Key points
- Insecticide resistance occurs when insecticides become less effective at killing mosquitoes.
- Mosquito populations can develop insecticide resistance when insecticides are repeatedly used over time.
- Mosquito control programs should routinely conduct resistance and efficacy testing.
About resistance and efficacy testing
Insecticides are used to kill mosquitoes that can transmit pathogens, such as West Nile virus, dengue virus, and malaria parasites. Insecticide application methods vary based on the target mosquito species, treatment area, and logistical considerations. Common application methods include indoor residual spraying, outdoor barrier treatments, and ground-based or aerial spraying for large areas.
Insecticide resistance testing
Using the same insecticide product over time can lead to development of insecticide resistance in mosquito populations. Even when used as directed, the product will no longer work or only partially work to kill the resistant mosquito species.
Insecticide resistance testing involves testing if active ingredients are able to kill mosquitoes in a laboratory setting. To delay or prevent the development of insecticide resistance in mosquito populations, integrated mosquito management programs should routinely conduct resistance testing to inform which products they apply.
Efficacy testing
Efficacy testing involves testing if formulated products are able to kill mosquitoes in a field setting. Routine efficacy testing can also inform which products to apply.
Why testing is important
Routinely testing for insecticide resistance and efficacy is essential for maintaining effective mosquito management strategies and protecting people from mosquito-borne diseases.
- Regular resistance and efficacy testing informs integrated mosquito management (IMM) by providing baseline data to guide decisions on which insecticides to use.
- Early detection of resistance or decreased efficacy allows for implementation of timely management strategies and helps prevent widespread resistance.
- Continuous monitoring can help programs adjust their strategy based on current resistance and efficacy levels, which ensures the IMM strategy remains effective.
Testing methods
Numerous methods can be used to test for insecticide resistance and efficacy. The list of resources below is not exhaustive. CDC and partners continue to develop more resources and will expand available guidance over time.
