Preparation of cyflumetofen nanocapsules and study on the controlled release performance and its field efficacy

Rotenone nanoparticles based on mesoporous silica to improve the stability, translocation and insecticidal activity of rotenone

Nanotechnology has been widely applied for pesticide carriers, which is an important way to improve the utilization, stability, and sustained release of pesticides. Mesoporous silica nanoparticles (MSNs) are a nanomaterial with adjustable particle and pore sizes, with a high specific surface area and good biocompatibility. Rotenone is a non-systemic botanical insecticide that is easily degraded in the environment. We used a modified soft-template method to prepare MSNs, in which rotenone was loaded using the solvent evaporation method. The prepared rotenone nanopesticide based on mesoporous silica showed considerable drug loading rates of 33.2%. Moreover, the prepared rotenone nanoparticles showed improved photostability and sustained release behavior, which improved the translocation of rotenone in tomato plants. Finally, the rotenone nanoparticles displayed superior insecticidal activity compared to traditional preparations. In summary, the rotenone nanopesticide improved the persistence and utilization rates of rotenone. These findings are of significance in reducing pesticide usage, mitigating environmental pollution, and ensuring food safety.

Surface modification of nucleopolyhedrovirus with polydopamine to improve its properties

BACKGROUND

Baculoviruses have been developed as promising biopesticides to control pests due to their high host specificity and virulence, and nontoxicity to humans and nontarget animals. However, their sensitivity to ultraviolet (UV) radiation and instability in the natural environment are major constraints to its large-scale application. In this study, polydopamine-nucleopolyhedrovirus microcapsules were established to improve the instability of baculoviruses in sunlight.

RESULTS

The optimal conditions for the preparation of polydopamine-nucleopolyhedrovirus microcapsules were as follows:  Spodoptera exigua nucleopolyhedrovirus (SeMNPV)concentration of 2 × 10⁸  polyhedral inclusion body（PIB） mL^-1 , reaction time of 6 h, and pH of 9.0. The particle size of the obtained microcapsules was about 1 μm. The microencapsulated baculovirus improved its thermal stability and wettability, and enhanced its insecticidal activity against Spodoptera exigua. Moreover, under the same UV treatment, the insecticidal effect against S. exigua larvae of microencapsulated baculovirus was only reduced by 8.89%, whereas that of the nonmicroencapsulated baculovirus was reduced by 27.27%.

CONCLUSION

Polydopamine-nucleopolyhedrovirus microcapsules provided better UV resistance and preparation stability compared with unmodified SeMNPV, and demonstrate an idea for the development of a baculovirus-based stabilized product. © 2021 Society of Chemical Industry.

Sodium selenite-carbon dots nanocomposites enhance acaricidal activity of fenpropathrin: Mechanism and application

As an essential trace element, selenium can be used to protect crops from pests, while, in nature, most crops cannot accumulate enough selenium from the soil to reach the effective dose for pest control. In this study, carbon dots modified with arginine in nano-scale was prepared and characterized, then, it was combined with sodium selenite to form selenium-carbon dots (Se-CDs). Function evaluation of Se-CDs showed that it could increase the absorption of selenium in plant leaves, promote the control efficiency of fenpropathrin, and protect plant from damage caused by Tetranychus cinnabarinus. In addition, we found that expressions of P450 genes and activity of P450 enzyme both decreased in selenium treated mites. In vivo, the acaricidal activity of fenpropathrin increased significantly when one of the P450 genes, CYP389B1, was silenced, and the recombinant protein of CYP389B1 could metabolize fenpropathrin in vitro. The results suggested that inhibiting the expression of P450 gene and repressing the detoxification of T. cinnabarinus was the molecular mechanism that how selenium promoted the acaricidal activity of fenpropathrin. The application of Se-CDs in the field will decrease the use of chemicals acaricides, reduce chemical residues, and ensure the safety of agricultural products.

The Enhancement of Antiviral Activity of Chloroinconazide by Aglinate-based Nanogel and Its Plant Growth Promotion Effect

Improving the efficiency and prolonging the duration of pesticides are of great significance in agricultural production. In this work, based on the antiviral compound chloroinconazide (CHI) synthesized previously, the improvement of the fabricated CHI-loaded alginate-based nanogel (CHI@ALGNP) was studied. It was found that CHI@ALGNP showed higher foliar adhesion than CHI and exhibited a sustained release for up to 7 days. CHI@ALGNP could also continuously activate the reactive oxygen species and antioxidant levels and induce the increase of salicylic acid content and the expression of its responsive gene PR2 for a long time, thus achieving sustained resistance to tobacco mosaic virus infection in Nicotiana benthamiana. Strikingly, CHI@ALGNP could release Ca2+ and Mg2+ to promote the growth of N. benthamiana. Taken together, for the first time, we have shown the improvement of a nanogel carrier to the antiviral activity and growth promotion of small molecular pesticides. As the alginate-based nanogel can be easily applied to the spray-based pesticide delivery technology, our study provides a new strategy for the development of new pesticide preparations and the application of multifunctional pesticides.