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

Susceptibility of Third Instar Larvae of Culex Quinquefasciatus Say (culicidae: Insecta) Against Some Commercial Organophosphate and Pyrethroid Insecticides

Shirin Akhter Aney
Department of Zoology, Jahangirnagar University, Savar, Dhaka-1342, Bangladesh

Saadia Ahmad*
Department of Zoology, Jahangirnagar University, Savar, Dhaka-1342, Bangladesh

Tahmina Akter
Department of Zoology, Jahangirnagar University, Savar, Dhaka-1342, Bangladesh

Md. Golam Mostafa
Department of Zoology, Jahangirnagar University, Savar, Dhaka-1342, Bangladesh

Abstract/ Executive Summary:

Eight commercial insecticides-chlorpyrifos, bifenithrin, fenitrothion, cypermethrin, deltamethrin, cyhalothrin, dimethoate and malathion under the brand name of Dursban 20 EC, Bifenithrin 20 EC, Sumithion 50 EC, Relothrin 10 EC, Marker 2.5 EC, Reeva 2.5 EC, Tafgar 40 EC and Hilthion 57 EC, respectively were tested in laboratory at room temperature to evaluate the effective level against 3rd instar larvae of Culex quinquefasciatus Say from Savar area of Dhaka. The LC50 values for chlorpyrifos, bifenithrin, fenitrothion, cypermethrin, deltamethrin, cyhalothrin, dimethoate and malathion were 0.127, 297.474, 0.308, 0.327, 0.198, 0.189, 0.054 and 0.031 ppm respectively and their corresponding LC90 values were found to be 0.984, 2582, 0.041, 3.298, 0.728, 1.705, 0.192 and 0.030 ppm respectively. The relative potency of these insecticides tested to the larvae was found in respect to their LC50 values in the order of Hilthion 57 EC (malathion)> Tafgar 40 EC (dimethoate)> Dursban 20 EC (chlorpyrifos)> Reeva 2.5 EC (cyhalothrin)> Marker 2.5 EC (deltamethrin)> Sumithion 50 EC (fenitrothion)> Relothrin 10 EC (cypermethrin)> Bifenithrin 20 EC. However, the relative potency of these insecticides tested to the larvae was found in respect to their LC90 values in the order of Hilthion 57 EC (malathion)> Sumithion 50 EC (fenitrothion)> Marker 2.5 EC (deltamethrin)> Dursban 20 EC (chlorpyrifos)> Tafgar 40 EC (dimethoate)> Reeva 2.5 EC (cyhalothrin)> Relothrin 10 EC (cypermethrin)> Bifenithrin 20 EC. Taken together, the insecticide-malathion (Hilthion 57 EC) was found to be the most effective against the third instar larvae of Cx. quinquefasciatus in Savar area.

Keywords: Insecticides third instar larvae, Susceptibility, Cx. Quinquefasciatus.

Location: Department of Zoology, Jahangirnagar University, Savar, Dhaka-1342, Bangladesh

Start Date: 00-10-2016

End Date: 00-08-2017

Program Area: Pest Management

Commodity: Insecticide

Objectives:

The present work was undertaken to screen out eight commercial insecticides to recheck their susceptibility levels against the larval populations of Cx. quinquefasciatus say in Dhaka District.

Methodology:

