Effect Of Sublethal Concentration Of Imidacloprid And Thiamethoxam On The Life-table Parameters And Feeding Behavior Of Sitobion Miscanthi

The Neonicotinoid insecticides is a new type of systemic insecticide, which have better control effect on aphids, and have become a research hotspot on new field of pesticides. This paper studied the biology and feeding behavior of Sitobion miscanthi feeding with two reagents including imidacloprid and thiamethoxam on dressing, determined the sublethal dose of two reagents and established the life-table on Sitobion miscanthi. This paper studied the effect of two reagents with the sublethal dose on Sitobion miscanthi with EPG, and did filed efficacy trials. All these results provide useful theoretical and emprirical foundation for later study. The main results of this study are as follows.1Control effect of seeds dressing with imidacloprid and thiamethoxam on wheat aphids and the residue dynamics in wheat leavesThe results showed that it was helpful for reducing population of wheat aphids and damages as well that wheat seeds were dressed with imidacloprid and thiamethoxam before sowing. Residues concentration of thiamethoxam in wheat leaves before early growth stage was significantly lower than imidacloprid, but there was no difference after late growth stage. The Neonicotinoid insecticides including imidacloprid and thiamethoxam significantly affect the1000-grain weight, and the treatments with thiamethoxam were higher than imidacloprid. In conclusions, imidacloprid and thiamethoxam has good control effect on wheat aphids, and thiamethoxam showed higher bioactivity and control efficiency to wheat aphids than imidacloprid.2Determination of sublethal dose and toxicity on Sitobion miscanthi with Neonicotinoid insecticidesThe experiment of toxicity test of two reagents on Sitobion miscanthi was conducted. The results showed that the LC50of two reagents including imidacloprid and thiamethoxam were:0.188g/kg、0.0484g/kg. There were significant differences between imidacloprid and thiamethoxam. The virulence of thiamethoxam was higher than imidacloprid, and the relative toxicity was3.88. 3The effect of life-table parameters of Sitobion miscanthi with Neonicotinoid insecticides in sublethal dosesThe experimental population life table of Sitobion miscanthi was setup. The life-table parameters of net reproduction rate(Ro), developmental duration(T), the intrinsic rate of natural increase(rm) and finite rate of increase(λ) were decreased except doubling time(DT), and the difference of CK was significant. This paper showed that the two reagents have negative effect and better control effect on Sitobion miscanthi.4The effect of feeding behavior of Sitobion miscanthi with Neonicotinoid insecticides in sublethal dosesThe feeding behavior of Sitobion miscanthi were investigated by EPG, the results showed that, the E1waveform, E2waveform and E1+E2waveform were shorter with the sublethal dose of two reagents on Sitobion miscanthi than CK, but non-feeding behavior (np waveform and C waveform) were longer than CK. The variance analysis showed the waveforms have significant differences between chemical treatment and CK. This paper showed that the sublethal dose of two reagents inhibited the feeding behavior on wheat aphids, showed negative effect. The result was consistent with the life table of Sitobion miscanthi. In conclusion, imidacloprid and thiamethoxam showed better control effect to Sitobion miscanthi, and are better reagents on control wheat aphids.