Seasonal changes of resistance to fenvalerate and cypermethrin in the larval parasitoid Cotesia plutellae （Hymenoptera： Braconidae）

在 hymenopteranCotesia plutellae 的杀虫药剂抵抗和稳定性的季节的变化，从 Jianxin， Fuzhou 城市，和 Shangjie 镇定， Minhou 县，福建，中国，被使用一个干燥剩余电影方法估计。抵抗到在 C 的地人口的二杀虫药剂。plutellae 不在在养虫室的没有杀虫药剂的条件下面是稳定的。与 C 的易受影响的 F_(11 ) 子孙相比。在养虫室的 plutellae ，在 F_0 父母的抵抗比率( RR )为氰戊菊酯是 18.4 并且 11.4 为氯氰菊酯基于在 9 个小时的LC_( 50 )，并且 32.8 为氰戊菊酯并且 28.5 分别地在 第9a 24 个小时为基于在 24 点的LC_( 50 )， theparasitoids 是左的在的小时与杀虫药剂联系 1 个小时和死亡的氯氰菊酯被记录。然而，在 C 的一张地人口的 RR。plutellae 是 9.2 forfenvalerate 并且 12.7 为氯氰菊酯，如果 parasitoids 在与杀虫药剂的接触是左的 24 个小时了。到在另外的地人口的二 pyrethroids 的电阻从 2000 年 11 月收集了 fromJianxin 和 Shangjie， 2004 年 7 月也被决定。到在 C 的地人口的二杀虫药剂的抵抗的重要季节变化。plutellae 被发现。RR 是 3.0—18.4 为氰戊菊酯并且 4.8—20.6 为在到 2002 年 4 月的从 2000 年 11 月的 Jianxin 人口的氯氰菊酯基于在为在到 2004 年 7 月的从 2002 年 5 月的 Shangjie 人口的氰戊菊酯和 3.6-16.0for 氯氰菊酯的 9 h，和 2.3-13.6 的 LC_(50 ) 基于在 24 个小时的 LC_(50 ) 。抵抗层次在春天和秋天高并且在夏天严厉地减少了。另外，重要恢复从组合式由杀虫药剂引起了在 F_0 和 C 的地人口被发现。如果 parasitoidswere 在与 pyrethroids 的接触离开了 1 个小时，对氰戊菊酯和氯氰菊酯抵抗的 plutellae。然而，没有恢复在 susceptibleF_(11 ) 被发现子孙。

The seasonal changes of insecticide resistance and stability in hymenopteran Cotesia plutellae, collected from Jianxin, Fuzhou-City, and Shangjie, Minhou-County, Fujian, China, were assessed by using a dry residual film method. The resistance to two insecticides in the field populations of C. plutellae was not stable under insecticide-free conditions in the insectarium. Compared with susceptible F11 progeny of C. plutellae in the insectarium, the resistance ratios （RR） in F0 parents were 18.4 for fenvalerate and 11.4 for cypermethrin based on LC50 at 9 hours, and 32.8 for fenvalerate and 28.5 for cypermethrin based on LC50 at 24 hours when the parasitoids were left in contact with the insecticides for 1 hour and mortalities were recorded at 9 and 24 hours, respectively. However, the RR in a field population of C. plutellae were 9.2 for fenvalerate and 12.7 for cypermethrin, if the parasitoids were left in contact with the insecticides for 24 hours. The resistances to the two pyrethroids in other field populations collected from Jianxin and Shangjie from November 2000 and July 2004 were also determined. Significant seasonal variations of resistance to the two insecticides in the field populations of C. plutellae were found. The RR were 3.0-18.4 for fenvalerate and 4.8-20.6 for cypermethrin in Jianxin populations from November 2000 to April 2002 based on LC50 at 9 h, and 2.3-13.6 for fenvalerate and 3.6-16.0 for cypermethrin in Shangjie populations from May 2002 to July 2004 based on LC50 at 24 hours. The resistance levels were high in spring and autumn and decreased sharply in summer. In addition, significant recovery from the knocked-down caused by the insecticides was found in the F0 and field populations of C. plutellae which were resistant to fenvalerate and cypermethrin if the parasitoids were left in contact with the pyrethroids for 1 hour. However, no recovery was found in susceptible F11 progeny.