With my tips for your anti-mosquito wardrobe

Dear Avant Gardener, Mostly our experience [transforming our yard] has been roses, but our biggest thorn is mosquitoes. We’ve had very wet weather. Now every time we go outside about five mosquitoes land on each of us immediately. We resort to spray sometimes. What do you recommend? — E., Virginia Beach, VA

How topical! Cases of equine encephalitis in the northeast and sloth fever in Florida have been in the news. But let’s put that in perspective: The number of human infections are measured in single digits even in affected states. Even West Nile virus, the most common mosquito-borne illness in the United States, infects fewer than 60 people in any state — and zero in Virginia Beach, according to the latest CDC data. [You can look up the number of cases in your county here.]

The itch

Worldwide, mosquitoes are the world's deadliest animal, killing 700,000 people, mostly from malaria. But here, in the United States, they are mostly a nuisance, not a threat — but a really annoying nuisance. Of the more than 200 species of mosquitoes here, only 12 carry disease. Still, most people have a mild allergic reaction to mosquito bites and the resulting itch lasts a few days.

When a mosquito secretes saliva into your bloodstream, your body registers the saliva as an allergen. Your immune system then sends the chemical histamine to the area where the mosquito bit you to remove the allergen from your body. Histamine is what causes your mosquito bites to itch and swell. Most people have a mosquito bite allergy. — Cleveland Clinic​

Consulting the experts

After you and other Transform Your Yard students mentioned getting rid of mosquitoes as a goal for your yards, Pete and I visited the USDA Center for Medical, Agricultural and Veterinary Entomology in Gainesville, Florida, which studies how to protect the US troops worldwide from serious mosquito-borne illnesses. Mosquito and Fly Research Entomologist Dan Kline gave us a tour, which included viewing mosquitoes and their larvae under a microscope. The pesky insects are surprisingly beautiful.

Mosquitoes are pollinators! (Who knew?)

Although the tour was fascinating, I was so disappointed by what I learned at the lab that it has taken me months to write about this important topic. I had been hoping for a planting solution, like the research-based anti-tick border that has been so effective at Zoe’s. Unfortunately, one of the things I learned at the lab was that mosquitoes eat nectar, not just blood; they are attracted to flowers.

Entomologists at the CMAVE and elsewhere are studying the repellent properties of essential oils, but such plant research is in early stages. I have not found reliable studies on plants that deter mosquitoes. A major challenge is that what repels one mosquito species may actually attract another. For example, according to Kline, linalool repels most species, but attracts “vicious biting” Asian tiger mosquitoes.

Planting-based solutions aside, there are still many research-based ways to decrease your exposure to mosquitoes in your yard. I’ll get to them in a moment. But first, here’s one solution to avoid if you love wildlife:

Don’t spray your yard, please

When you say you resort to spraying, are you talking about your yard or your skin? Please don’t spray your yard. I learned at the lab that the barrier sprays used by pesticide companies, as opposed to municipalities, have a residual effect that kills beneficial insects as well as mosquitoes — and may endanger you and your pets. According to the National Wildlife Federation,

Most residential mosquito control companies use insecticides known as pyrethrins, which are chemicals derived from chrysanthemum flowers that are toxic to insects; or more frequently, pyrethroids, which are synthetic chemicals that mimic pyrethrins. Whether natural or synthetic, these are broad-spectrum insecticides that are highly toxic to a wide variety of insects, not just mosquitoes.
​
We know the specific pyrethroids that these companies use such as bifenthrin, deltamethrin, and permethrin are all highly toxic to bees, killing them on contact and for one or more days after treatment, a fact the EPA itself acknowledges.
​
Mosquito sprays aren’t just toxic to insects, either. Runoff can wash these chemicals from our yards into surface waters, where they can poison aquatic organisms such as fish and crustaceans, which are highly sensitive to pyrethroids. Pets exposed to pyrethroids can experience vomiting, diarrhea, lethargy, and other symptoms. — National Wildlife Federation​

In contrast, according to Kline, public works departments like your local Virginia Beach Mosquito Control Bureau are more likely to spray at dusk when other types of insects are less active and an ultra low dose of an insecticide that kills mosquitoes in flight and not when it settles.

