Research at NMSU looks at the effectiveness of mosquito repellents

Mosquitoes can carry many deadly diseases, including Zika, West Nile virus, and dengue fever. Last year, there were 33 cases of West Nile virus in New Mexico. At New Mexico State University, research is being conducted to gain more understanding of the insect’s life cycle in order to disrupt the disease transmission process.

Dr. Imo Hansen works in Hansen’s lab on campus as principal investigator, studying disease-carrying arthropods, which include mosquitoes.

Recently, the laboratory has been testing insecticide resistance in mosquitoes and the efficacy of various insect repellents. What they found is that insect repellent chemicals are most effective at repelling mosquitoes for hours at a time.

The Hansen Laboratory at NMSU tests the effectiveness of mosquito repellent

Dr. Hansen says that compared to a control, Deet reduced mosquito attraction by about 40%. According to Hansen, some essential oils repel mosquitoes at a similar rate, but their effectiveness is short-lived. Unlike insecticides, insect repellents provide long-term protection to the user without harming the ecosystem.

“Especially now that mosquito season is peaking, these repellents are just flying off the shelves, and some of them work better than others, so it’s really important to know which one is the best and which one is not,” Hansen said.

Dr. Hansen and his team use a wind tunnel to conduct research that helps determine the effectiveness of insect repellents.

“When you test mosquito repellent in the field, you have a problem with the wind being unpredictable, and it can change directions and drive away insect repellents. In order to address this issue, we are using a small wind tunnel facility here in order to have a constant airflow,” Hansen said. .

The wind tunnel provides a stable environment for testing insect repellents. Using a cage filled with a predetermined number of mosquitoes and a volunteer bait downwind, the team can calculate the effectiveness of any given repellent.

Dr. Hansen says that when looking for an effective repellent, you should look for one of the following active ingredients: deet, picaridin, ir3535, lemongrass oil, and eucalyptus. These insect repellents are proven to be protective for long hours. But for Dr. Hansen, the best solution to keeping mosquitoes away is to keep them out of your living space.

“Check the screens on your windows, make sure there are screens, make sure there are no holes in them, and keep them outside your home,” Hansen said.

Shot by Johnny Cocker


Dr. Imo Hansen conducts research in the NMSU wind tunnel.

The second thing is to get rid of standing water in your backyard. This is the breeding grounds for mosquitoes, and getting rid of this habitat will reduce the number of mosquitoes in your local area. Dr. Hansen says that homes with areas of standing water, such as a pond and mosquito fish, are very efficient at controlling mosquito populations, which is one of his favorite mosquito control methods.

“I have a swimming pool in my backyard and I have a whole swarm of mosquito fish there… You don’t even have to feed them, they live off insects that fall into the water, and they will take care of the mosquitoes,” Hansen said.

As for insecticides, Dr. Hansen sees them as a temporary solution. Pesticides are effective in killing mosquitoes, but they disrupt the surrounding ecosystem and can be harmful to pollinators. Furthermore, mosquitoes actually acquire resistance to insecticides over time if they are used frequently:

“It’s an effective method, but doing all of these other things — limiting breeding habitats, using fish and checking your home is probably the most effective long-term solution,” Hansen said.

According to Hansen, being prepared and protective is your best chance at preventing vector-borne diseases.