How to Keep Mosquitoes at Bay

Many camping and sports stores carry clothing that has been treated with permethrin, which the Centers for Disease Control and Prevention (CDC) calls “highly effective” in repelling and killing mosquitoes and ticks.

Citronella, geraniums, and lemongrass all deter mosquitoes. “They do work, but you can’t just plant one or two,” says Tim Guy, a manager at Merrifield Garden Center. Put these plants around areas of the yard where you spend the most time.

Can’t eliminate all standing water because you have a pond, fountain, or animal-feeding trough? Try these solutions:

Mosquito Dunks contain a bacterial spore that floats in the water and kills mosquito larvae.

Agnique (sold only online) is an alcohol derivative that reduces the surface tension of water, drowning larvae.

Mosquito Torpedo contains hormones that prevent the larvae from becoming adults.

“Mosquitoes are weak flyers,” says Joe Conlon, meaning that a ceiling or floor fan can be a surprisingly effective deterrent.

ThermaCELL makes lanterns and other products that use a patented system to vaporize and spread allethrin, an odorless, synthetic version of a repellent that naturally occurs in chrysanthemums. One lantern repells mosquitoes and black flies in a 15-by-15-foot area.

Among the most widely used repellents are citronella candles, made with oil from citronella plants. Conlon says the effect is weak, so you may want to use them in conjunction with something else, such as bug spray.

While not as effective as many chemical repellents, smoke—from a tiki torch, fire pit, or charcoal grill—does keep mosquitoes at bay.

Perhaps the best defense against mosquitoes is bug spray. Three types that work:

DEET is the most effective repellent—it’s in many bug sprays, such as Off! Conlon recommends spray with a concentration of 25 to 35 percent (marked on the bottle): “Any less and it won’t work well, but protection begins to level off around 35 percent.”

Conlon says that outside the United States, the most popular mosquito repellent is picaridin, a synthetic derivative of pepper plants. One advantage: It doesn’t smell as strongly as some DEET sprays.

For a more natural repellent, try a spray made with oil of lemon eucalyptus, the only plant-derived mosquito repellent recommended by the CDC.