【作者】 张萍；

【导师】 姜兴印；

【作者基本信息】 山东农业大学 ， 农药学， 2018， 硕士

【摘要】 减量施用是现代农药研究非常重要的方向,喷雾助剂的使用是实现农药减施增效的重要途径之一。农药喷施后,如果短时间内发生降雨,靶标表面的部分农药有效成分因雨水冲刷而流失,导致防治效果降低;在喷雾液中添加合适的喷雾助剂能够有效的降低雨水对施药效果的影响。我国夏玉米主要产区的病虫害多发于7、8月份,该时间段降雨频繁,对玉米田农药喷雾防效产生不利的影响。为了减轻降雨对病虫害防治的不利影响,有必要研究开发在玉米上应用的耐雨水冲刷喷雾助剂。本文探究了实验室研制的4种喷雾助剂AY904-1、AY904-2、AY904-3和AY904-4对嘧菌酯药液在玉米叶片上接触角、持留量、药液干燥时间和表面张力等性质的影响,并测定了喷雾助剂的溶胀度和溶解性、喷雾助剂与氯虫苯甲酰胺喷雾液桶混喷雾对玉米生长的安全性;然后主要采用荧光显微镜法评价了几种不同雨水冲刷条件下喷雾助剂对玉米叶片上嘧菌酯持留量的影响,筛选出了能显著提高嘧菌酯耐雨水冲刷性能的喷雾助剂及添加浓度。再通过高效液相色谱法定量测定了部分试验处理在雨水冲刷后玉米叶片上嘧菌酯的持留率,与相对应浓度处理的嘧菌酯荧光覆盖率数值进行相关性分析,证明了使用荧光显微镜法评估喷雾助剂耐雨水冲刷性能的可靠性。最后通过测定在模拟降雨冲刷条件下所筛选喷雾助剂AY904-1和AY904-2对嘧菌酯防治玉米大斑病[Exserohilum turcicum(Pass.)Lenoad&Suggs.]的室内防效,更准确的评价了两种喷雾助剂的性能,进而为喷雾助剂在农业上的应用推广提供参考。以下是主要的研究结果。1.4种喷雾助剂均能够降低嘧菌酯药液在玉米叶片表面的接触角,其中添加了质量分数为1%的AY904-1或AY904-2的处理结果较药剂对照差异显著;AY904-1、AY904-2和AY904-3均能够显著降低药液的表面张力;AY904-1和AY904-2能够显著提高嘧菌酯药液在玉米叶片表面的持留量。随着温度升高,喷雾助剂薄膜的稳定性降低,AY904-1和AY904-2在水中的性质比较稳定,薄膜在水中长时间浸泡也不易分解;而AY904-3和AY904-4的效果较差,在18℃的条件下,两种助剂膜分别在60 min和45 min时完全解离。2.玉米生长安全性试验结果表明,4种喷雾助剂对玉米的生长均不会产生不良的影响,表现出了很高的安全性。3.在不同的雨水冲刷条件下,探究了4种喷雾助剂对嘧菌酯药液在玉米叶片上持留量的影响。结果表明,玉米叶片上嘧菌酯的持留量随着模拟降雨强度的增加而减少;当降雨时间间隔大于2h时,能有效降低雨水冲刷对嘧菌酯持留量的影响;在嘧菌酯药液中添加质量分数为0.25%~0.50%的AY904-1或0.50%~0.75%的AY904-2,能够明显提高玉米叶片上嘧菌酯的耐雨水冲刷效果,而AY904-3和AY904-4的综合效果并不理想。4.添加质量分数为0.25%、0.50%的AY904-1或0.50%、0.75%的AY904-2能够有效降低雨水冲刷对180mg/L嘧菌酯药液防治大斑病的不利影响。在经过强度为20 mm/h、时间为5 min的模拟降雨冲刷后,对照处理对玉米大斑病的防效为28.26%;添加了质量分数为0.25%、0.5%AY904-1的嘧菌酯药液,对玉米大斑病的防效分别能达到67.93%和72.21%,添加了质量分数为0.5%、0.75%AY904-2的嘧菌酯药液,对玉米大斑病的防效分别为67.22%和70.31%。5.荧光显微镜法所测嘧菌酯的荧光覆盖率和高效液相色谱法所测嘧菌酯的持留量在数值之间具有良好的相关性。因此,选择荧光显微镜法评价嘧菌酯在玉米叶片上持留量的方法是可靠的。更多还原

