Toxicity of 25 synthetic insecticides to the field population of Culex quinquefasciatus Say

Abstract

The Culex quinquefaciatus Say, commonly known as the southern house mosquito, is well known for biting nuisance and vectoring of some fatal diseases. Synthetic chemicals have been relied upon as the major control measure to control mosquitoes. Therefore, we have evaluated 21 insecticides belonging to different chemical classes for their toxicity to C. quinquefaciatus females. Chlorfenapyr was the most toxic adulticide among all the tested insecticides. Among pyrethroids, deltamethrin was the least toxic adulticide, and all other have same toxicity. In case of organophosphates, the chlorpyrifos was the most toxic insecticide. Neonicotinoids such as acetamiprid, nitenpyram, and clothianidin have similar toxicity based on overlapping of 95 % confidence intervals (CI) and were more toxic when compared with the imidacloprid. The spinetoram was more toxic as compared with the spinosad (based on non-overlapping 95 % Cl). In case of ketoenoles, spirotetrament was more toxic as compared with the spiromesifen. Emamectin benzoate was the most toxic insecticide when compared with fipronil and indoxacarb. We also have tested four insect growth regulators (IGRS) including lufenuron, methoxyfenozide, pyriproxyfen, and cyromazine as larvicides. The lufenuron and pyriproxyfen have similar toxicity based upon their overlapping 95 % CI and were more toxic as compared with the methoxyfenozide and cyromazine. The methoxyfenozide was the moderately toxic among all the tested IGRS, and cyromazine was the least toxic among all the tested IGRS. These results will prove helpful in effectuating an effective integrated vector management program for C. quinquefaciatus.

Development of Ecologically Acceptable Chlorpyrifos Formulation for Effective and Safe Application

“…The high percentage mortality of mosquitoes (60%) indicates that a high fraction of chlorpyrifos is released from clay and the commercial formulation and consequently their potential for leaching into the soil profile is high. These results are in accord with recent report Shah et al[53] who found that chlorpyrifos has been shown to be the most toxic insecticide against southern house mosquito (The Culex quinquefaciatus Say). In contrast, organo-clay formulations released a significantly lower fraction of chlorpyrifos and consequently a lower percentage mortality of mosquito larvae was observed.…”

Characterization of Vitellogenin and Vitellogenin Receptor of Conopomorpha sinensis Bradley and Their Responses to Sublethal Concentrations of Insecticide

“…With long residual ingestion activity on target arthropods and low toxicity to beneficial arthropods, EB is widely used for control of pest insects ( López et al, 2010 ). In previous research, EB exhibited ovicidal activity against Cydia molesta (Busck) (Lepidoptera: Tortricideae), larvicidal activity against Culex quinquefasciatus say (Diptera: Culicidae), and adulticidal activity against Cydia pomonella (L.) (lepidoptera: Tortricidae) ( Ioriatti et al, 2009 ; Wu et al, 2015 ; Shah et al, 2016 ). However, EB was reported to be a harmless insecticide for adults of Adalia bipunctata (L.) (Coleoptera: Coccinellidae), Coccinella transversalis (F.) (Coleoptera: Coccinellidae), and Macrolophus pygmaeus (Hemiptera: Miridae) ( Cole et al, 2010 ; Martinou et al, 2014 ; Depalo et al, 2017 ).…”

Evaluation of toxicity of clothianidin (neonicotinoid) and chlorfenapyr (pyrrole) insecticides and cross-resistance to other public health insecticides in Anopheles arabiensis from Ethiopia

“…A susceptibility survey of 19 pesticides tested against insectary colonies of Aedes aegypti, Culex quinquefasciatus and Anopheles quadrimaculatus indicated that chlorfenapyr was most effective against An . quadrimaculatus and least against Culex quinquefasciatus [12]; other toxicity screens have reported that chlorfenapyr can have a lethal effect against field populations of the latter species [13]. Furthermore, multiple phase II trials in Tanzania and Benin have highlighted the effectiveness of chlorfenapyr as an adjunct to pyrethroid-treated nets against Anopheles arabiensis, Anopheles gambiae sensu stricto (s.s.), and Culex quinquefasciatus [14–18] and as a candidate for IRS in Benin [8, 10].…”