<p>Emamectin benzoate (EMB) is a biological pesticide with high insecticidal activity and a broad spectrum of impact, highly effective against many worms, insects, larvae and even fungi. However, the activity of EMB is often rapidly reduced due to easy decomposition under UV radiations, sunlight, natural light, pH and high temperature. Therefore, encapsulating EMB with polymers is extremely necessary, both to protect it from environmental degradation agents and to control the release process, thereby prolonging its activity and improving its effectiveness. In this study, EMB was encapsulated with a mixture of microparticles from two biodegradable polymers, polylactic acid (PLA) and polybutylene succinate (PBS). The effect of the PLA/PBS ratios on the encapsulation and release performance of EMB was elucidated. Besides, the morphological structure, thermal properties, UV and thermal stabilities of EMB-encapsulated microparticles were also investigated. Especially, the toxicity of these pesticide microparticles was also evaluated through contacting test with superworm. The experimental results showed that the pesticide microparticles fabricated from the predominant PLA or PBS components had small diameter sizes, 4.96 and 3.73&#xa0;μm, with EMB loading content above 29% and encapsulation efficiency higher than 87%. The microparticles still maintained their insecticidal efficacy up to 21&#xa0;days of toxicity test showing the potential applications of these microparticles as smart pesticides against pests and storehouse weevils, to contribute to the sustainable development of agriculture.</p> Graphical abstract <p>Structural morphology, release performance and toxic exposure test are the most important characteristics of slow-release pesticide formulations. For PLA/PBS microparticles loaded with EMB, the structural morphology of these microparticles depends on the variation of PLA/PBS ratio and strongly affects their other performances. LB20E corresponding to microparticles containing 20 wt% PBS exhibits a more perfect and finer particle structure, hence, they encapsulate EMB better and show more controlled EMB release with longer-lasting activity, as demonstrated by their ability to kill super worms for a longer period of time</p>