House & Home

Mosquito sprays generally safe, NC State expert says

Posted May 13, 2014

— More people are turning to mosquito-spraying services to help keep the pests away as they enjoy the outdoors.

But what's in those sprays, how safe are they, and how effective are they?

Mike Waldvogel, an entomologist and associate professor at North Carolina State University, says companies generally use two kinds of solutions to treat yards. One is garlic-based, and the other common solution contains pyrethrin.

The garlic-based solution, he says, acts as a repellant rather than a mosquito-killer.

"It's like when the highway's closed and you have to detour, you still get to your destination," Waldvogel said. "Mosquitoes are going to try to do the same thing."

Pyrethrin is a derivative of chrysanthemums, and for mosquito treatment, it is generally safe for people, Waldvogel said.

"Pyrethrins are not really durable, so after about 24-plus hours, you're really not going to see much of an effect," he said. "It's something that knocks down the mosquitoes right now."

Every mosquito-spraying company uses different mixtures of pesticides, so it might vary as to how long a treatment lasts.

Waldvogel says it's also a good idea to keep flowering plants covered during a spray, because the insecticide also kills helpful insects, such as ladybugs, which feed on other plant-eating insects.

Another way to help prevent mosquitoes, he says, is to get rid of standing water around the house.


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  • bcde May 20, 2014

    The citronella plant (aka mosquito plant) also works really well. We have one on either side of our patio and they pretty much keep the mosquitos at bay all summer long.

  • Titus Pullo May 14, 2014

    When there are no more honeybees to polinate our food crops I hope that some of these people who pay for this service remember their part in the fiasco.

  • busyb97 May 14, 2014

    View quoted thread

    Thanks for the concise list and tip on the spreaders. I've seen and recently been pinning lists of these types of plants, but they don't always warn you about the spreading variety!

  • swoodley May 14, 2014

    We don't have a mosquito problem because we grow herbs and other plants outdoors that naturally repel mosquitoes without harming pollinators and other beneficial, good insects.  Plants that repel mosquitoes:   basil, rosemary, lemon balm, lemongrass, sage, lavender, lemon thyme, creeping thyme, English thyme, peppermint (keep in containers as readily spreads), lemon balm (keep in containers as spreads , though not as quickly as peppermint), bee balm (keep in pots as readily spreads), and ageratum (an ornamental, blue-flowering annual).