ARS | Publication request: Laboratory and field evaluation of medicinal plant extracts against filarial vector, Culex quinquefasciatus Say (Diptera: Culicidae)

Submitted to: Parasitology Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 24, 2011
Publication Date: December 7, 2011
Citation: Kovendan, K., Murugan, K., Panneerselvam, C., Kumar, M., Amerasan, D., Subramaniam, J., Vincent, S., Barnard, D.R. 2011. Laboratory and field evaluation of medicinal plant extracts against filarial vector, Culex quinquefasciatus Say (Diptera: Culicidae). Parasitology Research. 110:1435-1443.

Interpretive Summary: Lymphatic filariasis is a mosquito-borne disease that affects more than 1.2 billion people in 80 countries. The risk of infection with the parasite is highest in Africa, Asia, and Oceania. In this study, Indian and ARS scientists at the Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, FL, determined the effects of chemical extracts of the leaves and flowers of four indigenous Indian plant species as larvicides for the mosquito vector of filariasis (Culex quinquefasciatus). In laboratory tests, larvicidal effects (LD50) of the plant extracts ranged from 87 ppm to 230 ppm. In the field, extracts from 2 plant species lowered population levels of mosquito larvae in sewage water by 92-99% 72 h after treatment. The plant extracts showed measurable toxicity to mosquito larvae and may be useful in developing countries as locally-available, inexpensive, eco-friendly biopesticides for the control of filariasis transmitting mosquitoes.

Technical Abstract: In this study, chemical extracts of Jatropha curcas, Hyptis suaveolens, Abutilon indicum, and Leucas aspera were tested for toxicity to larvae of the filariasis vector Culex quinquefasciatus. Respective median lethal concentrations (LC50) for hexane, chloroform, ethyl acetate, and methanol extracts were 230 ppm, 212 ppm, 192 ppm, and 113 ppm (for J. curcas); 213 pm, 217 ppm, 167 ppm, and 87 ppm (for H. suaveolens); 204 ppm, 155 ppm, 166 ppm, and 112 ppm (for A. indicum); and 152 ppm, 118 ppm, 111 ppm, and 108 ppm (for L. aspera). Methanolic extracts were more toxic than ethyl acetate, chloroform, and hexane extracts when tested at the same concentration. Treatment of sewage water in the field with L. aspera and A. indicum extracts reduced larval populations of C. quinquefasciatus by 92-99% at 72 h posttreatment. The results show that extracts of several indigenous Indian plant species with known medicinal properties are also potentially useful as mosquitocides for use against filariasis vectors.