龄期、饲养条件和测定方法对韭菜迟眼蕈蚊药剂敏感性的影响

Effect of larval instars,rearing conditions and bioassay methods to the insecticide susceptibility of Bradysia odoriphaga

为建立针对韭菜迟眼蕈蚊Bradysia odoriphaga Yang et Zhang幼虫(韭蛆)的可靠生测方法,采用胃毒触杀联合毒力法、人工饲料混药法和浸虫法分别测定毒死蜱、噻虫胺对不同龄期韭蛆的毒力,以明确龄期、饲养温度、食料及测定方法对药剂敏感性的影响。试验结果表明,上述三种方法测得2龄幼虫对毒死蜱的敏感性分别为4龄幼虫的11.9倍、7.4倍、3.3倍;毒死蜱对取食韭菜、人工饲料、大葱韭蛆的LC50分别为圆葱的1.84倍、1.47倍、2.31倍;在15-30℃范围内,随韭蛆饲养温度升高,毒死蜱对4龄幼虫的LC50值增大;三种方法测得毒死蜱对4龄幼虫的LC50值分别为67.199 mg/L、71.123 mg/L、88.120 mg/L,噻虫胺对4龄幼虫的LC50值依次为3.584 mg/L、2.255 mg/L、4.329mg/L,胃毒触杀联合毒力法和人工饲料混药法的毒力曲线拟合度高于浸虫法。说明龄期、饲养温度、食料、测定方法均影响韭蛆对杀虫剂的敏感性。

In order to establish a simple and reliable bioassay method to Bradysia odoriphaga, this experiment evaluated the effects of test factors to the toxicity, including different larval instars, the rearing temperatures and the different rearing diets. We determined the effects to bioassay results of the insecticide susceptibility of B. odoriphaga to Chtorpyrifos and Clothianidin by stomach-contact toxicity method, artificial diet mixed with agent method and dip method. The results showed that the sensibility of second instar larvae to Chlorpyrifos were 11.9-, 7.4-and 3.3-folds respectively compared with the forth instar larvae measured by the three bioassay methods. For the test insects fed with these four different diets, LC50 of the insects fed on the chinese chive, artificial diet and welsh onion to Chlorpyrifos were 1.84-, 1.47-and 2.31-folds compared with the insects fed on onion. In the range from 15℃ to 30℃, LCs0 of forth larval instars of B. odoriphaga to Chlorpyrifos increased as the rearing temperature rose. Tested by these three methods, LCs0 of forth larval instars to Chlorpyrifos were 67. 199 mg/L, 71. 123 mg/L, 88. 120 mg/L respectively while LC5℃0 of forth larval instars to Clothianidin was 3.584 mg/L, 2. 255 mg/L, 4. 329mg/L respectively and the fitting degrees of the toxicity curve of stomach-contact toxicity method and artificial diet mixed drugs method were superior to dip method. The study showed that the test insect instars, the rearing temperatures, the different rearing diets had asignificant influence on the insecticide susceptibility of B. odoriphaga.