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Abstract [Objectives]The aim was to screen the insecticides with significant control effect on Ectropis oblique by comparing the control efficiency of different insecticides.
[Methods]A series of indoor bioassay tests were conducted using 9 different insecticides， namely， Spinetoram， Azadirachtin， Flubendiamide， Emamectin benzoate， Methoxyfenozide， Chlorbenzuron， Rotenone， Matrine， Bifenthrin.
[Results]The corrected control efficiency after 7 d application was the best when using Spinetoram， which was 93.96%， and the corrected control efficiencies of other insecticides from high to low were in the order of Methoxyfenozide， Emamectin benzoate， Azadirachtin， Bifenthrin， Matrine， Chlorbenzuron， Flubendiamide， Rotenone， of 89.15， 85.54， 84.35， 81.93， 79.51， 53.02， 50.59， 24.10%， respectively.
[Conclusions]This study provided theoretical bases for the scientific control of E. oblique.
Key words Ectropis oblique； Insecticide； Control
Ectropis oblique Prout， a member of Geometridae of Lepidoptera， is an important pest of tea trees which seriously damages tea gardens in Jiangsu， Zhejiang， Jiangxi， and Hunan[1]. E. oblique usually damages the hilly tea gardens with high shoot tendernesskeeping ability， moist and closed conditions， leeward and sunexposed locations and single tea species[2]. It can have 6-7 generations throughout the year. The first generation occurs in early April， and then each generation occurs every one or half a month. In early autumn， if the temperature is high and precipitation is sufficient， the 7th generation may easily occurs[3].
The comprehensive field control of E. oblique is mainly achieved through the breeding of resistant varieties[4-7]， rational planting layout[8-9]， light trapping adult pests[10-12]， utilization of microorganisms and natural enemy insects[13-16]， and chemical control. The ideal goal of tea garden management is to continuously control the population density of insect pests at a relatively low level using the selfregulatory capacity of the tea garden ecosystem. However， since there is a possibility of a large outbreak of E. oblique， it is necessary to use chemical control to achieve rapid reduction of insect population density. In this study， the method of indoor toxicity measurement was used to compare the control effects of different insecticides on E. oblique to screen out the effective insecticide for E. oblique control， so as to provide a theoretical basis for the scientific prevention and treatment of E. oblique. Materials and Methods
Materials
Test insecticides
The insecticides used in the test are shown in Table 1.
Test insect
In April 2017， E. oblique was collected in the tea garden of Changsha County， and was reared on fresh leaves. When the 2nd generation grew to 3 instars， healthy and lively larvae were selected for testing.
Test treatment
A total of 10 treatments were set， namely， 3 000 times diluted 60 g/L Spinetoram suspension agent， 1 000 times diluted solution of 0.5% Azadirachtin microemulsion， 6 000 times diluted 20% Flubendiamide water dispersible granule， 15 000 times diluted 3% Emamectin benzoate microemulsion， 5 000 times diluted 240 g/L Methoxyfenozide suspension agent， 3 000 times diluted 20% Chlorbenzuron suspension agent， 1 000 times diluted 2.5% Rotenone missible oil， 1 000 times diluted 0.3% Matrine water aqua， 3 000 times diluted 100 g/L Bifenthrin emulsion in water and the blank control （distilled water）. Each treatment had 3 repetitions， an so there were a total of 30 indoor trial treatments. Tea branch water planting method was used. The prepared insecticides were sprayed evenly to the branches and leaves on both sides using a sprayer， and when the liquid was dry， 30 3install pests were inoculated， during which the water was replenished to the triangular flask as required to avoid tea branches wilting due to lack of water. Investigations were made 3 and 7 d after insecticide application. The number of dead insects， live insects were counted to calculate the population decline rate and control efficacy.
Data processing
Insect population decline rate∥% = （Number of live insects before insecticide applicationNumber of live insects after insecticide application） / Number of live insect before insecticide application × 100
Corrected control efficacy∥% = （Insect decline rate in the treatment area ± Insect decline rate in the control area） / （1-Insect decline rate in the control area） × 100
SPSS19.0 software was used for data analysis.
