Resistance Examination Of Myzus Persicae(Sulzer) And Primary Studies On Resistance Mechanism

The purpose of this paper is to examine the resistance of Myzuspersicae(Sulzer) in main planting tobacco areas of ourcountry.Besides, resistance mechanism is also an importantpurpose.Then the toxicity of fenvalerate, omethoate, methomyl andimidacloprid is studied in different tempetatures. The resistantdiffereance of Myzus persicae(Sulzer) in different hosts and itsresistant mechanism are studied.The result that could be summariedis ao follows:1,The susceptibility of Myzus persicae(Sulzer) from main plantingtobacco areas of our country to four insecticides was tested withtopical application recommended by FAO.Based on LD50 values,theresult showed that the order of susceptibility of Myzuspersicae(Sulzer) to fenvalerate, omethoate, methomyl andimidacloprid was fenvalerate﹥omethoate﹥imidacloprid﹥methomyl.According to LD50 values of Myzus persicae(Sulzer),the toxicityorder of fenvalerate is Bengbu of Anhui, Suzhou of Anhui,Sanmingof Fujian,Chuxiong of Yunnan,Dali of Yunnan,Changle ofShandong,Wuhu of Anhui,all of which are the five most serious inresistance,respectively being 56.4 folds,36.15 folds ,31.56folds,26.87 folds,24.98 folds to sensitive popolation; the toxicityorder of omethoate is Wuhu of Anhui,Changle of Shandong,Sanming ofFujian and Chuxiong of Yunnan, all of which are the five most seriousin resistance,respectively being 30.75 folds,16.35 folds ,14.85folds and 10.02 folds to sensitive popolation; the toxicity orderof methomyl is Suzhou of Anhui,Chuxiong of Yunnan,Dali of Yunnanand Wuhu of Anhui, all of which are the five most serious inresistance,respectively being 7.07 folds,6.00 folds,5.21 folds and5.00 folds to sensitive population; the toxicity order ofimidacloprid is Sanming of Fujian,Bengbu of Anhui,Longquan ofFujian,Binxian of Heilongjiang and Wuhu of Anhui, all of which arethe five most serious in resistance, respectively being 32.85folds,16.94 folds ,11.81 folds,10.03 folds and 10.02 folds tosensitive population.2,Studies on the effect of synergists on the toxicity of commonlyused insecticides to resistant aphids indicated that mixed functionoxidase(MFO) system may be the major enzyme system.In addition,theresistance of the tobacco aphid may be related to the increasedactivities of the enzyme system including carboxylesterase(CarE)and acetylcholinesterase(AchE) insentivity. The zymogram ofesterase isodyna electrophores is demonstrated that susceptiblestrain and resistance strain both have the same enzyme bands.Thedifference of the color on the bands shows that the resistance ofMyzus persicae(Sulzer) is concerned with the change of esterase.3,The toxicity of three insecticides to the female adults of Myzuspersicae(Sulzer) at different temperatures were also studied.From21℃to 33℃,the relation between toxicity and temperature ispositive.As for imidacloprid,the toxicity of 21℃is 16.89 foldsto the toxicity of 33℃; As for omethoate,the toxicity of 21℃is3.81 folds to the toxicity of 33℃; As for methomyl,the toxicityof 21℃is 2.625 folds to the toxicity of 33℃.These results laida foundation for using insecticides with proper concentration.4,The susceptibility of Myzus persicae(Sulzer) to four insecticidesis affected by Myzus persicae(Sulzer) feeding on different hostplant markedly.The toxicity order is cabbage strain,tobacco strain...