As a pediatrician in Fort Collins, Colorado and a 4 Tesla Mosquito Magnet, I’ve wondered whether any of the botanical products out there work against the littler biters or whether I better stick with DEET despite the toxicity concerns. Also, what about all of the legends we hear about mosquitos and their hosts? Does eating bananas really attract mosquitos? Does brewer’s yeast send them away? Do they have a preferred blood group? I promised one of our families at Pediatric Associates of Northern Colorado I’d look into these questions and share what I found out with you all.

First some stuff we can be pretty sure about:
The best way to avoid mosquito bites is to be nowhere near the places they like to congregate: standing water, gardens, forests, the early evening hours at dusk.
Mosquito-proof your yard. Get rid of stagnant water and don’t over-water plants/grass.

Stay away from using strong scented products on your children as this can attract insects.
Keep your child covered if you will be in an area with a large number of insects. Netting over their carrier or stroller may work best. Keep your child in thin/breathable clothing that covers as much skin as possible.

When using insect repellent, use only enough to lightly cover exposed skin and clothing.
Do not apply repellent under clothes, over cuts/wounds or irritated skin.
When applying to younger children: first spray in your hand and then put it on your child. Do not put insect repellent on your child’s hands or face.

With that out of the way, which repellent?
When choosing a repellent you want one that works best against the Aedes mosquitoes that tend to bite during the day and that can spread Zika Virus, as well as against Culex mosquitoes, the night-time biters that can spread West Nile Virus, and deer ticks which can carry Lyme and other diseases.

First off — The Centers for Disease Control and Protection says that all of these ingredients—including DEET—are safe, even if you’re pregnant, provided you use them properly.

Picaridin
This is a synthetic repellent modeled after a compound that occurs naturally in the black pepper plant. A 20-percent picaridin product was the most effective agent in a Consumer Reports comparison study. It was the only agent to ward off both kinds of mosquitoes as well as ticks for at least eight hours.

However, the concentration matters. Another picaridin product with just 5 percent was one of the lowest scoring insect repellents. Picaridin can irritate your skin and eyes but doesn’t have the neurotoxicity of DEET, so may be safer for children. Nevertheless, you should use it with the same cautions as with DEET containing repellents.

Oil of Lemon Eucalyptus (OLE)
This is a naturally occurring compound, extracted from the gum eucalyptus tree. In the Consumer Reports testing, one product that contained 30 percent oil of lemon eucalyptus warded off mosquitoes and ticks for at least seven hours. OLE also appears to be relatively safe when used properly, though it can cause temporary eye injury, and the Food and Drug Administration recommends against using it on children under three.

DEET
Consumer Reports found that products with 15% to 30% DEET can provide long-lasting protection against mosquitoes and ticks. However, some research suggests that higher concentrations and excessive doses can pose risks, including rashes and possibly even disorientation and seizures due to neurotoxicity. For this reason, avoid repellents with more than 30% DEET, and do not use it at all on babies younger than two months.

DEET should only be applied once per day. This is the reason that it is not recommended to use DEET and sunscreen combination products as sunscreen should be applied more often. Be sure to use soap and water at the end of the day to wash off the DEET.

What agents don’t work well? All the other products with plant oils—including cedar, cinnamon, citronella, clove, geranium, lemongrass, rosemary, or peppermint—provided little protection in the Consumer Reports comparison, often failing in within a half hour, especially against Aedes mosquitoes.
What about some of those other mosquito legends?

I found this small study from the California State Science Fair in 2010 where student Tia Tang showed a 66% reduction in mosquito landings on test subjects after taking brewer’s yeast daily for five days. (http://cssf.usc.edu/History/2010/Projects/J1321.pdf)

Brewer’s yeast is high in thiamine, or Vitamin B1, which is excreted through your pores when you sweat. Though humans can’t detect it, brewer’s yeast gives off an odor that mosquitoes find offensive and they’ll usually leave you alone. Other foods that are high in thiamine include organ meats, whole grain products.

Dark colors act as an attractant for mosquitos in studies in several studies, so wearing white, yellow and pale shades of other colors may reduce the attraction of the bugs for you.

While not an issue for our kids, drinking alcohol may increase your attractiveness to mosquitoes. In several studies, mosquito landing on volunteers significantly increased after alcohol ingestion compared with before ingestion. (http://labs.russell.wisc.edu/mosquitosite/preventing-mosquito-bites/home-remedies/)

Bad news for me: Mosquitos are more attracted to blood type O and seem a less interested in type A blood. (http://www.bioone.org/doi/abs/10.1603/0022-2585-41.4.796)

The jury is still out on the bananas (http://www.mosquitoreviews.com/bananas.html).