As an important pest on winter wheat, Rhopalosiphum padi (L.) causes damage to the wheat yield by sucking plant nutrients, transmitting plant viruses and producing mildew. R. padi has been reported to develop resistance to pyrethroids and neonicotinoids. To explore potential alternative approaches for R. padi control, the activity of 10 botanical insecticides was evaluated. Results suggested that the toxicity of rotenone and pyrethrins to R. padi were the highest and near to the commonly used chemical insecticides. When exposed to the low-lethal concentrations (LC 10 , LC 30 ) of rotenone or pyrethrins for 24 h, the lifespan and fecundity of adults in F0 generation decreased significantly compared to control. The negative effect could also be observed in the F1 generation, including the decreased average offspring, longevity of adult, and prolonged nymph period. The population parameters in F1 generation of R. padi were also inhibited by exposing to the low-lethal concentrations of rotenone or pyrethrins, including the decreased net reproductive rate, intrinsic rate of natural increase, finite rate of population increase, and gross reproduction rate. Co-toxocity factor results showed that mixtures of rotenone and thiamethoxam, pyrethrins and thiamethoxam showed synergistic effect. Our work suggested that rotenone and pyrethrins showed negative effect on the population growth under low-lethal concentrations. They are suitable for R. padi control as foliar spraying without causing population resurgence.
Jiangtao Dong,Hexin Li,Guoquan Wang,Haoming Li,Yanli Zhao,Xinan Li,Li Xu,Feng Zhou,Runqiang Liu
Pesticides play an important role in controlling plant diseases and insect pests to increase food production. Pyrethrin (Py), as a plant-derived insecticide, can effectively control wheat aphids owing to its fast knockdown, low concentration, and broad-spectrum insecticidal activity. However, Py is sensitive to UV irradiation and decomposes easily under sunlight, which leads to the loss of insecticidal activity. In this paper, we prepared one kind of metal organic framework nanopesticides based on zeolite imidazole-8 framework (ZIF-8) loaded with Py (Py@ZIF-8) via one-pot method for wheat aphid control. The prepared Py@ZIF-8 nanopesticides appeared acidic/basic pH and PO 4 3- stimuli-responsive properties for the controlled release of packaged Py by the disassembly of MOF skeleton and enhanced leaf wettability. The control efficacies of Py@ZIF-8 nanopesticides against wheat aphids reached ca. 86.67 ± 4.56 % under normal conditions, ca. 82.56 ± 3.88 % after water washing, and ca. 78.92 ± 4.34 % under exposure to UV irradiation, which appeared remarkably improvement compared with technical Py under UV irradiation and rain erosion condition, respectively. Even through the nanopesticides inevitably enter into soil or water, they appear good biosafety on wheat and cucumber seedlings by seed dressing, as well as zebrafish ( D. rerio ). Importantly, the eco-friendly nanocarriers will be ultimately degraded against bioaccumulation in crops based on the stimuli-responsive mechanisms. These results indicated that the prepared nanopesticides have an efficient wheat aphid control owing to the intelligent control release performance, as well as good UV and washing resistance, and good biosafety on non-target species, which have potential applications in agriculture against wheat aphids.
危险品化学品经营许可证（带存储）