Results and Analysis
As shown in Table 2， the population decline rate and corrected control efficacy were the highest at 3 d after the application of Methoxyfenozide， and the decline rate was 70%， corrected control efficacy 68.97%. The population decline rate and corrected control efficacy were the lowest at 3 d after the application of rotenone. The population decline rate was only 6.67% and the corrected control efficacy was 3.46%. After 3 d of application， the insect population decline rate and corrected control efficiency of the tested insecticides from high to low were in the order of Methoxyfenozide， Spinetoram， Emamectin benzoate， Azadirachtin， Flubendiamide， Matrine， Bifenthrin， Chlorbenzuron， and Rotenone， with the decline rate of 70.00%， 66.67%， 63.33%， 60.00%， 43.33%， 43.33%， 23.33%， 13.33%， and 6.67%， respectively， and corrected control efficacy of 68.97%， 65.52%， 62.07%， 58.58%， 41.38%， 41.38%， 20.69%， 10.34%， and 3.46%， respectively. After 7 d of application， the insect population decline rate and corrected control effect were found in the treatment with Spinetoram， 94.43% and 93.96%， respectively. The population decline rate and corrected control efficacy were the lowest at 7 d after the application of rotenone， 6.67% and 3.46%， respectively. After 7 d of application， the insect population decline rate and corrected control efficiency of the tested insecticides from high to low were in the order of Spinetoram， Methoxyfenozide， Emamectin benzoate， Azadirachtin， Bifenthrin， Matrine， Chlorbenzuron， Flubendiamide， and Rotenone， with the decline rate of 94.43%， 90.00%， 86.67%， 85.57%， 83.33%， 81.10%， 56.67%， 54.43%， and 30.00%， respectively， and corrected control efficacy of 93.96%， 89.15%， 85.54%， 84.35%， 81.93%， 79.51%， 53.02%， 50.59%， and 24.10%， respectively.
As shown in Fig. 1 & 2， the control efficacy of each insecticide after 7 d of application was much better than that after 3 d， and the efficacies of Chlorbenzuron， Rotenone and Bifenthrin increased significantly.
Conclusion
The test results show that E. oblique can be effectively controlled through chemical control methods， and the control efficacies of Spinetoram， Azadirachtin， Emamectin benzoate， Methoxyfenozide， Bifenthrin can reach more than 80%. E. oblique can develop resistance to an insecticide after longterm application， and the efficacy of the laterphase application of the insecticide will be greatly reduced， while the rotation of insecticides can reasonably slow the development of insecticide resistance. In the actual production process， tea producers must reasonably select highefficiency， lowtoxicity， lowresidue insecticides according to the positioning of their products.
Peiyuan RAO. Control Efficiency of 9 Kinds of Insecticides on Ectropis oblique Prout
References
[1]TAN JC. Tea pests and diseases control[M]. Beijing： China Agriculture Press， 2011
[2]XIA YS. The occurrence habits and measures of controlling tea geometrid[J]. Tea in Fujian， 1999， 4：12.
[3]GE F. Modern ecology[M]. Beijing： Science Press， 2002.
[4]YANG LL. Preliminary study on the resistance mechanism of tea tree cultivars to tea leaf spot and tea planthopper[D]. Hefei： Anhui Agricultural University， 2009.
[5]TAN JC. Tea pests and diseases control[H]. Beijing： China Agricultural Press， 2002.
[6]ZHANG WH， LIU GJ. A review on plant secondary substances in plant resistance to insect pests[J]. Chinese Bulletin of Botany，2003，20（5）： 522-530. [7]HU C， ZHAO QQ， ZHENG RL. The larval parasites of the tea geometrid Ectropis oblique hypulina Wehrli[J]. Acta Entomologica Sinica， 1979，22（4）：413-419.
