| In recent years,affected by macro factors,when pesticide application reduced but efficiency increased,and labor-saving operation deeply rooted among the people,the demand of publics for labor-saving pesticide formulation has been increasing,resulting in the emergence of new labor-saving pesticide formulation such as large granule agent,dispersible liquid agent,tablet and water surface spreading oil.Spreading oil potion bottle was placed above the rice field when used,and the agentia dropped from the dripping hole by itself,and dispersed naturally on the water surface,quickly covering the whole water surface of the rice field.The membrane could float on the water surface for a long time and effectively prevent disease during the growth of rice plants.In this study,the toxicity of azoxystrobin and thifluzamide single agents were determined by rice sheath blight in mixtures of different proportions.When proportionon of azoxystrobin and thifluzamide was 1:1,the optimal mixture ratio was selected,and the EC50 was 0.0065μg/m L.It was far lower than the baseline of azoxystrobin and thifluzamide sensitivity of rice sheath blight in Liaoning province,which were 0.2322±0.0209μg/m L and 0.4055±0.0309μg/m L respectively.The results showed that the combination of azoxystrobin and thifluzamide could effectively prevent and control the occurrence and spread of rice sheath blight and delay the emergence of resistance.In this experiment,we found that the sensitivity of rice sheath blight to azoxystrobin and thifluzamide was different between different rice planting areas.The strains collected from Panjin city and Liaoyang city showed the strongest sensitivity to azoxystrobin and thifluzamide,which may be caused by the different planting patterns and varieties of rice in the region.In addition,the strain of Yanfeng 47,a rice variety,was the most sensitive to rice sheath blight,possibly because the strain collected was a binucleus strain.In order to serve the farmers better and improve the efficacy of the product,we carried out formulation development of thifluzamide+azoxystrobin 4%spreading oil,aiming to make the formulation of thifluzamide+azoxystrobin 4%spreading oil with more stability and more prominent effect through screening various safe solvents and surfactants.Based on thifluzamide and azoxystrobin as the effective components,by screening the solvents and surfactants,we determined the optimal formulation of thifluzamide+azoxystrobin 4%spreading oil:thifluzamide 2%,azoxystrobin 2%,ethylene glycol tert-butyl ether 5%,coalescing agents 1812 5%,4206#2%,601#2%,added solvent(methyl oleate:150#solvent oil was 2:1)to 100%.All the quality control technical indexes of the thifluzamide azoxystrobin 4%spreading oil were qualified,and the field efficacy test of the formulation was conducted.To verify its effect,the field control experiments of azoxystrobin and thifluzamide 4%spreading oil to the rice sheath blight were started in Panjin Hu Jia Town,Liaoyang tong town,Yingkou city Shi Fo Town and Donggang town,where two pieces of field were chosen,and the prevention and treatment effects of different application periods,times,doses,formulations and components were compared.When azoxystrobin and thifluzamide 4%spreading oil effective dose was 125 g.a.i/hm~2,and the use frequency was once,the control effect of rice sheath blight was higher than azoxystrobin and thifluzamide 25%SC.The control effect of the mixture was 16.8%～20.0%,12.2%～17.7%,14.2%～17.3%higher than that of the other treatments,which were jinggangmeisu,thifluzamide and azoxystrobin,respectively.and the yield of the film spreading oil treatment group was 3.6%～19.0%higher than that of the other treatments.The yield of azoxystrobin and thifluzamide 4%spreading oil treatment group was 3.6%～19.0%higher than that of other treatments.From above all,azoxystrobin and thifluzamide 4%spreading oil had many advantages such as better control effect,longer duration of validity,saving time,and so on. |
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