Studies On The Insecticide Ecology Of Myzus Persicae(Sulzer)

In this paper , the insecticide sensitivity of two different color forms of Myzus Persicae ,naniely red form and green form , and the toxicity of insecticides to Myzus persicae under different temperature were systematically studied And the effect of pesticides to the biology of Myzus persicae were studied to lay a foundation for the pest control in the fields. Experiments were conducted under programmable biociimatic facilities laboratory ,Fujian Provincial Key Laboratory of Entomology Ecology. Several chambers were used for mass rearing in order to obtain the Myzuspersicae cohorts for experimental studies. It dealt with the sensitivity to four insecticides about red and green color forms of Myzus 1?ersicae .The constant environmental conditions were as followings: 250C, 75%R.H. and 14L: lOW The results showed that the lethal concentration of 50% mortality (LC50) to the female adults aphids of red forms and green forms respectively were 4OTh4ppm and 280.4ppm for dimehypo,25l.lppni and 154.9ppm for methomyl, 645.6ppm and 446.7ppm for dimethoate , 2li7ppm and 295.lppm for meothrin .But from the linear regression equations about red forms and green forms to four insecticides we knew that there were no significant differences between the b values of dimehypo and methomyl . there were significant differences between the b values of dimethoate and meothrin .Tbe results will play a very important role in integrated Myzus Persicae management. It dealt with the toxicity of five pesticides to Myzus persiccze under programmable bioclimatic facilities laboratory conditions .The constant environmental conditions were as followings:20?2 0C ,70 ?5%RJ-Land 14L:lO]YResults indicated that the toxicity of four pesticides ,namely omethoate,triazophos, dimehypo and methomyl to Myzus persicae increased with the temperature going up The relationship between probit of mortalities(y) and temperatures(s) respectively were : r3.0738+0.0695x y=2.9821+0.0852x, y=4.l l06+0.0500x, and y=4.36l l+OA)460x, while that of Decis declined , y=6.9422-0.0862x. The toxicities of three insecticides to the feniaie adults of Mykit~ p鑢sicae at different temperatures were also studied. From 15℃ to 35℃ the liner regression equations for the LC50 of different insecticides (y) under various temperature (x) were y4239.855-30.1568x for methamfdopho, y=463.3354-5.1682x isoprocarb, y=l 19.942-3.023 lx cypermethrin .These results laid a foundation for using insecticides with proper concentration. The toxicity of mixed insecticides to the aphids was studied .Jt was indicated that under the following conditions, 20-32℃ ,7±5%R.H.and l4L: 1OD,the toxicity was enhanced when the mixed ratio of methamidopho to isoprocarb was 7:3 or 9:1 under theft common concentrations used in the fields, or when the mixed ratio of methamidopho to cypermethrin was 7:3 ,while the toxicity was declined at any studied ratio of isoprocarb to cypermethrin .S6the 7proper ratio of mixed insecticides will play a very important role in the pest control in the fields. The effect of pesticides to the biology of Myzus persicae was studied in the nature conditions . It was found that at 17.9℃ methamidophos ,triazophos, isoprocarb, dimehypo , cypermethrin and decis did not stimulate the fertility of Myzus persiccte under concentrations commonly applied in the fields Thiophanatemethyl , mengfeiling, carbendazim and yeqingshuang didn't cause any difference in the longevity of the female adults and fertility of gre...