[8]LI ZX， WANG JW， YANG WT， et al. Benefit of sweet corn/soybean intercropping in Guangdong Provnince[J]. Chinese Journal of EcoAgriculture， 2010， 18（3）： 627-631.
[9]PENG P， LI PW， HOU YJ， et al. Study on the diversity of insect communities in tea gardens of different ecological types[J]. Plant Protection， 2006， 32（4）： 67-70.
[10]LIAO MF. The Occurrence and nonenvironmental control techniques of tea geometrids in the teaproducing region of North Fujian[J]. Tea Science and Technology， 2007， 4：39-42.
[11]LIU HM， SUN JY， YANG GX. Integrated treatment technology of tea pests in Xinyang[J]. Guangdong Agricultural Sciences， 2010， 1： 17-22.
[12]SHI CH， YU YJ. Nonpolluted tea production technology[M]. Beijing： China Agricultural Press， 2003.
[13]LV WM， LOU YF， HU HJ， et al. Resistances of different varieties of tea tree to Boarmia oblique hypulina Wehrili[J]. China Tea， 1990， 28（3）： 27-30.
[14]LAI YP， ZHANG DF. Progress of the application study on Beauveria bassiana and Metarhizium anisopliae to control agricultural pests[J]. Science and Technology of Qinghai Agriculture and Forestry， 2011， （1）： 40-42.
[15]AMINAEE MM， ZARE R， ASSARI MJ. Isolation and Selection of virulent isolates of Beauvetia bassiana for biological control of Ommatissus Lybicus in Kerman province[J]. Archives of Phytopathology and Plant Protection， 2010， 43（8）：761-768.
[16]MAHMOUD MF. Pathogenicity of three commercial products of entomopathogenic Fungi， Beauveria bassiana， Metarhizum anisopilae and Lecanicillitrrn lecanii Against adults of olive fly， Bactrocera oleae （Gmelin） （Diptera： Tephritidae） in the laboratory[J]. Plant Protection Science， 2009， 45（3）： 98-102.
Editor： Na LI Proofreader： Xinxiu ZHU
[Methods]A series of indoor bioassay tests were conducted using 9 different insecticides， namely， Spinetoram， Azadirachtin， Flubendiamide， Emamectin benzoate， Methoxyfenozide， Chlorbenzuron， Rotenone， Matrine， Bifenthrin.
[Results]The corrected control efficiency after 7 d application was the best when using Spinetoram， which was 93.96%， and the corrected control efficiencies of other insecticides from high to low were in the order of Methoxyfenozide， Emamectin benzoate， Azadirachtin， Bifenthrin， Matrine， Chlorbenzuron， Flubendiamide， Rotenone， of 89.15， 85.54， 84.35， 81.93， 79.51， 53.02， 50.59， 24.10%， respectively.
[Conclusions]This study provided theoretical bases for the scientific control of E. oblique.
Key words Ectropis oblique； Insecticide； Control
Ectropis oblique Prout， a member of Geometridae of Lepidoptera， is an important pest of tea trees which seriously damages tea gardens in Jiangsu， Zhejiang， Jiangxi， and Hunan[1]. E. oblique usually damages the hilly tea gardens with high shoot tendernesskeeping ability， moist and closed conditions， leeward and sunexposed locations and single tea species[2]. It can have 6-7 generations throughout the year. The first generation occurs in early April， and then each generation occurs every one or half a month. In early autumn， if the temperature is high and precipitation is sufficient， the 7th generation may easily occurs[3].
The comprehensive field control of E. oblique is mainly achieved through the breeding of resistant varieties[4-7]， rational planting layout[8-9]， light trapping adult pests[10-12]， utilization of microorganisms and natural enemy insects[13-16]， and chemical control. The ideal goal of tea garden management is to continuously control the population density of insect pests at a relatively low level using the selfregulatory capacity of the tea garden ecosystem. However， since there is a possibility of a large outbreak of E. oblique， it is necessary to use chemical control to achieve rapid reduction of insect population density. In this study， the method of indoor toxicity measurement was used to compare the control effects of different insecticides on E. oblique to screen out the effective insecticide for E. oblique control， so as to provide a theoretical basis for the scientific prevention and treatment of E. oblique. Materials and Methods
Materials
Test insecticides
The insecticides used in the test are shown in Table 1.