【Abstract】 Nowadays,pesticide reduction is a very important direction for pesticide research,and the use of spray adjuvants is one of the important ways to reduce the use dose of pesticide and increase its efficiency.If it rains in a short time after spraying the pesticide,some of the pesticide active ingredients on the surface of the target will be washed away due to rain erosion,which ultimately leads to a reduction in control effectiveness.So we can effectively reduce the effect of rain on the application of pesticides by adding suitable spray adjuvants to the spray solution.In the main producing areas of summer maize in China,the diseases and pests often occur in July and August.Frequent rainfall during this period will have a significant adverse impact on the control of pesticide spray in maize fields.In order to reduce the adverse effects,it is necessary to research the spray adjuvants used on maize.In this paper,the influence of the spray adjuvants(AY904-1,AY904-2,AY904-3 and AY904-4)on the contact angle,retention amount,drying time and surface tension of the azoxystrobin solution on maize leaves were investigated.And the swelling degree and solubility of the spray adjuvants and the safety of chlorobenzamide tank-mixed with spray adjuvants spraying on the safety of maize growth were also determined.Then we mainly used fluorescence microscopy studied the effect of spray adjuvants on the retention of azoxystrobin on maize leaves under different rainwater washout conditions,and screened out spray adjuvants and their concentration that can significantly improve the rainfastness of pesticides.According to the test results,we have screened two spray adjuvants and their adding concentrations that can significantly improve the washout performance of pesticides.We selected a part of the test treatment,and quantitatively determined the retention of azoxystrobin on maize leaves after rain erosion by high performance liquid chromatography.And we also found fluorescence microscopy were in agreement with a quantitative HPLC method in which the exact quantity of active ingredient on a maize leaf was determined before and after a rain wash.Finally,by measuring the effects of AY904-1 and AY904-2spray adjuvants on the control efficacy of azoxystrobin against northern corn leaf blight under simulated rainfall scouring conditions,the performance of the two spray adjuvants were more accurately evaluated.The following are the main research results.The spray adjuvants all can reduce the contact angle of the azoxystrobin liquid on the surface of maize leaves,especially the treatment of AY904-1 and AY904-2 with a mass fraction of1%.AY904-1,AY904-2 and AY904-3 can significantly reduce the surface tension of azoxystrobin liquid.What’s more,AY904-1 and AY904-2 can significantly increase the retention of the liquid on the surface of maize leaves.As the temperature rise,the stability of the spray adjuvant films decrease,the properties of AY904-1 and AY904-2 in water are relatively stable,the films are not easily broken and decomposed after being soaked for a long time.But the firms of AY904-3 and AY904-4 are unstable in water.For example,under the conditions of 18°C,the AY904-3 and AY904-4 films completely dissociated at 60 min and 45 min respectively.The results of maize growth safety tests showed that the four spray adjuvants had no adverse effects on the growth of maize and they all showed high safety to the maize.Under different rainwater scouring conditions,the influence of four spray adjuvants on the retention of azoxystrobin liquid on maize leaves was investigated.The results showed that the retention of azoxystrobin on maize leaves decreased with the increase of simulated rainfall intensity.When the rainfall interval was greater than two hours,the effect of rain erosion on the retention of azoxystrobin could be effectively reduced.Adding mass fraction of 0.25%~0.50% AY904-1 or 0.50%~0.75% AY904-2 to the spray solution can improve the ability of azoxystrobin to resist rainwater erosion on maize leaves.The overall effect of AY904-3 and AY904-4 are not ideal.Under simulated rainfall conditions,the effectiveness of 180mg/L azoxystrobin tank-mixed with AY904-1(mass fractions of 0.25% and 0.50%)and AY904-2(mass fractions of 0.50%and 0.75%)was tested for northern corn leaf blight disease.The results showed that the selected adjuvants could reduce the adverse effect of rain erosion on the application effect.After a simulated rainfall duration of 5 min and a strength of 20 mm/h,the control treatment had a control effect of 28.26% on the disease.In comparison,the mass fraction addition of0.25% AY904-1 in the treatment could still achieve 69.76% of the control effect on the northern corn leaf blight,the mass fraction addition of 0.50% AY904-2 in the treatment could still achieve 66.19% of the control effect as well.Fluorescence microscopy method has the advantages of being intuitive,simple,and easy to operate.Therefore,this paper mainly used fluorescence microscopy to evaluate the effect of spray adjuvant on the erosion of rainwater on azoxystrobin in maize leaves.The results of this study indicate that there is a good correlation between the fluorescence coverage of azoxystrobin as measured by fluorescence microscopy and the retention of azoxystrobin as measured by high performance liquid chromatography.Therefore,the method of selecting fluorescence microscopy to evaluate the retention of azoxystrobin on maize leaves is accurate and reliable.更多还原