【摘要】 【目的】昆虫病原线虫受到化学农药作用后,其对害虫的杀虫效果和搜寻效应可能会发生变化。本研究旨在探讨噻虫嗪处理的昆虫病原线虫对韭菜迟眼蕈蚊Bradysia odoriphaga幼虫（韭蛆）的杀虫效果及搜寻效应的影响。【方法】采用培养皿滤纸法,通过功能反应试验测定了噻虫嗪（15 mg/L）处理的芫菁夜蛾斯氏线虫Steinernema feltiae SF-SN （Sf）对韭蛆3龄幼虫的致死率和搜寻效应,比较噻虫嗪处理的Sf和未处理的Sf致死功能反应和搜寻效应的差异。【结果】噻虫嗪处理的Sf引起的韭蛆3龄幼虫的校正死亡率高于未处理的Sf引起的校正死亡率,处理6 h时,较未处理的Sf引起的校正死亡率提高了2.13倍。当Sf浓度固定在6 400 IJs/皿时,噻虫嗪处理的和未处理的Sf对该试虫功能反应均拟合HollingⅡ和Ⅲ型方程,与未处理的Sf相比,噻虫嗪处理的Sf对该试虫的攻击率（a′=0.5592）提高了42.46%,线虫寻找、寄生及致死该试虫所花费的总时间即处理时间（T_h=0.0081 d）则降低了44.90%,消耗率（a′/T_h）提高了2.59倍,日最大致死量(Na_max)则分别提高了1.81倍（HollingⅡ）和1.41倍（HollingШ）。而噻虫嗪处理的和未处理的Sf对该试虫的搜寻效应均随韭蛆密度的增加而呈线性下降。当韭蛆密度固定在40头/皿时,噻虫嗪处理的和未处理的Sf对该试虫的致死效果均随着韭蛆密度的增加而增大,搜寻效应则均先上升后下降,且噻虫嗪处理的Sf的寻找参数和相互干扰参数均高于未处理Sf的。【结论】噻虫嗪处理的Sf对韭蛆3龄幼虫的校正死亡率、瞬时攻击率、消耗率、日最大致死量和搜寻效应均高于未处理Sf的,而处理时间则显著降低。更多还原

【Abstract】 【Aim】 After the entomopathogenic nematodes（EPN） are exposed to chemical pesticides, their potential bioefficacy and searching effect on insect pests might change. This study aims to investigate the bioefficacy and searching effect of entomopathogenic nematodes treated with thiamethoxam on Bradysia odoriphaga larvae. 【Methods】 The lethal and searching effects of S. feltiae SF-SN strain（Sf） treated with thiamethoxam（15 mg/L） on the 3 rd instar larvae of B. odoriphaga were tested under laboratory conditions using a filter-paper culture method, and the differences in the functional responses and searching effect between the thiamethoxam-treated Sf and the untreated Sf were evaluated. 【Results】 The corrected mortality of B. odoriphaga larvae exposed to thiamethoxam-treated Sf was significantly higher than that exposed to the untreated Sf, and was increased by 2.13 times as compared with that exposed to the untreated Sf at 6 h post treatment. When the concentration of Sf was 6 400 IJs/petri dish, the functional responses for killing action of untreated and thiamethoxam-treated Sf on the 3 rd instar larvae of B. odoriphaga could be described by Holling’s type II and Ⅲ disc equation. The attack rate（a′=0.5592） of thiamethoxam-treated Sf increased by 42.76%, the handling time（T_h=0.0081 d）（the cumulative time taken in searching, parasitizing and killing the host） decreased by 44.90%, the consumption rate（a′/T_h） increased by 2.59 times, and the daily maximum lethal amount(Na_max) increased by 1.81（Holling’s type II） and 1.41（Holling’s type III） times, respectively, as compared with those of the untreated Sf. The searching effect of both untreated and thiamethoxam-treated Sf decreased with increasing larval density of B. odoriphaga. When the larval density of B. odoriphaga was 40 per petri dish, the lethal effect of thiamethoxam-treated and untreated Sf increased with increasing Sf concentrations, while the searching effect first increased and then decreased. The searching parameter and mutual interference parameter of thiamethoxam-treated Sf were higher than those of the untreated Sf. 【Conclusion】 The corrected mortality of B. odoriphaga larvae and the attack rate, consumption rate, daily maximum lethal amount and searching effect of thiamethoxam-treated Sf on B. odoriphaga larvae are higher than those of the untreated Sf, while the handling time is shorter than that of the untreated Sf.更多还原