Bt Research 2025, Vol.16, No.6, 242-250 http://microbescipublisher.com/index.php/bt 243 This study reviews the application of remote sensing and geographic information System (GIS) technologies in monitoring the use of Bt biopesticides, with a focus on their potential to overcome the limitations of traditional methods. It explores how remote sensing can detect crop and pest conditions related to Bt application, and how GIS can integrate spatial data for monitoring and decision-making. And evaluate the benefits of these technologies for sustainable pest and disease management. This study aims to emphasize that remote sensing and GIS provide powerful tools for enhancing the accuracy, efficiency and environmental safety of Bt biopesticides in agriculture, thereby supporting sustainable crop protection and ecological conservation. 2 Mechanisms of Bt Bioinsecticides in Pest Control 2.1 Insecticidal mechanisms of Bt toxins and target pest species Not all insects will be "hit in the flesh" by Bt toxins, but for those pests with specific receptors in the midintestine, such as Lepidoptera, Coleoptera, diptera, etc., the effects of Cry toxins and Vip toxins are quite obvious. The principle behind them is actually not complicated: After the larvae eat them, the alkaline environment in the intestines activates the pretoxins, which then run to bind to the receptors on the intestinal cells. Eventually, the cells rupture and the worms die. Many Cry toxins have specific selectivity for particular insect species, which is also the basis for their "precise strikes". Interestingly, sometimes when several Bt toxins are used in combination, the effect is even stronger. They not only enhance the efficiency of pest control but also slow down the rate at which pests like the beet armyworm develop resistance (Baranek et al., 2021; Pinos et al., 2021). 2.2 Application methods of Bt formulations (sprays, granules, transgenic crops) How to use Bt? There is more than one way. The common spraying method used by farmers nowadays also requires advanced techniques. For instance, adding microcapsule coating can resist ultraviolet rays and extend the "service life" in the field. Granular agents are more suitable for being scattered into the soil to deal with pests that hide at the roots or underground. In contrast, genetically modified crops are like "armed with their own weapons", directly expressing Cry proteins within the plants. This way, even internal pests that cannot be reached by spraying can be prevented. However, no matter how good these genetically modified Bt crops are, one issue cannot be ignored - the risk of resistance. It is necessary to cooperate with management strategies, such as crop rotation or shelters, to avoid the situation where the disease is incurable after a few years (Duraisamy et al., 2023). 2.3 Environmental behavior and degradation characteristics after application Bt toxins are not always effective when they reach the fields. It is greatly influenced by the environment. For instance, it will decompose when exposed to too much sunlight, and soil microorganisms may also "eat" it. Although this makes it more environmentally friendly and reduces the impact on non-target insects, it also means that it needs to be resprayed or simply some protective agents should be selected to prolong the efficacy. Therefore, the application time must be calculated accurately. Studying the degradation patterns of Bt toxins is not only for safety but also helps farmers use fewer pesticides and take more pest control measures. After all, its characteristic of being both degradable and selective makes it a popular type of green pesticide in integrated pest management (Sanchis, 2011; Aswathi et al., 2024; Ragasruthi et al., 2024). 3 Fundamentals of Remote Sensing in Agricultural Monitoring 3.1 Principles and advantages of multispectral and hyperspectral remote sensing Remote sensing technology may sound rather sophisticated, but in fact, it has long permeated every corner of agricultural monitoring, especially in the two types of multispectral and hyperspectral monitoring. The crops in the farmland may look similar on the surface, but as long as these sensors are used to illuminate them, the trick can be seen. Multispectrum usually covers several wide bands, while hyperspectrum can obtain reflection data of hundreds of consecutive narrow bands. This also means that it can "see more precisely" and can capture some crop differences or early manifestations of diseases that are completely indistinguishable to the naked eye. It is worth mentioning that this technology does have advantages in monitoring the health and nutritional status of crops, especially in identifying physiological changes and biochemical reactions (Sishodia et al., 2020; Weiss et al., 2020). Of course, it is unrealistic to say that it can completely replace traditional methods, but it does have its place in assisting judgment and providing early warnings.
RkJQdWJsaXNoZXIy MjQ4ODYzNA==