Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Larvicidal Effect of Latex from Calotropis Gigantea (l.) W.t. Aiton Against the Mosquito, Culex Quinquefasciatus Say (diptera: Culicidae)

Khondkar Ehteshamul Kabir
Laboratory of Integrated Pest Management, Institute of Biological Sciences, University of Rajshahi

Ataur Rahman Khan
Laboratory of Integrated Pest Management, Institute of Biological Sciences, University of Rajshahi

A.S.M. Shafiqur Rahman
Department of Zoology, University of Rajshahi; Rajshahi-6205, Bangladesh

Abstract/ Executive Summary:

A perusal of the data show that the latex produced significant mortality in the mosquito larvae at different instars compared to untreated controls and was moderately toxic at high concentrations. Our findings found positively correlated to those of earlier works that investigated the effect of plant latex on some species of mosquitoes. The mortalities obtained at high concentrations suggest that the activity of the bioactive compounds in the latex was inhibited by the influence of the microenvironment. Larvicide bioassay procedures normally correlate mortality to the concentration of material present in the medium. However, the actual dosage of test materials intended for ingestion by larvae, to serve as stomach poisons, may be affected by various confounding factors such as sedimentation, more or less selective ingestion by larvae and wide variations in the larval feeding rate. Further statistical analysis of the mortality data using one-way Anova detected the significant difference between concentrations and durations (P<0.01).

Keywords: Culex quinquefasciatus, Calotropis gigantea, Latex, Larvicidal effect

Location: Laboratory of Integrated Pest Management, Institute of Biological Sciences, University of Rajshahi

Start Date:

End Date:

Program Area: Pest Management

Commodity: Insects

Objectives:

The aim of this study was to investigate the effect of latex of C. gigantea against the larvae of the mosquito, C. quinquefasciatus Say, which is the primary vector of the filarial worm, Wuchereria bancrofti, causing lymphatic filariasis and of many different arboviruses such as WNV both in the old and new world.

Methodology:

Test material: Milky latex of C. gigantea, grown in the campus of Rajshahi University, Bangladesh, was collected in early-March of 2000 with punching of the young stems using sharp pins. Before making the various concentrations of latex in ppm, the collected latex was poured into pre-weighed conical flask and weighed to obtain the wet weight of the latex. Then the latex was dried in the same flask for 24 h at 60° C, and the flasks were weighed again to obtain the dry weight of the latex. The stock solution of the semisolid latex in MeOH (w/v) was then appropriately added to the test water medium to obtain the desired concentrations for the assay. Experimental insect: All experiments and mosquito larvae, C. quinquefasciatus Say were reared in the laboratory of the Institute of Biological Sciences, University of Rajshahi, Bangladesh at ca. 27 ±1°C, 40-60% relative humidity) and a 12:12h Light: Dark (L:D) photoperiod. The larvae were fed on brewer’s yeast (Red Star®, Wisconsin, USA) at 10, 20, 40, and 80mg/ beaker for the 1st-, 2nd-, 3rd- and 4th instars respectively. Rearing water was changed daily and at each time new food was added. Relative humidity is a crucial factor affecting the life pattern of mosquitoes, such as mating and oviposition. Larval bioassay procedure: Bioassays with latex on mosquito larvae were performed using a standard protocol of World Health Organization. Twenty-five 1st-, 2nd-, 3rd- and 4th instar larvae were released into 100ml glass beakers, containing 50ml of tap water to which the required volume of the latex preparation was applied, using a glass capillary micro-pipette (WIRETROL ®II, Drummond Scientific Company, PA, USA) to obtain the desired concentrations, viz. 1000, 2000, 4000, 8000 and 16000 ppm. Statistical analysis: The mortality data were corrected by Abbott’s formula and subjected to Probit analysis according to Finney method to estimate the concentration killing 50 percent of the larvae tested (LC₅₀) and their 95 percent fiducial limits (FL₉₅). The data were further subjected to one-way ANOVA to test the significance between concentrations and time.

Source of Information: Univ. j. zool. Rajshahi. Univ. Vol. 29, 2010 pp. 77-80; ISSN 1023-6104

Article Link (Online Journal): http://journals.sfu.ca/bd/index.php/UJZRU

Funding Source:

Budget:

Total Budget (Tk.) :

Achievement/Findings:

The possible trade-off of mortality with high concentration caused by the latex requires further investigation with changing concentrations and using solvent extraction. Indigenous technology seems to be economically feasible for controlling mosquitoes in the rural regions of the South and South-East Asian countries where sophisticated and expensive methods are not available all the time.

Knowledge Management: Journal