ABSTRACT
@#Abstract: Objective To investigate the population densities composition and seasonal change of mosquitoes, and resistance of Culex pipiens quinquefasciatus and Aedes albopictus several commonly used insecticides in Zigong, so as to provide a theoretical basis for guiding the scientific rational selection and use of chemical insecticides, as well as the prevention and control of mosquito-borne diseases. Methods The surveillance data on mosquitoes by traps were collected from 2018 to 2020 in Zigong. The wild Culex pipiens quinquefasciatus and Aedes albopictus were collected throughout the city and reared to F1 generation in lab. The resistance of adult Culex pipiens quinquefasciatus and Aedes albopictus to these commonly insecticides was detected by contact tube method recommended. The statistical analysis on the monitoring results was used by Excel 2010. Results The annual average mosquito densities of monitoring sites were 1.11, 10.71, and 4.81 mosquitoes/(lamp·h), respectively from 2018 to 2020. The seasonal density of mosquitoes showed a single peak curve distribution throughout the year from 2018 to 2020 in Zigong, with the highest in July. There were obvious differences in mosquito density between different habitats, with the highest density of mosquitoes in barn. The 24 h mortality of Aedes albopictus and Culex pipiens quinquefasciatus to beta-cypermethrin, lambda-cyhalothrin, deltamethrin, permethrin, malathion, fenitrothion, chlorpyrifos, propoxur, and bendiocarb were 70.71% and 3.85%, 26.53% and 1.68%, 19.79% and 1.94%, 40.80% and 0.81%, 97.98% and 3.85%, 100.00% and 7.52%, 100.00% and 66.34%, 96.15% and 33.60%, 100.00% and 71.43%, respectively. The adult Aedes albopictus larvae in Zigong was sensitive to fenitrothion, chlorpyrifos, bendiocarb, showed resistance to beta-cypermethrin, lambda-cyhalothrin, deltamethrin, permethrin, and showed resistance dubiously to malathion and propoxur. The adult Culex pipiens quinquefasciatus larvae in Zigong have developed certain resistance to these commonly insecticides. Conclusion Both Culex pipiens quinquefasciatus and Aedes albopictus had high resistance to pyrethroid insecticides, which suggested that we should strengthen the patriotic hygiene campaigns, reduce pyrethroid insecticides, use alternately different types of insecticides for delay the development of resistance and better mosquito prevention and control.
ABSTRACT
Objective To evaluate the indoor effect of six human metabolic compounds for trapping adult Culex pipiens quinquefasciatus. Methods The effects of six human metabolic compounds alone (acetic acid, propionic acid, octanoic acid, lactic acid, 1-octene-3-alcohol and urea alone), liquid lactic acid, acetic acid, propionic acid, octanoic acid, lactic acid or 1-octene-3-alcohol in combination with urea at an equal mass ratio, and lactic acid-urea combinations at various mass ratios, for trapping Cx. p. quinquefasciatus were examined using the trapping method, while the dechlorinated water served as a control. Results The indoor mosquito-trapping efficacy of the six human metabolic compounds was all superior to the dechlorinated water. Acetic acid, propionic acid, octanoic acid, or 1-octene-3-alcohol combined with urea at a mass ratio of 1∶1 had a comparable mosquito-trapping efficacy with acetic acid, propionic acid, octanoic acid, or 1-octene-3-alcohol alone (all P values > 0.05). The lactic acidurea combination at a mass ratio of 1∶1 had a significantly higher mean cumulative trapping capacity [(35.60 ± 8.11) mosquitoes] than lactic acid [(20.80 ± 8.53) mosquitoes], urea [(17.00 ± 7.18) mosquitoes] or dechlorinated water alone (7.20 ± 2.68) (all P values < 0.05). In addition, the lactic acid-urea combinations at mass ratios of 1∶1, 1∶2, 1∶3, 1∶4 or 1∶5 all had significantly greater mosquito-trapping efficacies than lactic acid, urea or dechlorinated water alone (all P values < 0.05), and the optimal combination (lactic acid-urea at a 1∶4 mass ratio) had a mean cumulative trapping capacity of (56.20 ± 9.88) mosquitoes, which was significantly superior to lactic acid [(17.00 ± 3.94) mosquitoes], urea [(16.40 ± 3.78) mosquitoes] or dechlorinated water alone [(7.40 ± 3.44) mosquitoes] (all P values < 0.05). Conclusions The lactic acid-urea combination remarkably increases the indoor trapping capability of Cx. p. quinquefasciatus, and this combination has a weak smell, which is suitable to be used at home and office environments.
ABSTRACT
Objective:To observe the fumigating insecticidal activity of 5 essential oils(asteraceae oil,rutaceae oil,mentha piperita oil,carvacryl oil and citronella oil) against Culex pipiens quinquefasciatus.Methods: Fumigating insecticidal activity was investigated by airtight fumigation in conical flask.Results: After different fumigating time,5 essential oils showed different toxity against Culex pipien quinqucfasciatus.Of 5 essential oils,rutaceae oil was the most toxic, with the LC 50 values being 0.013(0.5 h),0.055(4 h) and 0.058(24 h); asteraceae oil was the lowest toxic one, with the LC 50 values being 0.948(0.5 h),0.427(4 h) and 1.711(24 h).When LC 95 values of the 5 essential oils were used to treat Culex pipiens quinquefasciatus,the shortest fumigating time appeared in carvacryl oil(6.087 min) and the longest in citrinella oil(21.143 min).Conclusion: All the 5 essential oils have considerable insecticidal effects against Culex pipiens quinquefasciatus.Rutaceae oil and carvacryl oil are better than the others,which provides basic informations for the related field experiments.