Test insect
In April 2017， E. oblique was collected in the tea garden of Changsha County， and was reared on fresh leaves. When the 2nd generation grew to 3 instars， healthy and lively larvae were selected for testing.
Test treatment
A total of 10 treatments were set， namely， 3 000 times diluted 60 g/L Spinetoram suspension agent， 1 000 times diluted solution of 0.5% Azadirachtin microemulsion， 6 000 times diluted 20% Flubendiamide water dispersible granule， 15 000 times diluted 3% Emamectin benzoate microemulsion， 5 000 times diluted 240 g/L Methoxyfenozide suspension agent， 3 000 times diluted 20% Chlorbenzuron suspension agent， 1 000 times diluted 2.5% Rotenone missible oil， 1 000 times diluted 0.3% Matrine water aqua， 3 000 times diluted 100 g/L Bifenthrin emulsion in water and the blank control （distilled water）. Each treatment had 3 repetitions， an so there were a total of 30 indoor trial treatments. Tea branch water planting method was used. The prepared insecticides were sprayed evenly to the branches and leaves on both sides using a sprayer， and when the liquid was dry， 30 3install pests were inoculated， during which the water was replenished to the triangular flask as required to avoid tea branches wilting due to lack of water. Investigations were made 3 and 7 d after insecticide application. The number of dead insects， live insects were counted to calculate the population decline rate and control efficacy.
Data processing
Insect population decline rate∥% = （Number of live insects before insecticide applicationNumber of live insects after insecticide application） / Number of live insect before insecticide application × 100
Corrected control efficacy∥% = （Insect decline rate in the treatment area ± Insect decline rate in the control area） / （1-Insect decline rate in the control area） × 100
SPSS19.0 software was used for data analysis.
Results and Analysis
As shown in Table 2， the population decline rate and corrected control efficacy were the highest at 3 d after the application of Methoxyfenozide， and the decline rate was 70%， corrected control efficacy 68.97%. The population decline rate and corrected control efficacy were the lowest at 3 d after the application of rotenone. The population decline rate was only 6.67% and the corrected control efficacy was 3.46%. After 3 d of application， the insect population decline rate and corrected control efficiency of the tested insecticides from high to low were in the order of Methoxyfenozide， Spinetoram， Emamectin benzoate， Azadirachtin， Flubendiamide， Matrine， Bifenthrin， Chlorbenzuron， and Rotenone， with the decline rate of 70.00%， 66.67%， 63.33%， 60.00%， 43.33%， 43.33%， 23.33%， 13.33%， and 6.67%， respectively， and corrected control efficacy of 68.97%， 65.52%， 62.07%， 58.58%， 41.38%， 41.38%， 20.69%， 10.34%， and 3.46%， respectively. After 7 d of application， the insect population decline rate and corrected control effect were found in the treatment with Spinetoram， 94.43% and 93.96%， respectively. The population decline rate and corrected control efficacy were the lowest at 7 d after the application of rotenone， 6.67% and 3.46%， respectively. After 7 d of application， the insect population decline rate and corrected control efficiency of the tested insecticides from high to low were in the order of Spinetoram， Methoxyfenozide， Emamectin benzoate， Azadirachtin， Bifenthrin， Matrine， Chlorbenzuron， Flubendiamide， and Rotenone， with the decline rate of 94.43%， 90.00%， 86.67%， 85.57%， 83.33%， 81.10%， 56.67%， 54.43%， and 30.00%， respectively， and corrected control efficacy of 93.96%， 89.15%， 85.54%， 84.35%， 81.93%， 79.51%， 53.02%， 50.59%， and 24.10%， respectively.
