Studies On Two High-efficiency Nano-pesticides Formulation For Environmental Protection

While the wide use of pesticide ensures the agricultural production, the immense negative effect it brings to the environment cannot be ignored. "High-efficiency, low-noxious, low-residue" has been a natural trend for the development of future pesticide. Therefore, it is an -important task for pesticide researchers to exploit a kind of pesticide which can both improve biological activities and reduce residue.Based on the study of the preparation method, characterization, photocatalysis, modifcation and adsorption of photocatalytic degradative nano-TiO2, this thesis confirmed the composite methods of the two different kinds of pesticide, nano-TiO2 and chlorfenapyr and pirimiphos-methyl. And it studied the photocatalytic degradation and biological activities of the two kinds of nano-pesticides. It also conducted an exploratory study on the residue of nano-chlorfenapyr in cabbage and soil.The results demonstrated that the adding of nano-TiO2 could obviously improve photocatalytic degradation. The photocatalytic degradation rate of 10% nano-chlorfenapyr which is irradiated in unltra-violet lamp for 1hr, 3hrs, 5hrs and 22.5hrs is 12.9%, 23.1%, 32.6% and 65.0% higher than 10% chlorfenapyr SC respectively. The photocatalytic degradation rate of 5% nano-pirimiphos-methyl irradiated in unltra-violet lamp for Ihr, 2hrs and 4hrs is 14.2%, 17.2% and 11.1% higher than 5% pirimiphos-methyl CK respectively.The nano-pesticides can obviously improve the biological activities of pesticide. The results of the indoor bioassay test showed that the virulence of 10%nano-chlorfenapyr is 1.68 times stronger than that of 95% chlorfenapyr TC and the virulence of 5% nano-pirimiphos-methyl is 1.32 times stronger than that of 90% pirimiphos-methyl TC. The results of the field test showed that the field effect of 10% nano- chlorfenapyr to spodoptera litura on cabbage is 20% superior to that of chlorfenapyr EC and the Id and 3d corrected controlling ratios are 4.89% and 3.05% higher respectively. The effect of field of 5% nano-pirimiphos-methyl to Chilo suppressallis Walker on rice is 16.4% higher than that of 20% pirimiphos-methyl EC and the protection effect upon seedlings is 18.4% better.In addition, the nano-pesticides can also efficiently reduce the residue of pesticide in crops and soil. The result of residue and dissipation of chlorfenapyr showed that the half-life of 10% nano-chlorfenapyr in soil is 4.38 days and that of 10% chlorfenapyr SC in soil is 10.71 days; the half-life of 10% nano-chlorfenapyr in cabbage is 1.50 days and that of 10% chlorfenapyr SC in cabbage is 3.86 days. The results of ultimate residue test of chlorfenapyr showed that the residue amount of 10% nano-chlorfenapyr in the soil which is treated with high and low rate 3 days and 7 days after 2 and 3 treatments has not been detected and is lower than 0.012mg/kg. The amount of residue which is detected in cabbage after 3 days is obviously higher than that after 7 days. The amount of residue after 3 days in the low-rate-treated cabbage is less than 0.02-0.033mg/kg and that in the high-rate-treated cabbage is less than 0.02-0.122mg/kg. But the amount of residue after 7days is less than 0.02-0.047mg/kg.The results of the research showed that the nano-pesticides formulation is a kind of promising pesticide formulation which conforms to the developing trend of future pesticide, will have a bright application prospect and bring obvious economic benefit, social benefit and environmental benefit.