扇形雾喷头磨损对微生物农药施药性能的影响

Effects of flat-fan nozzle wear on application of microbial pesticides

农林病虫害防治中,微生物农药因其具有不污染环境、防治作用持久、无残留、杀伤特异性强等优点,已逐渐成为研究热点和重要方向,但因利用率较低、施药技术落后、专业施药器械匮乏等原因限制了其在农林病虫害防治中的应用。笔者分析了扇形雾喷头球头结构与雾滴尺寸、雾滴沉积量和农药中的活体微生物存活率等微生物农药活性衡量指标的相关性。建立了喷头磨损测试系统,雾滴沉积量和微生物农药活性测试系统,利用三维测量仪和激光粒度仪等试验测试了扇形雾喷头球头结构尺寸与雾滴沉积量和农药中活体微生物的存活率的变化关系。采用SPSS软件通过线性回归分析方法量化分析微生物农药活性各性能指标与扇形雾喷头球头尺寸之间的相关性,建立了线性回归数学模型。分析认为:目前沿用的喷头失效评估方法不适用于微生物农药施药,为保持微生物农药活性,满足其使用要求,TP11002型扇形雾喷头磨损率应小于6.74%,球头短轴尺寸不能超过0.5 mm,TP8004扇形雾喷头磨损率应小于6.91%,球头短轴尺寸不能超过0.45 mm。结果表明,微生物农药活性不能仅以农药中的活体微生物存活率为衡量指标,应考虑到雾滴沉积量和活体微生物存活率的综合影响。扇形雾喷头球头结构尺寸与雾滴沉积量和活体微生物存活率存在线性关系,根据扇形雾喷头球头结构尺寸的变化判断微生物农药活性是可行的。本研究结果为微生物农药施药时对施药器械的失效评估和提高微生物农药防治效果提供了理论和技术支撑。

Microbial pesticides have become the hotspot in biological control of agriculture and forestry diseases and insect pests because they have the advantages of no pollutant emission,no chemical residue,sustainable control,etc.However,the application of microbial pesticides is still limited because of the lowavailability,backward spraying technology and the lack of appropriate sprayer. In this paper,the correlation between the pesticide evaluation indexes（ droplet size and deposition,and viability of microbial pesticides） of the biological activity and the orifice structure was analyzed; and the mutual relationship between these evaluation indexes was experimentally studied by using nozzle wear experiment system,droplet deposition and viability of microbial pesticides measurement system,3 D-admeasuring apparatus and laser diffraction particle analyzer. The mathematical models of the relationship between the size of spherical-top of flat-fan orifice and microbial pesticides activity were established. The results showed that the current assessment method for nozzle failure was not suitable for microbial pesticides application. In addition,the evaluation of microbial pesticides activity should take into account the influence of droplet deposition and viability of microbial pesticides. There exists a linear relationship between the spherical-top of flat-fan orifice and the droplet deposition and the viability of microbial pesticides. Accordingly,the microbial pesticides activity can be evaluated by the size of the spherical-top of flat-fan orifice. The results provide the foundation on howto assess nozzle failure during the application of microbial pesticides and howto treat plant pests and diseases effectively.