be avoided through reasonable time and space separation. Figure 3 Routes through which natural enemies could be exposed to plant-produced insecticidal compounds (Adopted from Romeis et al., 2019)
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