4种药剂对沙棘绕实蝇成虫的触杀活性

目的]沙棘绕实蝇在我国新疆和内蒙古地区对沙棘果实造成重大危害,如何选取高效、易降解、低残留的农药种类成为当前沙棘绕实蝇成虫防控工作中的迫切课题。方法]野外采集沙棘绕实蝇蛹,室内待其羽化后,雌、雄分组放置于不同浓度梯度的4种农药条件下进行触杀实验。结果]通过KT_(50)(median knockdown time)的数据分析结果显示,同种农药同种浓度时,药物对雄性的触杀效果比雌性强,其中苦参碱在浓度为0.005 mg·m L~(-1)时,雄性KT_(50)值为39.21 h,小于雌性KT_(50)值56.13 h,但个别情况下出现对雌性触杀效果比雄性高的情况,如苦参碱在浓度为0.05 mg·m L~(-1)时,雄性KT_(50)值为15.76 h,大于雌性KT_(50)值12.39 h。通过测定4种农药对沙棘绕实蝇成虫的致死中浓度LC_(50)(median lethal dose),得出触杀作用时间为12 h时,LC_(50)分别为:印楝素7.737 mg·m L~(-1)、高效氯氟氰菊酯0.002 mg·m L~(-1)、苦参碱0.042 mg·m L~(-1)、阿维菌素0.008 mg·m L~(-1),其触杀毒力次序为:高效氯氟氰菊酯阿维菌素苦参碱印楝素;触杀作用时间为24 h时,LC_(50)分别为:印楝素6.963 mg·m L~(-1)、高效氯氟氰菊酯0.001 mg·m L~(-1)、苦参碱0.008 mg·m L~(-1)、阿维菌素0.001 mg·m L~(-1),其触杀毒力次序为:阿维菌素高效氯氟氰菊酯苦参碱印楝素;触杀作用时间为48 h时,LC_(50)分别为:印楝素0.891 mg·m L~(-1)、高效氯氟氰菊酯0.001mg·m L~(-1)、苦参碱0.002 mg·m L~(-1)、阿维菌素0.001 mg·m L~(-1),其触杀毒力次序为:阿维菌素=高效氯氟氰菊酯苦参碱印楝素。结论]阿维菌素和高效氯氟氰菊酯对沙棘绕实成虫的触杀效果较显著,其次为苦参碱,印楝素的触杀效果不显著。

Contact Lethal Activity of Four Environmental Friendly Pesticides to Rhagoletis batava obseuriosa Diptera: Tephritidae) Adults, A Serious Fruit Fly of Seabuckthorn

Objective] Rhagoletis batava obseuriosa (RBO) has caused serious damage to Hippophae rhamnoides fruit in Dengkou County, Inner Mongolia, China. This study aims at Selecting high efficiency, low residue and easy degradable environmental friendly pesticides to prevent and control RBO.Method] The pupae of RBO were collected at sea-buckthorn orchard in Dengkou County in April, 2017. After the emergence of adults in the laboratory, the female and male adults were separately bioassayed with different concentrations of four pesticides to evaluate the contact lethal effects of the four pesticides by dish tests.Result] The results of KT₅₀ (median knockdown time) data analysis showed that the male''s contact toxicity of four pesticides was a little higher than that of female. When the concentration of matrine was 0.005 mg·mL^-1, the male''s KT₅₀ value was 39.21 h, less than the female''s KT₅₀ value of 56.13 h, but there was some exceptions, for example, when the concentration of matrine was 0.05 mg·mL^-1, the male''s KT₅₀ value (15.76 h) was higher than the female''s KT₅₀ value of 12.39 h. The results of LC₅₀ (median lethal dose) analysis showed that the contact toxicity of four pesticides to RRO was different. When the adults were treated with 12 hours, LC₅₀ of the four different pesticides were azadirachtin 7.737 mg·mL^-1, lambda-cyhalothrin 0.002 mg·mL^-1, matrine 0.042 mg·mL^-1 and avermectins 0.008 mg·mL^-1, respectively. The lethal effect of the four pesticides from high to low were lambda-cyhalothrin, avermectins, matrine and azadirachtin; when the adults were treated with 24 hours, LC₅₀ of four pesticides were azadirachtin 6.963 mg·mL^-1, lambda-cyhalothrin 0.001 mg·mL^-1, matrine 0.008 mg·mL^-1 and avermectins 0 mg·mL^-1, respectively. The lethal effects from high to low were avermectins, lambda-cyhalothrin, matrine and azadirachtin; when adults were treated with 48 hours:LC₅₀ of four pesticides were azadirachtin 0.891 mg·mL^-1, lambda-cyhalothrin 0 mg·mL^-1, matrine 0.002 mg·mL^-1 and avermectins 0 mg·mL^-1, respectively. The lethal effects of the four pesticides from high to low were avermectins, lambda-cyhalothrin, matrine and azadirachtin.Conclusion] Avermectins and lambda-cyhalothrin have high contact lethal effect to RBO adults, followed by matrine. Azadirachtin shows no effective contact lethal ability to RBO adults. More bioassay need to be carried to check their control effect on RBO in the field.