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Updated: Aug 11, 2026
Protocols for Testing the Toxicity of Novel Insecticidal Chemistries to Mosquitoes
Published on: February 13, 2019
Comparative susceptibility of larvae of three Aedes species to malathion and permethrin
J E Cilek1, G B Craig, F W Knapp
1John A. Mulrennan, Sr. Research Laboratory, Florida A&M University, Panama City 32405, USA.
Abstract:
Larvae of Aedes hendersoni, Ae. atropalpus, and 6 geographic strains of Ae. triseriatus were compared in terms of their susceptibility to malathion and permethrin. Aedes atropalpus was most tolerant to malathion, whereas Ae. triseriatus (Walton strain) was most tolerant to permethrin. Malathion LC50S for 6 geographic strains of Ae. triseriatus ranked from high to low were: Alabama (ALA) > Michigan (UNDERC) > Indiana (WAL) > Kentucky (UKEN) > Texas (SAL) > Florida (VB); similar ranking of permethrin LC50S resulted in: WAL > VB > SAL > UKEN > UNDERC > ALA. Differences in susceptibility were detected but were not considered large (i.e., over several orders of magnitude). As a result, no change in application rate of malathion or permethrin, from an operational viewpoint, would be warranted if used against these 3 mosquito species or the geographic strains of Ae. triseriatus investigated.
Insights
This study compared mosquito larvae susceptibility to malathion and permethrin. While differences were found, they were not significant enough to alter current insecticide application rates for Aedes species.
Area of Science:
- Medical Entomology
- Insecticide Resistance
- Vector Control
Background:
- Mosquitoes like Aedes hendersoni, Ae. atropalpus, and Ae. triseriatus are significant disease vectors.
- Understanding insecticide susceptibility is crucial for effective vector control strategies.
- Geographic variation in insecticide resistance within mosquito populations can impact control efficacy.
Purpose of the Study:
- To compare the susceptibility of Aedes hendersoni, Ae. atropalpus, and six geographic strains of Ae. triseriatus to malathion and permethrin.
- To determine if observed differences in susceptibility warrant changes in operational insecticide application rates.
Main Methods:
- Larval susceptibility assays were conducted using malathion and permethrin.
- Median lethal concentrations (LC50s) were determined for each mosquito species and strain.
- Statistical analysis was performed to compare susceptibility levels.
Main Results:
- Aedes atropalpus exhibited the highest tolerance to malathion.
- The Walton strain of Ae. triseriatus showed the greatest tolerance to permethrin.
- Significant differences in LC50 values were observed among strains, but not considered operationally significant.
Conclusions:
- Current application rates for malathion and permethrin are likely effective against the investigated Aedes species and strains.
- Continued monitoring of insecticide susceptibility in vector populations is recommended.
- Further research may explore the genetic basis of observed tolerance differences.