Based on what I learned from the mosquito lab and research studies, here are my top recommendations to avoid getting bitten in your backyard, ranked roughly from easiest to most difficult and costly. Most likely, you’ll want to implement a combination to maximize enjoyment of your yard.

1. Get outside while the sun shines.

Mosquitoes are most active at dawn and at dusk, which is about an hour before sunset. In Virginia, sunset is around 8:30 p.m. in July, so you’ll minimize mosquito exposure by getting in your playtime and cookout before 7:30 p.m. You can check sunrise and sunset times by date anywhere in the United States here.​

2. Wear light-colored clothes that cover your legs, arms, and ankles.

I seldom get the opportunity to offer fashion advice in this newsletter, but it turns out my summer wardrobe is a brilliant solution to your dilemma. When I lived in the Grenadines, where mosquitoes are as big as helicopters, I adopted an evening wardrobe of white cotton or linen long pants and long-sleeved, button-up shirts. It’s a great look — as well as effective mosquito protection.

Studies confirm:

• Mosquitoes are less attracted to white than other colors of clothing.

• Their proboscises can’t penetrate tightly woven, medium-weight cloth — think twill — nor reach us through cloth that falls away from the body.

• They tend to bite more on the lower half of our bodies (itchy ankles, anyone?).

Make sure to wear socks and consider pants that taper. Coverage is more important than color, but it’s possible to find whites for men, women, and children. And, even for kids, washable whites are fairly easy to keep looking bright with a good detergent and peroxide-based whitener.

3. DO spray repellents on your exposed skin.

Keep a basket of various repellents where you can see them before you go into your yard. Favorites will vary based on personal preferences and skin chemistry, as well as on the mix of mosquito species in your yard. According to Kline, our skin emits a cocktail of 300 compounds, which vary by individual.

Personally, I use Repel Lemon Eucalyptus Insect Repellent to protect me from mosquitoes and no-seeums in our Florida yard; it earned a 90 in Consumer Reports’ tests, making it their No. 4 recommendation. Pete prefers Sawyer Products 20% Picaridin Insect Repellent, Wirecutter’s No. 1 pick.

And by all means try products with DEET, which remains the most effective mosquito repellent. Kline emphasized that DEET is a tactile repellant, not a poison. Mosquitoes don’t like the feel of DEET on their tarsi — essentially, their feet. Below a certain concentration, DEET actually attracts mosquitoes. Kline and his colleagues at the USDA, which developed DEET, recommend a 15 to 25% solution, such as Cutter Backwoods Dry Insect Repellent, Wirecutter’s No. 4 pick.

I used such a DEET formula while on Safari in Africa, where the risk of malaria and other mosquito-borne infections is higher than in the United States. Regrettably, DEET formulations smell bad, have an oily feel, and can damage some plastics and synthetic fabrics, so I tend to avoid them for everyday use. (For more safety information, read the recent New York Times article, How Harmful is DEET?)

Whichever repellent you use, spray it on your hands and then apply to your face, rather than spraying your face directly. And do not use repellents on babies under two months old, according to the EPA.

4. Get fans for seating areas.

Another easy-to-implement recommendation from the USDA mosquito lab experts is to use outdoor fans, preferably overhead. Mosquitoes are not strong flyers and a strong fan easily blows them off course. Check out this month's cordless fan recommendations from Wirecutter for ideas

5. Experiment with soaps.

Bathing with the right soap can reduce the number of mosquitoes that land on you — but other soaps may attract them. Researchers from Virginia Polytechnic and elsewhere found that arms washed with two out of four brands of soap attracted significantly more adult Aedes aegypti females compared to unwashed arms. Only arms washed with Native Coconut and Vanilla body wash attracted fewer mosquitoes than unwashed arms and the difference was statistically significant only for one volunteer.

6. Cut down that buddleia bush.

In searching for attractants to use in traps, Kline’s lab identified buddleia (aka butterfly bush) as especially attractive to mosquitoes. It’s also invasive, so I recommend any from your yard.

7. Remove or treat areas where mosquitoes breed.

Yard hygiene is often the first recommendation for protecting against mosquitoes, but it takes time and focus. You’ve probably already removed any standing water. (Tires are often mentioned; who keeps tires lying around their yard?) Here are additional steps to take to address areas where mosquitoes breed:

• Learn to identify mosquito eggs and check for them on fountains, wheelbarrows, kids’ toys and pools, furniture (including underneath), etc. Planters and, especially, the trays underneath are a common breeding place (see image); it might be worth eliminating planters.