As shown in Fig. 1 & 2， the control efficacy of each insecticide after 7 d of application was much better than that after 3 d， and the efficacies of Chlorbenzuron， Rotenone and Bifenthrin increased significantly.
Conclusion
The test results show that E. oblique can be effectively controlled through chemical control methods， and the control efficacies of Spinetoram， Azadirachtin， Emamectin benzoate， Methoxyfenozide， Bifenthrin can reach more than 80%. E. oblique can develop resistance to an insecticide after longterm application， and the efficacy of the laterphase application of the insecticide will be greatly reduced， while the rotation of insecticides can reasonably slow the development of insecticide resistance. In the actual production process， tea producers must reasonably select highefficiency， lowtoxicity， lowresidue insecticides according to the positioning of their products.
Peiyuan RAO. Control Efficiency of 9 Kinds of Insecticides on Ectropis oblique Prout
References
[1]TAN JC. Tea pests and diseases control[M]. Beijing： China Agriculture Press， 2011
[2]XIA YS. The occurrence habits and measures of controlling tea geometrid[J]. Tea in Fujian， 1999， 4：12.
[3]GE F. Modern ecology[M]. Beijing： Science Press， 2002.
[4]YANG LL. Preliminary study on the resistance mechanism of tea tree cultivars to tea leaf spot and tea planthopper[D]. Hefei： Anhui Agricultural University， 2009.
[5]TAN JC. Tea pests and diseases control[H]. Beijing： China Agricultural Press， 2002.
[6]ZHANG WH， LIU GJ. A review on plant secondary substances in plant resistance to insect pests[J]. Chinese Bulletin of Botany，2003，20（5）： 522-530. [7]HU C， ZHAO QQ， ZHENG RL. The larval parasites of the tea geometrid Ectropis oblique hypulina Wehrli[J]. Acta Entomologica Sinica， 1979，22（4）：413-419.
[8]LI ZX， WANG JW， YANG WT， et al. Benefit of sweet corn/soybean intercropping in Guangdong Provnince[J]. Chinese Journal of EcoAgriculture， 2010， 18（3）： 627-631.
[9]PENG P， LI PW， HOU YJ， et al. Study on the diversity of insect communities in tea gardens of different ecological types[J]. Plant Protection， 2006， 32（4）： 67-70.
[10]LIAO MF. The Occurrence and nonenvironmental control techniques of tea geometrids in the teaproducing region of North Fujian[J]. Tea Science and Technology， 2007， 4：39-42.
[11]LIU HM， SUN JY， YANG GX. Integrated treatment technology of tea pests in Xinyang[J]. Guangdong Agricultural Sciences， 2010， 1： 17-22.
[12]SHI CH， YU YJ. Nonpolluted tea production technology[M]. Beijing： China Agricultural Press， 2003.
[13]LV WM， LOU YF， HU HJ， et al. Resistances of different varieties of tea tree to Boarmia oblique hypulina Wehrili[J]. China Tea， 1990， 28（3）： 27-30.
[14]LAI YP， ZHANG DF. Progress of the application study on Beauveria bassiana and Metarhizium anisopliae to control agricultural pests[J]. Science and Technology of Qinghai Agriculture and Forestry， 2011， （1）： 40-42.
[15]AMINAEE MM， ZARE R， ASSARI MJ. Isolation and Selection of virulent isolates of Beauvetia bassiana for biological control of Ommatissus Lybicus in Kerman province[J]. Archives of Phytopathology and Plant Protection， 2010， 43（8）：761-768.
[16]MAHMOUD MF. Pathogenicity of three commercial products of entomopathogenic Fungi， Beauveria bassiana， Metarhizum anisopilae and Lecanicillitrrn lecanii Against adults of olive fly， Bactrocera oleae （Gmelin） （Diptera： Tephritidae） in the laboratory[J]. Plant Protection Science， 2009， 45（3）： 98-102.
Editor： Na LI Proofreader： Xinxiu ZHU