Preparation Of Composite Microspheres Of Insecticides And Attractants For Control Of Rhagoletis Batava Obseuriosa Kol.

Hippophae rhamnoides L.is a widely distributed species that contributes to soil and water conservation.Its fruits,seeds and leaves are also the raw materials for many healthy products.Rhagoletis batava obseuriosa Kol.?RBO?is the fruit fly pest that damage sea buckthorn berries.In this paper,gelatin and polylactic acid were used as carriers to prepare microspheres containing insecticide?spinosad or abamectin?and attractant?ammonium carbonate?for the attraction and killing of RBO to achieve the purpose of control.The orthogonal test L₁₆?4⁵?was selected to optimize the levels of gelatin,spinosad,ammonium carbonate,polylactic acid and reaction temperature.The optimum conditions for preparing the microspheres were 2 g of gelatin,2 g of spinosad,1.5 g of ammonium carbonate,2 g of polylactic acid,and a reaction temperature of 40?.The average particle size was 55.54?m,the encapsulation efficiency of spinosad was 98.15%,and the encapsulation amount of ammonium carbonate was 2.56 mg/g.The shape of the microspheres was uniform and had a desired sustained release effect.The release time of ammonium carbonate was 10 days,and the spinosad could be released within 15 days.The single factor design was selected to fix the dosage of avermectin,polylactic acid,gelatin and reaction temperature to investigate the effect of different dosage of ammonium carbonate on the physicochemical properties of microspheres.The obtained microspheres were uniform spherical with a porous surface,and an average particle size of 55-78?m.The release rate could be described by the first-order kinetic equation,and the microspheres achieve longer sustained release of insecticides and attractants.The sustained release time of abamectin was about 15 days,and the sustained release time of ammonium carbonate was about 7 days.Toxicity test of abamectin microspheres:in the contact test,there was a significant difference in LT₅₀?median lethal time?between the 4 treatments and the control?F=25.864,df=4,20,P<0.05?.However,there was no significant difference in LT₅₀0 between the 4treatments?F=4.695,df=3,16,P=0.15?;in the stomach toxicity test,there was a significant difference in LT₅₀0 between the 4 groups of treatments and controls?F=44.888,df=4,45,P<0.05?,the toxic effect of the microspheres was about 6-10 times that of the control group.However,there was no significant difference in LT₅₀0 between the 4 treatments?F=2.392,df=3,36,P=0.085?;in the attractiveness test,the average number of RBO trapped with microspheres was 7-15 times that of the control,there was a significant difference in the trapping of RBO between the four treatments and controls?F=8.161,df=4,50,P<0.05?.The number of microspheres trapped with the highest concentration of ammonium carbonate was higher than that of other treatments?F=4.692,df=3,40,P<0.05?.The forest land control experiment by spinosad microspheres:the density of the RBO population decreased significantly.The number of RBO captured in the treatment group?21.20±6.31?was significantly less than that of the control group?130.80±27.54??t=4.936,df=8;P<0.05?.After 15 days of application by drone,the seabuckthorn fruits?16.05%±1.15%?infected with the RBO at the treated site was less than the control site?81.75%±1.50%??t=56.105,df=6;P<0.05?.It showed that the microspheres had a good trapping effect on the RBO.