Effect of Spray Adjuvants on Wetting and Spreading Behavior of Spinetoram Solution on Mango Leaves
Spinetoram is a common pesticide used to control thrips on mango.The addition of pesticide spray adjuvants can improve the utilization efficacy of the pesticide.Reasonable selection and use of additive products are crucial to improve the utilization efficiency of pesticides and reduce the use of pesticides.In this study,the wetting and spreading behavior of different types of pesticide adjuvants on the surface of mango leaves was investigated by measuring the static and dynamic surface tension,contact angle,spreading area,and evaporation time of spinetoram solution after adding five different types and different concentrations of pesticide adjuvant products.The results showed that adding different adjuvants could effectively reduce the static and dynamic surface tension of the spinetoram solution,reduce the contact angle and increase the spreading area of the solution on the leaf surface.Except polymer adjuvants(Noposion Tiandun)showing evaporation resistance,other adjuvant products shortened the evaporation time.The wettability of different types of adjuvants on mango leaves was not consistent,organosilicone(Jirun)had the best wettability,followed by metal silicate composite salt(Maidao),modified vegetable oil(Maifei),orange peel essential oil(Danluofeng),and polymer(Noposion Tiandun).By comparing the wetting and spreading behavior of different treatments on the front and back of mango leaves,it was found that the back of mango leaves was more difficult to be wetted by pesticide solution than the front.Therefore,the physicochemical properties of the solution and the surface structure of the leaves were important factors affecting the wetting behavior of the spray droplets on the leaves.The mango thrips often feed on the back of the leaves,so in the prevention and control of mango thrips,the appropriate concentration should be selected according to the type of adjuvants and the harm characteristics of thrips to achieve a better control effect.The results revealed the wetting and spreading behavior of different additives on mango leaves and provided data support for the rational use of pesticide adjuvants.