• Put screens over drains, septic system openings, sump pumps, and water barrels.

• Keep gutters clean so water flows easily and does not remain pooled in any area.

• Change water in bird baths at least weekly.

• Put bacterial larvicide in any remaining standing water.

For more yard hygiene suggestions, see San Diego County’s Mosquito Prevention Resources.

8. Install a bat house.

Although the best reason to install a bat house is to help conserve bats — and save human lives, too (see “Why?” below), the mosquito-eating prowess of bats is an added benefit. Bats eat lots and lots of insects, mosquitoes among them. I’ve seen estimates that a bat can consume 2,000 insects in an evening. Studies have found that only a small portion of their diet is mosquitoes, but even at 2%, that’s 40 mosquitoes per bat — or 1,600 mosquitoes if you house 40 bats. To learn how to attract bats to your yard, go to Bat Conservation International; make sure to watch their super-informative video, All About Bat Houses.​

9. Add a screen house.

You can buy a portable screen house big enough to enjoy a family dinner or game night for around $150 from Walmart. The further you put the screen house from your door, the more time you’ll spend in your yard. Even in a small, urban yard, putting a shed or screen house at the far end of your yard will encourage you to observe the changing flora and fauna as you move through your garden to get there.

A portable screen house will let you test locations and uses at a relatively low cost — and I imagine your kids especially will enjoy it. After testing uses and locations, you could sell it and build a more permanent structure. Family Handyman provides detailed plans and instructions for a DIY screen house that you can build for $500 to $1,000. For more mosquito-free destination ideas, stay tuned for an upcoming newsletter answering a reader question about sheds.

10. Move to another state.

Sorry, but Virginia Beach has 207 “mosquito days” per year — defined as days with humidity of at least 42% and temperatures between 50 and 95 degrees. And the number of mosquito days in your area is increasing. In contrast, cooler, dryer Santa Fe, New Mexico, has only 49 mosquito days per year. My interior design guru Jonathan Berger, who is a mosquito magnet, tells me that’s one of the reasons he moved there. [Check the number of mosquito days in any US city in this gift article from the Washington Post.]

— The Avant Gardener

Why, How, Wow!

Why?

A study published this month demonstrates the importance of insect-eating bats — and healthy ecosystems generally — to human health. Bat populations in the United States have plummeted as a result of white-nosed syndrome, an invasive fungal disease. Eyal Frank of the University of Chicago analyzed the relationship among bat populations, pesticide use, and infant mortality. He estimates that 1,000 human infants have died as a result of increased pesticide use to compensate for bat die-off.

I find that farmers compensated for bat decline by increasing their insecticide use by 31.1%. The compensatory increase in insecticide use by farmers adversely affected health — human infant mortality increased by 7.9% in the counties that experienced bat die-offs. These findings provide empirical validation to previous theoretical predictions about how ecosystem disruptions can have meaningful social costs. — Science

How

Introducing, anti-mosquito chic: Light-colored, covered-up looks for the whole family!

Wow!

Gorgeous Native Gardens

Here’s some autumn inspiration from Virginia's Blue Ridge Mountains, designed by Luciano Giubbilei.

Five years ago, this picturesque scene was just a field, part of a working 160-acre farm in which grass-fed Piedmontese cattle roam the undulating land. … [Says Giubbilei,] ‘I had a strong feeling I wanted to make a flower garden there and for it to be an immersive experience, surrounded by plants. The prairie-style planting was inspired by the incredible setting.’ Its concept was that it should be organically managed, low maintenance and sustainable, needing little water and encouraging biodiversity, and attuned to the endemic climate and soil. — House & Garden

Encouraging Ecological News

• Although most efforts to keep food waste out of landfill fail, Massachusetts has proved they can work, thanks to investments in infrastructure and enforcement. (Science)

• The population of America’s most endangered bird, the Florida grasshopper sparrow, is rebounding. (Climate News)

• Projects to plant trees, build shade structures and reduce the amount of pavement around schools have become high-priority as schoolyards become dangerously hot. (Washington Post)