Manzoor F, Pervez M
Department of Zoology, Lahore College for Women University, Pakistan.
J Econ Entomol. 2017 Dec 5;110(6):2527-2533. doi: 10.1093/jee/tox249.
The aim of this study was to test the bioavailability and degradation in soil of the termiticides bifenthrin and fipronil, which are used to treat subterranean termites (Heterotermes indicola, Wasmann). Soil collected from different areas of Lahore was categorized as sandy clay loam (SCL) or sandy loam (SL). Laboratory bioassays were conducted to determine the bioavailability ratio of bifenthrin and fipronil in each type of soil after different periods of time. LT50 values were determined posttreatment at different time intervals. Regarding soil type, both termiticides were more effective in SL soil, compared with SCL soil posttreatment. There were significant differences in termite mortality in treated compared with untreated control samples (P < 0.005). To test the degradation rate of soil termiticides, both qualitative and quantitative analyses were carried out by HPLC, and the effect of time on termiticide recovery rate determined. Calculated half-life values for bifenthrin (maximum, 1,002 and 1,262 d in SCL soil and SL soil, respectively) indicated that it persisted in both soil types at all concentrations. The maximum calculated half-life values of fipronil were 270 and 555 d in SCL and SL soil, respectively. At lower concentrations and over longer periods of time, fipronil completely degraded in SL soil, while a negligible amount was detected in SCL soil. Termiticide concentration decreased over time, as did the termiticide recovery rate. Overall, bifenthrin was more persistent than fipronil under all treatment conditions tested.
本研究的目的是测试用于防治地下白蚁（印白蚁属，瓦斯曼）的杀虫剂联苯菊酯和氟虫腈在土壤中的生物利用度和降解情况。从拉合尔不同地区采集的土壤被分类为砂质粘壤土（SCL）或砂壤土（SL）。进行了实验室生物测定，以确定不同时间段后每种土壤中联苯菊酯和氟虫腈的生物利用度比率。在不同时间间隔处理后测定LT50值。关于土壤类型，与处理后的SCL土壤相比，两种杀虫剂在SL土壤中更有效。与未处理的对照样品相比，处理后白蚁死亡率存在显著差异（P < 0.005）。为了测试土壤杀虫剂的降解率，通过高效液相色谱法进行了定性和定量分析，并确定了时间对杀虫剂回收率的影响。计算得出的联苯菊酯半衰期值（分别在SCL土壤和SL土壤中最大为1,002天和1,262天）表明，它在两种土壤类型中的所有浓度下都能持续存在。氟虫腈在SCL和SL土壤中的最大计算半衰期值分别为270天和555天。在较低浓度和较长时间内，氟虫腈在SL土壤中完全降解，而在SCL土壤中检测到的量可忽略不计。杀虫剂浓度随时间降低，杀虫剂回收率也随时间降低。总体而言，在所有测试的处理条件下，联苯菊酯比氟虫腈更持久。