Mosquito Collection: In the present study 3rd instar larvae of Culex quinquefasciatus were collected from Savar area of Dhaka District. The study was conducted from October 2016 to August 2017 in the laboratory condition at the temperature of 27°C and 77% humidity. The larvae were obtained from suitable breeding places of Culex mosquitoes such as drains, ditches, derelict ponds, stagnant drains and lakes of those locations. To collect test insect, various equipment were used such as Dipper, Enamel pan, Sweeping net, Ladle spoon, Dropper, Plastic jar etc. The larvae along with the water from the source area were kept in two-litre plastic jars covered with mosquito-proof netting. The open ends of the jars were covered with mosquito netting to avoid oviposition by other mosquitoes. The collected larvae were then brought to the laboratory and poured into a clean earthen bowl or enamel plate. The larvae were washed gently with tap water to clean them from adherent substances. The larvae were supplied with yeast and kept into mosquitoes cages. Insecticides: Chlorpyrifos, Bifenithrin, Fenitrothion, Tafgar, Relothrin, Reeva, Markar, Hilthion-all these commercial insecticides were procured from local market and used to test the susceptibility level of third instar larvae of Culex quinquefasciatus. The insecticides were organophosphates (OPs) and pyrethroids (PY) in commercial formulations. Test procedure: The larvae were collected from the field and were kept in a jar with mosquito net cage at the opening so that the adults of another species of mosquitoes did not lay eggs and up to 20 3rd instar larvae were collected and kept in another plate. Then the larvae were introduced into the test dose concentration supplied with food (yeast). These dose concentrations were kept for 24 h/48 h and 72 h in secluded. Mortality counts were made after 24 hour, 48 hour and 72 hour. The results were recorded on specially designed table. Five replicates were done with each of the dose concentrations and as well five controls. When the control mortality was between 5%-20% it was corrected by Abott’s (1925) formula. Dose Preparation: Insecticides were measured by a pipette and taken into a glass beaker of 1000ml. Then serial dilutions of these formulated products were by adding water. Five to seven concentrations were used. Different test doses were prepared making reduction of stock concentrations in the order of ¼ (250 ml in 1000 ml). For each test fresh solutions of insecticides were prepared and used on the same day. During the preparation of successive dilutions active ingredient (AI) of the insecticides were taken into consideration. The doses were used in terms of ppm (parts per million). Care was taken to avoid contamination of the laboratory equipment with insecticides. Laboratory Bioassay: In all evaluations, a batch of 20 healthy, field collected 3rd instar larvae of Cx. quinquefasciatus were placed in 120 ml of disposable plastic cup containing 100 ml different concentrations of diluted insecticides with the help of dropper. The larvae were transferred carefully to avoid physical trauma. Any larva showing abnormalities e.g., a fuzzy appearance due to the presence of parasites on the body surface was discarded. For each larvicide, the larvae were exposed to serial doses from lower to higher concentrations. Some exploratory screening tests were performed to find out the range of dose concentrations and corresponding mortality rates. After the screening tests doses were prepared in such a way that, mortality in the tests were in the range from below 50% to above 50%. In each set of bioassay 5 to 7 different concentrations were used. Thus a total of 100 mosquito larvae were exposed to each dose of insecticides and five untreated controls without any insecticide were maintained during the test. Mortality counts were made 24 hours, 48 hours and 72 hours after the treatment. The larvae that did not move after probing with a glass rod were scored as dead. The moribund larvae (incapable of rising to the surface or of showing the characteristic diving reaction when the water was disturbed; they may also show discoloration, unnatural positions, tremors, incoordination or rigor) were not scored as dead. Data Analysis: The dose-response data were analyzed using a probit analysis programme (computer software) developed by the Ecological Monitoring Research Division, Environmental Monitoring Systems Laboratory, U.S. Environmental Protection Agency, Cincinnati, Ohio-45268. The title of the programme was EPA Probit Analysis Programme, Version 1.5, which was used to determine Chi-square values, Intercept values, Slope values, LC50 and LC90 values. Computer programme plotted a predicted regression line of percentage mortality against dose concentrations in ppm. Computations performed by this programme are based on Finney (1971). Graphical presentations were done using Microsoft Excel Programme 2010.

Source of Information: Jahangirnagar University J. Biol. Sci. 7(2): 21-32, 2018 (December)

Article Link (Online Journal):

Funding Source:

Budget:

Total Budget (Tk.) :

Achievement/Findings:

From this investigation, it is clear that mosquito population is going to be resistance to a number of organophosphates and pyrethroids insecticides. For this reason it greatly complicates the control operation and also increases operational cost. To prevent the growing of resistance several steps should be taken such as putting more emphasis on non-chemical control of mosquitoes using bio-control agents, environmental management, creating public awareness. Insecticides should be used as the least resort. When used, all insecticides should be used judiciously. Repeated use of same insecticide should be avoided at all cost. Rotational use of insecticide delays the development of resistance.

Knowledge Management: Journal