Preparation of sustainable release mesoporous silica nano-pesticide for control of Monochamus alternatus

Monochamus alternatus is an important stem-borer that endangers economic and ecological forest, and also the main vector of pine wilt disease, a significant forest quarantine disease, which caused seriously losses for economic and ecological services. At present, M. alternatus mainly focuses on chemical control, among which Avermectin (AVM) is widely used as a high-performance spectrum insecticide. However, there are some problems, such as short duration, and environmental pressure caused by excessive use, which limit its application in pest control. In this paper, a drug delivery system based on dendritic mesoporous silica (DMSNs) was constructed to deliver biological pesticide AVM, so as to develop a new type of nano-pesticide, which could effectively control the stem borer M. alternatus and control Bursaphelenchus xylophilus. The AVM@DMSNs NPs composite was prepared by simple physical adsorption, and the loading rate was 85.73%, which significantly improved the utilization rate of AVM. The local application of AVM optimized by DMSNs showed that the contact toxicity (LC50 = 14.27 μg/mL) and stomach toxicity (LC50 = 10.90 μg/mL) of M. alternatus larvae were higher than those of AVM/EC and AVM treatment, which was based on the good permeability and adhesion of DMSNs. At the same time, DMSNs had better degradation ability in the natural environment: in PBS buffer solutions with different pH values, DMSNs completely degraded in 28 days. In addition, AVM@DMSNs NPs has a good absorption and transmission effect in trees, which indicates that nanoparticle-mediated pesticide delivery system will be a significant progress in the control of forest and fruit pests.