EVALUATION OF RESISTANCE IN TEN GENERATIONS OF CULEX QUINQUEFASCIATUS (SAY, 1823) EXPOSED TO METHANOLIC LEAF EXTRACT OF CALOTROPIS PROCERA

S Adamu ,G J Sow ,I S Ndams

doi:10.33003/fjs-2020-0402-214

Abstract

Mosquitoes constitute a serious Public Health menace, resulting in millions of death worldwide each year. Emergence of insecticide resistant strains of the mosquitoes poses a serious threat and hence calls for alternative control measures. This study assessed the larvicidal efficacy of the methanolic leaf extract of Calotropis procera against the 3rd instar larvae of Culex quinquefasciatus, after ten generations for 24 hours of exposure. Larvicidal activities of the leaf of the plant were studied on laboratory reared larvae of Culex quinquefasciatus at concentration ranges of 15 mg/L to 19 mg/L. The LC50 values were obtained from Probit analysis at 95% confidence limit (CL). Results of the study indicated that the LC50 values obtained from the parent generation (F0) to the tenth generation (F10) were; 15.79 mg/L, 16.58 mg/L, 17.29 mg/L, 18.07 mg/L, 18.95 mg/L, 19.99 mg/L, 20.65 mg/L, 21.18 mg/L, 22.80 mg/L, 25.16 mg/L and 32.98 mg/L respectively at 24hours. A higher efficacy of activity was exhibited by the extract at the parent generation (F0) with lowest LC50 of 15.97 mg/L at 24h. The results of this research therefore underscore the efficacy of the plant and further suggest the use of the leaf extracts of Calotropis procera in the control of mosquito vectors and indirectly to the diseases they vectored.

Highlights

Culex quinquefasciatus Say is an important vector of a wide variety of pathogens and parasites of medical and veterinary diseases worldwide and is a potential vector of the filarial worm Wuchereria bancrofti, the agent of bancroftian filariasis (Jitpakdi et al, 1998; Triteeraprapab et al, 2000; Pumidonming et al, 2005)
It helps in transmitting malaria, dengue, chikungunya, filariasis Japanese encephalitis etc. which lead to thousands of deaths yearly [World Health Organization (WHO), 1995]
We found the methanol leaf extract of this plant effective against the larvae of Culex quinquefasciatus

Summary

Introduction

Culex quinquefasciatus Say is an important vector of a wide variety of pathogens and parasites of medical and veterinary diseases worldwide and is a potential vector of the filarial worm Wuchereria bancrofti, the agent of bancroftian filariasis (Jitpakdi et al, 1998; Triteeraprapab et al, 2000; Pumidonming et al, 2005). Chemical insecticides have the advantage of speedy action and easy application Their continuous use causes the development of resistance in insects in many parts of the world such as South America, Sudan, Sri Lanka, Nigeria, Burkina Faso, Egypt, Guatemala, USA, Turkey, and Syria (Malcolm, 1988; WHO, 1992). A botanical phytochemical, with mosquitocidal potential are recognized as potent alternative insecticides to replace synthetic insecticides in mosquito control programs due to their excellent larvicidal, ovicidal, adulticidal and repellent properties (Govindarajan et al, 2008). It is not known if these vectors will develop resistance to botanicals with continual usage.

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