Study On The Activity Of D-limonene In The Control Of Panonychus Citri McGregor.

P.citri is a kind of polyphagous world-class herbivorous mites,which is harmful in citrus plants,and seriously affect the quality and taste of citrus.In view of the increasing drug resistance of P.citri,d-limonene was used as an object to study the control effect of d-limonene on P.citri,in order to provide a theoretical basis for the use of d-limonene to control tetranychus and reduce the use of chemical pesticides.Firstly,the indoor biological activity of d-limonene against P.citri was determined by different methods.The results showed that eggs were treated by spraying method,and the LC₅₀ at 48 h was 231.73 mg·L^-1.Females were treated with glass slide impregnation and the LC₅₀ of 24 h was 541.07 mg·L^-1.The deutonymph was treated with leaf for 24 h and the LC₅₀ was 630.45 mg·L^-1.The females treated with spray had a EC₅₀ of 54.19 mg L^-11 after 72h.From this we can know that d-limonene acts as a contact,kills eggs,inhibits spawning and stomach poisoning on P.citri.It can be seen that the action of d-limonene on P.citriis contact poisoning,killing eggs,inhibiting spawning and stomach poisoning.Secondly,based on the toxicity of each chemical acaric agent,the combined effect of d-limonene on several important acaricides was studied by cotoxicity factor and cotoxicity coefficient method.The results of glass slide impregnation showed that the LC₅₀ of rotenone,pyridaben,bifenthrin,bifenazate,spirotetramat,cyflumetofen,fluazinam,tolfenpyrad and chlorfenapyr were 184.40,11.27,55.58,16.16,48.33,12.69,141.72,87.74and 14.14 mg·L^-1,respectively.The LC₅₀ of d-limonene and other nine acaricides against P.citri was mixed according to different volume ratio,respectively.And the toxicity of different combinations of insecticides to female adult mites of P.citri was determined by glass slide impregnation method in order to verify the synergism.Lastly,the mathematical model was obtained by using SPSS to fit the adjusted virulence ratio of different combinations to female adult and the percentage content of d-limonene in the compound,and the basic formula was in line with Y=aX²+bX+c,which led to the best synergistic ratio through derivation.Again,after calculating the synergistic ratios of d-limonene and different agents,the optimal mass ratio was obtained from the mathematical model derivation,and the synergy of the best mass ratio compounded combination was determined by the glass slide impregnation method.When the mass ratio of d-limonene to rotenone was 48.67:51.33,the LC₅₀ was 238.82 mg·L^-1,and the CTC was 169.15.When the mass ratio of d-limonene to pyridaben was 49.19:50.81,the LC₅₀ was 14.08 mg·L^-1,and the synergistic multiple was195.03.When the mass ratio of d-limonene to bifenthrin was 50.31:49.69,with the LC₅₀was 59.72 mg·L^-1,and the CTC was 173.91.d-limonene and bifenazate with the mass ratio was 51.63:48.47,the LC₅₀ value was 20.25 mg·L^-1,and the CTC was 154.98.When the mass ratio of d-limonene to spirotetramat was 52.53:47.47,the LC₅₀ value was 47.11mg·L^-1,the CTC was 196.15.When the mass ratio of d-limonene to cyflumetofen was54.55:45.45,LC₅₀ value was 12.13 mg·L^-1,and the CTC was 223.90.When the mass ratio of d-limonene to fluazinam was 47.94:52.06,the LC₅₀ value was 108.43 mg·L^-1,and the CTC was 201.53.And the mass ratio of d-limonene to tolfenpyrad was 50.47:49.53,the LC₅₀ value was 100.92 mg·L^-1,and the CTC was 149.84.When the mass ratio of d-limonene to chlorfenapyr was 50.99:49.01,the LC₅₀ value was 15.09 mg·L^-1,and the CTC was 207.65.Finally,the LC₅₀ of the compounded agent with the best quality ratio was used to control the females of P.citri on the outdoor potted seedlings glass slide impregnation.According to the control effect and the oviposition inhibition rate,the mixture had better effects than the single agent.The control effect and oviposition inhibition rate of d-limonene and rotenone compound mixture was 80.17%and 77.44%at 5 day,and 58.62%and 48.12%for rotenone alone,respectively.The control effect and oviposition inhibition rate of d-limonene and pyridaben compound mixture was 98.28%and 87.88%at the 5 day,while only 73.28%and 59.37%of the pyridaben.The control effect and oviposition inhibition rate of d-limonene and bifenthrin compound mixture was 69.83%and 85.53%at5 day,and 62.07%and 58.27%for bifenthrin.The control effect and oviposition inhibition rate of d-limonene and bifenazate compound mixture was 80.12%and 85.35%on 5 day,while the bifenazate was 71.55%and 56.90%.The control effect and oviposition inhibition rate of d-limonene and spirotetramat complex mixture on P.citri was 100.00%and 93.94%on 5 day,and 93.76%and 30.30%on single spirotetramat.The control effect and oviposition inhibition rate of d-limonene and cyflumetofen compound mixture on P.citri was 97.41%and 87.88%at 5 day,and 50.00%and 54.80%for cyflumetofen alone.d-limonene and fluridone The control effect and oviposition inhibitory rate d-limonene and fluazinam mixed compound was 95.69%and 91.92%at 5 day,and 53.45%and 61.45%for fluazinam alone.The control effect and oviposition inhibition rate of d-limonene and tolfenpyrad compound mixture was 51.72%and 73.62%at 5 days,and 50.00%and 59.16%for tolfenpyrad,respectively.The control effect and oviposition inhibition rate of d-limonene and chlorfenapyr was 96.55%and 93.94%at 5 day,while 80.17%and 61.90%for chlorfenapyr.d-limonene and rotenone,bupropion,butylidril,fluidine were recommended.Amine and insect phthalonitrile compound use.