Pesticides are the primary defending strategy against major biological invaders and important for ensuring national food security. Intelligent nanopesticides with precise controlled release modes are currently an emerging area of interest in the field of green, safe, and sustainable pesticide formulation. In this study, βcypermethrin (β-CYP) was loaded into ZIF-8 by the one-pot method, which successfully prepared a pH-responsive delivery nanoparticle (β-CYP/ZIF-8) to control termites. Results demonstrated that β-CYP/ZIF-8 had a mean diameter of 188 ± 2 nm and a loading capacity of approximately 21%. In vitro release experiments showed that β-CYP/ZIF-8 releases better in acidic than in neutral conditions due to the presence of intermediate acidunstable imidazole organic compounds. The acidic microenvironment in which termites thrive can promote β-CYP release due to ZIF-8 decomposition, thus improving pesticide targeting and reducing toxic side effects. The bioactivity survey confirmed that β-CYP/ZIF-8 could control termites (Coptotermes formosanus Shiraki) for a longer duration compared to commercial wettable powder (WP) and emulsifiable concentrate (EC). Moreover, an acute toxicity test showed an over 2-and 10-fold reduction in the acute toxicity of β-CYP/ZIF-8 to earthworms and zebrafish, respectively, compared to that of commercial WP and EC. Finally, the cytotoxicity assay of β-CYP/ZIF-8 showed higher safety to human hepatocyte LO2 cells. Overall, these β-CYP/ZIF-8 nanoparticles, prepared using the one-pot method, have great application potential in sustainable pest management and protection of the ecological environment.

Phenoxyalkanoic acid (PAA) herbicides are mainly metabolized by microorganisms in soils, but the degraders that perform well under alkaline environments are rarely considered. Herein, we report Cupriavidus oxalaticus strain X32, which showed encouraging PAA-degradation abilities, PAA tolerance, and alkali tolerance. In liquid media, without the addition of exogenous carbon sources, X32 could completely remove 500 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) or 4-chloro-2-methylphenoxyacetic acid within 3 days, faster than that with the model degrader Cupriavidus necator JMP134. Particularly, X32 still functioned at pH 10.5. Of note, with X32 inoculation, we observed 2,4-D degradation in soils and diminished phytotoxicity to maize (Zea mays). Furthermore, potential mechanisms underlying PAA biodegradation and alkali tolerance were then analyzed by whole-genome sequencing. Three modules of tfd gene clusters involved in 2,4-D catabolism and genes encoding monovalent cation/proton antiporters involved in alkali tolerance were putatively identified. Thus, X32 could be a promising candidate for the bioremediation of PAA-contaminated sites, especially in alkaline surroundings.

BACKGROUND Unmanned aerial vehicles (UAVs) are widely used to improve the efficiency of pesticide applications. Low‐volume spraying operations require more efficient deposition of droplets on the target surface. Therefore, pesticide deposition and retention on plant surfaces is a serious challenge for modern precision agriculture. Tank‐mix adjuvants have been used to improve spray dilutions performance; however, their effects on the physicochemical properties of spray dilutions, dosage delivery, and pesticide dosage are unclear. RESULTS Tank‐mix adjuvant 8860 significantly improved the physicochemical properties of spray dilutions, inhibited spray droplets rebound, improved the wetting and spreading performance of spray dilutions on wheat leaves, and increased the effective deposition of tebuconazole on wheat leaves. Even when its dosage was reduced by one‐third, the spray solution still showed excellent disease control and effective deposition of the active ingredient on wheat leaves. CONCLUSION The use of appropriate tank‐mix adjuvants in UAV‐based plant protection for wheat can significantly improve the performance of spray dilutions, increase the efficiency of pesticide dosage delivery, and improve disease control. These adjuvants can also help reduce the pesticide use while ensuring their effectiveness. © 2022 Society of Chemical Industry.

Silver is an important and efficient bactericide. Nanoscale silver has a large specific surface area, high target adhesion, strong permeability and high bactericidal activity. At present, the control of plant bacterial diseases is difficult, and the resistance of plant bacterial pathogens develops rapidly. Silver nanoparticles are expected to become a new generation of agrochemical to control plant bacterial diseases. In this study, a simple and green natural sunlight-induced method was used to prepare carboxymethylcellulose sodium-stabilized silver nanoparticles (CMC-SNs) with a particle size of around 13.53 ± 4.72 nm. CMC-SNs were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), energy-dispersive spectrometry (EDS), X-ray diffraction (XRD) and UV-vis spectroscopy and found to be spherical and evenly dispersed. The bacteriostatic activity of the CMC-SNs toward Xanthomonas oryzae pv. oryzae (Xoo) was tested. The minimum inhibitory concentration (MIC) of CMC-SNs to Xoo was 1 mg/L, and the minimum bactericidal concentration (MBC) was 2 mg/L. In addition, the antibacterial mechanism was studied by scanning electron microscope (SEM) and confocal laser scanning microscope (CLSM), which confirmed that the CMC-SNs had high antibacterial activity. In order to verify its impact on the environment, we conducted an acute toxicity test on zebrafish and found that Half lethal concentration (LC50) > 100 mg/L in zebrafish, or no acute toxicity. The ability of CMC-SNs to control rice bacterial blight was verified by a pot experiment.

BACKGROUND: Research on selenium nanoparticles (SeNPs) in chemical defense and chemotherapy of plants has developed rapidly owing to their high microbial toxicity, environmental safety, and degradability. Pine wilt disease (PWD) threatens pine forests worldwide; however, it is difficult to kill the nematodes (Bursaphelenchus xylophilus) inside the tree that cause PWD using traditional pesticide formulations. SeNPs could be the key to controlling PWD.RESULTS: In this study, approximately 50 nm SeNPs were prepared using a simple and green method, and chitosan was used to increase their biocompatibility and stability. The preparation and characterization results showed that the prepared SeNPs coated with chitosan (SeNPs@CS) were spherical and evenly dispersed. The bioassay results showed that SeNPs@CS had an LC 50 of 15.627 mg L −1 against B. xylophilus. In addition, the killing mechanism of SeNPs@CS against B. xylophilus was studied. Confocal microscopy and transmission electron microscopy demonstrated that B. xylophilus were killed by reactive oxygen species, and the penetration of nano-form materials to B. xylophilus was higher than that of non-nano-form materials. To verify the effective penetration of SeNPs in pine tissues, Cy5-labeled SeNPs@CS was observed inside pine needles and branches using frozen sections and confocal microscopy. In addition, the cytotoxicity of SeO 2 and SeNPs@CS was tested, and the results showed that the cytotoxicity of SeNPs@CS to MC3T3-E1 cells was reduced.CONCLUSION: These results show that SeNPs are expected to be used as a new strategy for the control of PWD with oxidative damage and high penetration to B. xylophilus and effective target penetration and biosafety.