What to look for when using mosquito repellers

The Associated Press

When a mosquito bites you, it pierces the skin using a mouthpart called a proboscis to suck up blood.
So you might want to pause summer vacation planning and consider what to look for in repellents, which keep bugs away from you, and insecticides, which kill them.
Repellents are one line of defense against bugs, but there are others: Wear long sleeves and long pants.
Avoid going out at dusk and dawn, when some types of mosquito tend to be most active.
HOW INSECTICIDES ARE TESTED The Centers for Disease Control and Prevention operates a mosquito lab in Fort Collins, Colorado, where it evaluates insecticides, but not repellents.
Scientists typically repeat the experiments each season to document changes in how the mosquitoes respond to insecticides, CDC officials say.


Colorado’s Fort Collins. There’s an old joke that says mosquitoes are like family—annoying, but they’re your blood relatives.

In much of the United States, mosquito season is just getting started. Additionally, that implies bug bites.

Upon biting, a mosquito uses its proboscis to puncture the skin and draw blood. It injects saliva into your skin while it feeds, which may result in a reaction such as a bump and itching. However, the pests can also disseminate viruses like West Nile, Zika, and dengue as well as parasites like malaria.

Consider what to look for in repellents, which keep bugs away from you, and insecticides, which kill them, instead of scheduling your summer vacation just yet.


In order to get protection that lasts for hours, people should look for repellents that contain DEET, IR3535, picaridin, or oil of lemon eucalyptus, according to the Centers for Disease Control and Prevention. The Environmental Protection Agency has received those ingredients’ registration.

An important note regarding lemon eucalyptus oil: Although it goes by the same name, the agency does not advise using it because it has not undergone safety testing and is not listed with the EPA as an insect repellent.

Similarly, the CDC does not recommend any other untested “natural” products.


Wearing long sleeves and long pants is one method of bug protection in addition to using repellents. Steer clear of the outdoors during the dusk and dawn hours as certain mosquito species are more active during these times.

Another preventive method that is emphasized in the game that was developed online to teach kids how to avoid mosquitoes is something else that evolutionary biologist Silvie Huijben of Arizona State University says.

Because “mosquitoes need water to breed in,” it’s critical to remove any standing water, including kiddie pools or buckets of water left untouched in the yard for a week or longer, the expert advised. “Ensure that you are not harboring mosquitoes on your property and that you are not the source of the mosquito problem in your area. “.

Additionally, to keep mosquitoes and other unwanted pests away, you can treat clothing and outdoor equipment with a pesticide called permethrin.

The methods used to test insects.

Based in Fort Collins, Colorado, the Centers for Disease Control and Prevention tests insecticides but not repellents at their mosquito lab.

In order to test these products, scientists first apply a specific amount of an insecticide ingredient inside a bottle, usually holding about 25 mosquitoes. The proportion of bugs that perish within two hours is observed, and it is contrasted with the number of mosquitoes in a nearby uncoated bottle.

In the U.S., the test is widely utilized. S. Moreover, it is being utilized more frequently globally. Compared to some more involved options, such as a test where insecticide drops are directly applied to mosquitoes, it is thought to be easier to use and less expensive.

According to CDC officials, scientists usually repeat the experiments every season to record variations in the mosquitoes’ responses to insecticides.

Repeating the test, according to Huijben, is crucial because of its limitations. For example, there’s a chance that different amounts of chemical may have been applied to each bottle, which could skew the results.

Huijben, who has compared resistance testing methodologies, stated, “I think we’re seeing a lot of noise in the data,” which could result in incorrect initial conclusions.


Bugs can grow resistant to some of the chemicals designed to kill and repel them, just as bacteria can eventually learn to resist antibiotics.

This type of resistance has been demonstrated by pyrethroids, the class of insecticides that includes permethrin.

When it came time to control adult bugs, pyrethroids became a popular alternative to older pesticides in the 1990s. The chemicals are used by farmers and community mosquito-control programs, but they are also available to homeowners on hardware store shelves.

Roxanne Connelly, an insect scientist at the CDC, stated that while resistance varies in lab experiments depending on the product and dosage, in some tests “none of them (mosquitoes) will die.”.

More in-the-field testing is being conducted by CDC officials in collaboration with state and local officials. One such experiment involves checking mosquitoes kept in outdoor cages after an insecticide fogging truck passes by.


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