氟铃脲对韭菜迟眼蕈蚊不同虫态的致毒特点及毒力

Toxic characters and toxicity of hexaflumuron against Bradysia odoriphaga Yang et Zhang( Diptera: Sciaridae) at different developmental stages

为明确氟铃脲对韭菜迟眼蕈蚊不同虫态的致毒特点及毒力,采用胃毒触杀联合毒力法、药液定量滴加法及药膜法分别对韭菜迟眼蕈蚊卵、幼虫、蛹、成虫进行了生物测定。结果表明,经氟铃脲处理的0.5~1、1.5~2和2.5~3日龄韭菜迟眼蕈蚊卵至孵化24 h后,LC_（50）依次为2.27、1.60和0.64 mg/L,对1.5~3日龄卵的毒力高于对0.5~1日龄卵;经氟铃脲处理的2日龄卵、2龄幼虫、4龄幼虫、1日龄和3日龄蛹至羽化时LC_（50）分别为0.06、0.30、0.34、24.05和27.42 mg/L,毒力程度随韭菜迟眼蕈蚊发育而逐步下降;对蛹和成虫毒力较低,100 mg/L氟铃脲染毒1、3日龄蛹的羽化率分别高于10%和20%;药膜法100、1 000 mg/L氟铃脲处理成虫24 h,校正死亡率低于20%。研究表明,氟铃脲对韭菜迟眼蕈蚊各虫态的生长发育均有不利影响,抑制卵的孵化并导致初孵幼虫存活率降低;对幼虫毒杀作用较慢,对蛹及成虫阶段毒力较低。

To figure out the toxic characters and toxicity of hexaflumuron against different developmental stage Bradysia odoriphaga Yang et Zhang（ Diptera： Sciaridae）, bioassays were conducted using stomach-contact combination toxicity methods,the dripping ration liquid methods and the dry film residue method under laboratory conditions to determine the toxicity against eggs,larvae,pupae and adults of B.odoriphaga,respectively. The results showed that the LC_（50） values of 0. 5- 1,1. 5- 2 and 2. 5- 3 dayold eggs treated by hexaflumuron were 2. 27,1. 60 and 0. 64 mg / L,respectively,when observed until 24 h after new larva hatching. It was more toxic to the 1. 5- 3 day-old eggs than to the 0. 5- 1 day-old eggs. The LC_（50） values of 2 day-old eggs,2nd instar larvae,4th instar larvae,1 day-old pupae and 3 dayold pupae of B. odoriphaga treated by hexaflumuron were 0. 06,0. 30,0. 34,24. 05 and 27. 42 mg / L,respectively. The toxic level decreased progressively with the developmental process of B. odoriphaga.The toxicity to pupae and adults were lower than to larvae. At the dose of 100 mg / L,the emergence rates of 1 day-and 3 day-old pupae were above 10% and 20%,respectively. Besides,the corrected mortality rate of adults treated by dry film residue method was less than 20% after 24 h at the dose of 100 and1 000 mg / L. This study indicated that hexaflumuron had negative impacts on each developmental stages of B. odoriphaga,which could inhibit the hatching rate of eggs and decrease the survival rate of newlyhatched larvae. The toxic speed of hexaflumuron against larvae was slow,and lower toxicity was shown during pupal and adult periods.