Last Minute Mosquito Control

Q. Dear Mike—I listen to your show, so I know to clean our gutters every Spring to prevent mosquitoes from breeding up there in secret, use BTI granules and dunks to prevent breeding in ponds and wet areas around the house—and we have a propane powered Mosquito Magnet machine and garlic repellant sprays (details on these products/tactics are at the bottom of the page) to use if they show up anyway, which they don't, because, as you have explained, eliminating their breeding sites near the home pretty much eliminates the need for any follow up.

Well, we just arrived for our vacation week at a beach house on the coast of Virginia we scrimp and save all year to afford, and the sliding glass doors that lead to the deck overlooking the ocean are covered with thousands of mosquitoes!

We've been coming to this little island-like area for over 20 years and this has never happened before; the ocean breeze always kept them away. But this house has big overhangs over the deck; they keep the morning sun from pounding on the glass doors, but also create nice, still areas for the pests to rest. I used to pack a mosquito repelling garlic spray in case something like this ever happened, but it never did, so I left it home!

We can drive to a shopping center, but the locals think I'll have a better chance finding DDT down here than a natural product. What can I do that will allow us to use these doors without turning the house into a blood donation center?

---Mike, on the road in Southern Virginia

A. Yes, folks, I am indeed writing to myself—because this JUST happened to us exactly as described, and I wanted to share my solution with you.

All of these beach houses have outdoor hoses to wash the sand off your feet before you come in, and so my first thought was to hose the skeeters off the doors. But I doubted I would drown many of them, and spraying water would only make the long-term problem worse.

I had heard that some places like Home Depot and Wal-Mart were now carrying mosquito repellant garlic sprays (see below for details on these products), and although I hated the idea of wasting half a day searching through Big Box Stores, it would be better than being trapped, bitten or turning to toxins. But after a 300-mile drive, the only thing I was up for that first day was a quick two-mile trip down to the little market to get a paper and some ice cream.

Still, I walked down their bug spray aisle, where I found, as expected, chemical foggers and a bunch of DEET based mosquito repellants. Hmmm, I thought—what if I sprayed DEET on the house instead of on us? I hated the thought of buying it, but it might be a last-ditch trick to keep in mind.

Then I saw a green spray can: "Earth Options Flying Insect Killer". The active ingredient was "Eugenol", a fancy way of saying clove oil. Clove is used in a lot of natural herbicides; I guess it kills bugs too. The inert ingredients were identified as "petroleum distillates"; not my first choice, but probably not a whole lot worse than the petroleum based dormant oil sprays organic growers use on their fruit trees over winter. And a whole lot better than a regular old nerve toxin chemical fogger.

So I bought a can, used the steps up from the beach to sneak up on them and opened fire. A strong smell of cloves hit the air as thousands of mosquitoes hit the deck—so thick I had to sweep them off! I had hoped that the clove would repel them, but the oil—like dormant oil—was killing every pest it hit. The next day, I used the rest of the can, and that was it. The clove was an effective repellant, lasting until mid-week, when the wind and salt spray—we were 100 feet from the ocean—finally scrubbed it off.

So I bought a second can and that was all we needed for the week. Total investment $9. Mosquito bites, time wasted and toxins sprayed: 0. Now, if I hadn't lucked out, I would have driven around looking for garlic, which I would have preferred. But this worked fine, wasn't a poison and was a nice reassurance that non-toxic alternatives are available.

Q. We live on a sub-tropical island off the coast of Georgia. I am in search of a chemical free spray to prevent large and small insects from entering our home. Thanks,

---Karen; Saint Simons Island, GA

A. Ha! This email was waiting for me when I got home. The first answer, obviously, is to make sure your window screens are in excellent condition and that any cracks in the foundation, spaces around water pipes and such are well sealed.

Then I'd keep one of those propane-powered Mosquito Magnet machines running outside the house to trap the numerous flying, biting blood suckers you have to deal with, and spray a garlic based mosquito repellant around your doorways and the base of your house every month or so to keep out creepy crawlers.

Now let's be honest: You're always going to have a lot of life to deal with in a location like that—it's the price you pay for what otherwise is paradise. But this should cut the problem way down. Oh, and don't harm any spiders you see—they're better exterminators than any spray could ever hope to be!

Garlic sprays: "Mosquito Barrier" and "Garlic Barrier" are two of the best known; you mix them with water and apply using any standard sprayer. "Mosquito Repellent" from St Gabriel Laboratories is a pre-mixed 16% formula in a quart-sized spray bottle you hook up to a garden hose to treat 5,000 square feet of outdoor area. You'll find all three products (and other, similar ones) at some retail outlets; and on the web, of course—just search the names.

Mosquito Magnets: You've probably already seen one of these things; they mimic human scent with a chemical attractant called octenol and by using a gas-grill sized propane tank to create carbon dioxide; then the machines trap the attracted skeeters (and other blood-sucking flying fiends) by sucking them into a net. The 'Defender' (the cheapest model at around $300; protects half an acre) and 'Liberty' (around $500; ¾ acre.) both require electricity. The Pro size (over $1000; but it protects a full acre) is self-powered; no cord. The machines are widely available, both retail and mail-order.

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