Study And Evaluation Of Water-based Low Volume Thermal Fogging Additive Spraying By Thermal Fogger In Greenhouse

In this paper,the thermal fogger technology was studied,which is a new technology rising in recent years in our country.Using diesel as the carrier of pesticide is convenient,but has poor compatibility with the commercial pesticide,which affect the control effect of plant diseases and pests.So,this paper studied a kind of thermal fogging additive which was based on the technology of thermal fogger,and to evaluate its index like security,as well as the uniformity of the pesticide droplets.The control effect of thermal fogger against plant diseases and pests in green house was also studied..1.The thermal fogging additive is mainly composed by the solvent of thermal fogger,emulsifier,dispersant and settlement agent.The selected solvent of thermal fogger is white oil.And the emulsifier are A4(65%)B4(35%),and the certain proportion is 16%.The chosen dispersion is C1 and the dosage is 3.5%.The settlement agent is E3,and the proportion is 3%.2.The surface tension,viscosity,flash point of the thermal fogging additive were detected and the safety on plant was evaluated.The surface tension of the thermal fogging additive is 35.56 mN/m,comparing with the water’s 77.91 mN/m.The viscosity of the agent is 21.2 mPa s,comparing with the water’s 0 mPa-s,The flash point of the thermal fogging additive is 97℃.In the safety experiment of the plants,the selected plants are cucumber and tomato.Each plant cultivate 3 kinds of varieties.We used thermal fogging additive sprayed by thermal fogger in the stage of young seedling stage,seedling stage,flowering stage and fruit stage,found that in the stage of young seedling stage and seedling stage,it has different degrees of phytotoxicity,while in the stage of flowering and fruit stage,it has no influence,which states that it is safe in the flowering and fruit stage.3.In the paper we compare the deposition and diameter of the droplet between spraying water and thermal fogging additive by thermal fogger.The results show that when the distance from the nozzle are 5m,the deposition of spraying thermal fogging additive are 3.9 times to spray water.Though detecting of particle size shows when spraying thermal fogging additive and spraying water,the middle volume of the droplet were 9.76μm and 40.82μm respectively.4.The results of field trial,show that the field efficacy were 84.1%,94.4%,97.9%by using thermal fogger against Powdery Mildew in Cucumber when the amount of Difenoconazole were 5.0g/667m2,6.7g/667m2,8.3g/667m2,which is much better than the field efficacy of manual sprayer,which were 61.8%,69.3%,74.2%respectively.The field efficacy which were investigate after 7 days of spraying were 62.6%,67.1%and 73.9%by using thermal fogger against the greenhouse whitefly in tomato when the amount of Imidacloprid were 4.0g/667m2,6.0g/667m2,8.0g/667m2,which is also better than the field efficacy of manual sprayer,which were 58.3%,62.4%,65.0%respectively.5.The primary deposit rate of Difenoconazole on the cucumber were 0.0083mg/kg,which is far below maximum residue limits(MRL)(0.10m/kg)formulated by UK/EC.The primary deposit rate of Imidacloprid were 0.193mg/kg when using the method of thermal fogger spraying Imidacloprid against whiteflies on tomatoes,which is far below maximum residue limits(MRL)(0.20m/kg)formulated by UK/EC.The trail results show that using the method of thermal fogger against Powdery Mildew in Cucumber and whitefly in tomato are safe.