Monitoring Of Insecticide Resistance Of Aphis Gossypii From Zanthoxylum Bungeanum In Shaanxi Province

Aphis gossypii(Aphis gossypii Glover),belonging to the Homoptera Aphidae family,is one of the main pests of Zanthoxylum bungeanum.It uses nymphs and adults to harm the tender branches,leaves,flowers,and young fruits of Zanthoxylum bungeanum,causing severe coal pollution,reducing the fruit setting rate of Zanthoxylum bungeanum,and seriously affecting economic returns.Currently,chemical control is the main method for Aphis gossypii in China.With the irrational use of pesticides,confusion in the use of insecticides,and frequent spraying,the level of resistance of the pest to insecticides is gradually increasing,and the difficulty of control is increasing,leading to increasingly poor field control effects.Therefore,this study investigated the occurrence dynamics of Aphis gossypii on Zanthoxylum bungeanum trees in Shaanxi Province and the resistance of different Zanthoxylum bungeanum varieties to Aphis gossypii,measured the sensitivity of field populations of Aphis gossypii to six insecticides in four different Zanthoxylum bungeanum planting areas in Shaanxi Province,and studied the field control effects of commonly used insecticides on Aphis gossypii in Zanthoxylum bungeanum,to determine the level of resistance to Aphis gossypii in different regions,It is hoped to provide a theoretical basis for the scientific control of Aphis gossypii in Zanthoxylum bungeanum and the selection of resistant varieties.The main results are as follows:1.The population dynamics of the Aphis gossypii in the Zanthoxylum bungeanum orchard of Northwest Agricultural and Forestry University were investigated for two consecutive years,and the population dynamics of the Aphis gossypii in the Zanthoxylum bungeanum orchard were preliminarily determined.The results showed that the occurrence dynamics of Aphis gossypii showed a three-peak pattern,with the first peak period of Aphis gossypii occurrence in mid-May,the second peak period of Aphis gossypii occurrence from mid-July to early August,and the third small peak period of Aphis gossypii occurrence from mid-August to the end of August.The occurrence of Aphis gossypii is closely related to various climatic factors such as temperature,rainfall,and air humidity in the current year.2.The field resistance of 16 Zanthoxylum bungeanum varieties to Aphis gossypii was evaluated using the pest index method in Shaanxi Province.The results showed that the results of different resistance evaluations determined by the insect pest index method can better reflect the resistance among varieties.The resistance of 16 Zanthoxylum bungeanum varieties to Aphis gossypii can be divided into 5 categories,namely,stinky Zanthoxylum bungeanum,Xinglong autumn Zanthoxylum bungeanum,and Chaocangshan Zanthoxylum bungeanum are highly susceptible varieties;Bean Zanthoxylum bungeanum,Pingshun Dahongpao,Hanyuan Zanthoxylum bungeanum,Longnan Dahongpao,Chinese wolfberry Zanthoxylum bungeanum,grape Zanthoxylum bungeanum,Maowen Dahongpao,Fengxian Dahongpao,Ruicheng Zanthoxylum bungeanum,Hancheng Dahongpao,and Jiuye green Zanthoxylum bungeanum are sensitive varieties;August Zanthoxylum bungeanum is a medium resistant variety;Raisin Wild Zanthoxylum bungeanum is a resistant variety.3.The resistance level of field populations of Aphis gossypii in Hancheng,Fengxian,Fuping,and Qishan regions of Shaanxi Province was analyzed using the impregnation method.The results showed that the sensitivity of field populations of Aphis gossypii to six insecticides varied among different geographical populations compared to sensitive strains.The resistance multiple of the Aphis gossypii population in Qishan to cypermethrin,imidacloprid,acetamiprid,and chlorpyrifos is low,ranging from 0.60 to 2.19,indicating that the region is still at a sensitive level to the four insecticides mentioned above;The multiple resistance of the Aphis gossypii population in Fuping to the three insecticides of imidacloprid,bifenthrin,and avermectin ranged from 3.02 to 3.92,indicating that the region has developed resistance to the three insecticides,while the resistance to the two insecticides of chlorpyrifos and cypermethrin was low,and the resistance to acetamiprid was moderate;The multiple resistance of the Aphis gossypii population to cyfluthrin,acetamiprid,chlorpyrifos,and abamectin in Fengxian County ranged from 3.34 to4.55,indicating that the region has developed resistance to the above insecticides;The level of resistance of the Aphis gossypii population in Hancheng to insecticides is significantly higher than that in other regions,with resistance multiples ranging from5.81 to 20.40,indicating that the Aphis gossypii population in this region has developed resistance to six insecticides: imidacloprid,acetamiprid,chlorpyrifos,cypermethrin,bifenthrin,and avermectin.4.Through testing the field control effects of seven insecticides against the Aphis gossypii,highly effective insecticides for controlling the Aphis gossypii were selected.The experimental results showed that three insecticides,50% fluazidimefon aqueous dispersion,50% thiamethoxam aqueous dispersion,and 22.4% spirochete suspension,had the best control effects on the Aphis gossypii in Zanthoxylum bungeanum.The average control effects on the cotton aphid after 14 days of treatment were all above88%,significantly higher than those of other treatments.