Bt Research 2025, Vol.16, No.6, 251-258 http://microbescipublisher.com/index.php/bt 255 cause any trouble. Bt toxins decompose very quickly in the environment. After being exposed to rain or light, their residues will soon disappear. This is undoubtedly good news for water sources and farmland soil. It is precisely for this reason that Bt is often regarded as a relatively "environmentally friendly" vector control method, which is less likely to cause long-term pollution and is suitable for repeated use (Ma, 2024). 5.3 Poor stability: effects of rain, UV exposure, and environmental conditions But then again, Bt is not without its drawbacks. Its biggest drawback might lie in the fact that it is "too prone to breakage". Once it encounters strong sunlight or rainy days, its insecticidal effect will be greatly reduced. Especially in some outdoor or damp environments, such as puddles and ditches where mosquitoes tend to breed, it is not easy for Bt to remain effective for a long time. Poor stability means that one either has to spray frequently or change the formula. Nowadays, some studies are also attempting to develop protective drug administration methods, such as encapsulation technology and sun protection coatings, etc. Whether these measures can solve the problem still depends on the subsequent experimental data. But at least for now, enhancing stability is indeed a crucial step in improving the practical application effect of Bt (Ma, 2024). 6 Case Study: Application of Bt in Dengue Fever Control 6.1 Review of Bt-based intervention programs in Malaysia, Brazil, and other regions In some countries with a high incidence of dengue fever, such as Malaysia and Brazil, relying solely on chemical agents is clearly no longer sufficient. So, the local media control project began to try to incorporate Bt preparations into mosquito prevention measures. Especially in these areas, the problem of mosquitoes' resistance to pesticides is becoming increasingly prominent. Bt, a relatively safe and low-resistance biological agent, seems more "reliable". In fact, many projects have long been using Bti (Bacillus thuringiensis Israel subspecies) to reduce the population of Aedes aegypti mosquitoes. In terms of actual effects, the density of mosquitoes and the survival rate of larvae in many areas have decreased significantly, which has indirectly played a role in reducing the risk of dengue fever transmission (Figure 2). Moreover, because Bt is harmless to humans and animals, its public acceptance is quite good, which is particularly crucial for promotion at the community level (Rusly, 2024; Miranda et al., 2024; Shafique et al., 2025). Figure 2 Bt-like colony morphology isolated from the soil samples (a); Light micrograph of Bt-Qo1-27, showing rod-shaped vegetative bacteria, stained with gram staining (b); Sporulation of the Bacillus thuringiensis showing parasporal crystals, vegetative cells and spores under Light microscope (100x100) (c); microphotograph taken from the phase-contrast microscope in late sporulation stage with 72hr incubation and >90% sporulation of the isolate Bt-Qol-84 (10x40) (d) (Adopted from Shafique et al., 2025)
RkJQdWJsaXNoZXIy MjQ4ODYzNA==