ABSTRACT
Objective To study the first-time killing efficacy and the chain-killing efficacy of four gel baits against Blattella germanica: 1% chlorpyrifos, 0.05% fipronil, 2.15% imidacloprid, and 0.5% dinotefuran and provide a basis for drug selection in controlling Blattella germanica. Methods Laboratory killing efficacy test was conducted according to the national standard GB/T 13917.7-2009 and the chain-killing efficacy test was conducted for three rounds.The first round of chain efficacy test was conducted by feeding the cockroaches killed in the laboratory efficacy test, and each next round by feeding the cockroaches killed in the last round.Median lethal time (LT50), 95% confidence limit, and toxicological regression equation of each test were calculated by software DPS V9.01. Results The LT50 of the efficacy test with 1% chlorpyrifos gel bait was 0.745 5 (0.603 4-0.890 3) d.The LT50 of the first, second and third chain experiments increased by 3.30, 2.18 and 2.76 times, respectively.The LT50 of the efficacy test with 0.05% fipronil gel bait was 0.846 5(0.464 7-1.228 0)d, and increased by 5.42, 2.09 and 1.48 times, respectively, in the first, second and third chain experiments.The LT50 of the efficacy test with 2.15% imidacloprid gel bait was 3.192 1(2.865 0-3.506 0)d, and increased by 1.13, 1.65 and 1.15 times, respectively in the first, second and third chain experiments.The LT50 of the efficacy test with 0.5% dinotefuran gel bait was 0.997 1(0.805 8-1.191 6) d, and increased by 3.85, 1.37 and 1.78 times, respectively in the first, second and third chain experiments. Conclusion In the laboratory killing efficacy test, 1% chlorpyrifos, 0.05% fipronil, and 0.5% dinotefuran gel baits are better than 2.15% imidacloprid gel bait.In the chain-killing efficacy test, 2.15% imidacloprid and 0.5% dinotefuran gel baits are better than 1% chlorpyrifos and 0.05% fipronil gel baits.Based on our results, we recommend the use of 0.5% dinotefuran gel bait for comprehensive and sustained killing effect.
ABSTRACT
[ Objective ] To assess the resistance risk of Culex pipiens pallens to pyriproxyfen in Culexpipiens pallens, to predict the rate of resistance development and to provide the reference for scientific and rational application of insecticides. [ Methods ] The resistance strain was developed by group selection, and the realized heritability ( h2 ) of Culex pipiens pallens resistance to deltamethrin was estimated by Tabashnik's method. [ Results] The resistance of Culex pipiens pallens to pyriproxyfen had increased by 5.69-fold after 12 generations of indoor breeding, and the h2 of Culex pipiens pallens to pyriproxyfen was 0.02, indicating that a relatively risk of resistance development. [ Conclusion] The results indicate that Culex pipiens pallens has resistance risk to pyriproxyfen, so the application of the insecticide must be scientific and rational.