You’ve perfected the bark on your pork shoulder, made sure there are vegetarian alternatives people will actually want to eat, iced down the hard and soft lemonades, laid out the fancy “unfancy” tablecloth and utensils, and bribed the kids with promises of ice cream. Only one thing could ruin your ideal backyard barbecue this summer: the arrival of the most unwanted guests of all. (And, no, we don’t mean your racist uncles, though we certainly sympathize.)

We’re talking about mosquitoes, of course.

These airborne bloodsuckers can drive even the hardiest diners inside and ruin an al fresco event in less time than it takes you to scratch an itch. Keeping mosquitoes away is of prime importance to any barbecue, but sometimes the cure can seem worse than the disease, and sprays and other remedies either don’t work or are worse than the bites. 

But let’s not understate the danger of mosquitoes, which have killed more humans throughout history than any other animal, including other human beings. As disease carriers, mosquitoes are responsible for 700,000 deaths every year, according to the World Health Organization, as humans fall victim to female mosquitoes’ insatiable quest for blood, a critical ingredient in the production of their eggs.

We asked Dr. Eva Buckner, assistant professor and extension medical entomologist at the University of Florida, and an expert on mosquito control, about the most effective and safe ways to keep your backyard ‘cue skeeter-free without your guests tasting chemicals instead of umami.

What You Shouldn’t Use to Keep Mosquitoes Away

Natural Repellents

There are many popular mosquito repellents out there that are labeled “natural,” like citronella and neem oil, but their effectiveness and safety is questionable.

“‘I always like to remind people that ‘natural’ does not always mean ‘safe,’” says Buckner. “I only recommend repellents that contain an active ingredient recommended by the CDC and have been registered by the EPA for use as repellents applied to skin.” 

Consumer Reports found natural repellents to be hit or miss in effectiveness and warned that botanicals had high concentrations of allergens, quickly wore out, and potentially left you vulnerable to tick- and mosquito-borne disease. Wirecutter, meanwhile, called essential oils “terrible” as bug repellents and sounded a warning about how unregulated the industry is. 

Foggers and Sprays

The same warning goes for chemical insecticides like sprays and those intended to coat vegetation. They definitely work to kill mosquitoes but also have the tendency to kill everything else, including helpful insects and bugs we actually enjoy having around.

“Insecticide foggers or broadcast sprayers … usually contain pesticides known as pyrethroids or organophosphates, which will kill just about any insect they come in contact with, including pollinators like butterflies and honeybees,” says Buckner. 

Mosquito Coils

Mosquito coils work, but they also stink, which makes them less than ideal for a food-based event. What’s worse is that research has shown that the smoke from mosquito coils may increase your chances of getting lung cancer.

“Coils containing allethrin, metofluthrin, and transfluthrin have been shown to be effective in repelling mosquitoes,” says Buckner. “However, concerns have been raised about potential negative impacts of breathing the smoke from burning the coils.”

Light-Based Mosquito Traps

You’ve probably seen “bug zappers” at some point, those cylindrical or pagoda-shaped gadgets that use ultraviolet lights to attract flying insects and then electrocute them. But they don’t take down enough mosquitoes to make a difference, and they involve a lot of collateral damage.

“Light-based mosquito traps will attract and trap mosquitoes, but they are unlikely to attract and trap enough mosquitoes to lead to a noticeable decrease in mosquito numbers,” says Buckner. “Many insects in addition to mosquitoes like moths and beetles are attracted to light sources used in light-based mosquito traps. As a result, many insects other than mosquitoes are killed by light-based mosquito traps.”

What Does Work for Keeping Mosquitos Away

Source Reduction

Arguably the most effective thing you can do to stave off mosquitoes also takes the most time and maintenance. If you’ve scheduled your barbecue far enough in advance, you’ll have enough time to canvas your backyard and remove and treat the places where mosquitoes love to lay their eggs: standing bodies of water, no matter how small.

“Mosquito eggs need water to hatch, and immature mosquitoes are aquatic,” says Buckner. “It’s far easier to kill mosquitoes when they are immature instead of when they are adults.”

The best course of action is to dump out water from containers like pet dishes, toys, buckets, flower pot saucers, and so on, and keep doing so at least weekly. For the water-holding objects you can’t really drain, like bird baths and plants such as bromeliads that trap water, you can use widely available pellets containing larvae-killing bacteria that doesn’t make the water unsafe for animals to drink.

Fans

Mosquitoes are weak flyers, and they find human targets by following the trails of carbon dioxide we breathe out. When fans are set at a high enough speed, they not only make it harder for mosquitoes to fly toward you, they also disperse the carbon dioxide that the pests are using as a roadmap to your bloodstream.

Topical Repellents Containing DEET or Other CDC-Approved Ingredients

Naturally, topical repellents only work for the people using them, and you don’t want to get to the point where you’re rubbing bug spray on people before you hand them a bowl of potato salad. But topical repellents containing CDC-approved active ingredients like DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol, and 2-undecanone are effective. Studies have also shown that mosquitoes seem to be more attracted to darker and brighter colors, so you can also cover untreated parts of the body with loose, preferably light-covered clothing (Mosquitoes can bite through skin-tight clothes).

Spatial Repellent Devices Using Metofluthrin or Transfluthrin

In the last few years, mosquito haters have rejoiced at the introduction of products from Thermacell that send a hemispherical dome of protection up to 20 feet in diameter. These devices spray an invisible, odorless, ungreasy mist of mosquito-repelling chemicals that are safe for humans. Even better? They shouldn’t affect the taste of your chow. 

“Spatial repellent devices containing allethrin, metofluthrin, or transfluthrin, like Thermacell products, are effective at repelling mosquitoes within a certain area surrounding the device during calm weather conditions,” says Buckner, but the downside is that wind can blow the zone of protection away.” Spatial repellents are most effective in situations when you’re not going to move a lot and there is little wind. If it is windy, the protective bubble will not be able to stay in place around you. And if you are constantly in motion, the protective bubble will not be able to keep up with you.”

Bottom Line: So What’s the Best Mosquito Repellent for Barbecues?

Ultimately, the best mosquito repellent depends on the specific circumstances you’re preparing for, so you’ll need to assess and then reassess what you need based on what happens, like if the wind blows harder or dies down between the fruit salad and the hot dogs and the dessert.

“There is no single mosquito repellent device or product that is going to work in all situations,” says Buckner. “There is no magic bullet for controlling or repelling mosquitoes.”

That said, barbecues are stationary affairs, unless you count burger-flipping as serious movement, so generally the best mosquito repellent for grilling out is pretty clear.

“I recommend using spatial repellents containing metofluthrin or transfluthrin if you are staying in one place like while grilling or eating outside on a porch,” says Buckner. “They will not contaminate or change the flavor of your food.”

And that’s what science says are currently the best ways to keep mosquitoes from ruining your backyard barbecue. Now all we’ve got to do is figure out how to solve the problem of your racist uncles.