The Dirt: Mosquitoes!

When people call me for help in their backyard, they often ask if they have enough sun to grow a lawn, tomatoes or a plum tree, and where would be the best placement for a grill, patio or ping pong table.  Each person has his or her own list, often borne out of a desire to re-create a particularly fond memory of a garden or a lovely smell, taste or feeling. I must disagree with Tolstoy, who famously wrote that “Happy families are all alike; every unhappy family is unhappy in its own way.”  It is exactly the reverse in Brooklyn backyards.  Happiness is linked to unique, personal memories; unhappiness is all about the mosquitoes.

If you feel the mosquitoes have gotten worse, faster and more clever, you are right.  The old native house mosquitoes (dark, slow, loud) have been supplanted by zebra mosquitoes (also called tiger, Asian or forest mosquitoes.)  These newcomers are stealthier and much harder to control.  The city still calls on everyone not to leave standing water, and while that is excellent advice for swamp mosquitoes, it doesn’t really slow down zebra mosquito reproduction, as the females lay eggs in any damp environment, such as as shady, moist underbrush, not just in standing water.

Another notable difference is that female zebra mosquitoes don’t try to make one blood meal before laying eggs; instead, they make multiple small snacks.  So you may have six bites from one mosquito; worse, that mosquito might have taken blood from a bird, your dog, your neighbor’s cat and then you in short order, which explains why they are excellent vectors for contagious diseases for humans and animals.  Finally, zebra mosquitoes are active during the day.  They detect mammals through their breath and scent.

I am not telling you all this to ruin your 4th of July plans, but because knowing your enemy, you can attempt to defeat it.

1. Controlling standing water is not nearly enough.  You also must clear any permanent damp spot; any area that will remain moist for three days or more can support mosquito breeding.
2. I am of two minds about the CO2 traps.  On the one hand, watching the crunchy, desiccated mosquito bodies in the bottom drawer is quite satisfying.  On the other hand, in spite of emptying hundreds of dead mosquitoes over the summer, I couldn’t really say whether there were fewer mosquitoes altogether.  I certainly feel I got stung just as much. In addition, they are quite expensive to buy and to run; only do it if you are the sort of person who feels revenge is a soothing balm.
3. The sprays do work.  Not completely, because you will forget to spray the back of your neck or  that place right above the back of your knees.  I do like to switch to a peppermint castile soap in the summer; it does seem to make other people more appetizing to the mosquitoes if you carry a lingering peppermint oil scent.  It won’t work as well if your significant other or your friends also switch to peppermint soap.  Don’t let them read this column!
4. Xeriscape landscaping evokes images of lunar-like gravel and cacti yards, but it doesn’t have to be that way.  There are many plants that require minimal to no watering and yet are lush and colorful. Natives are a good source of well-adapted plants, but aromatic herbs (thyme, rosemary, lavenders, etc.)  and easy perennials like echinaceas, sages, asters and coreopsis need very little if any supplemental watering.  In the shade, hostas, coral bells and tiarellas thrive on dry soil.  If you have plants that must be watered regularly, such as in your vegetable garden, set that timer to 5 am when you aren’t around, and let the surface dry in between waterings.
5. If you read this blog post to the end, congratulations!  This is the best advice to control zebra mosquitoes: Create a breeze. This is where the trend of privacy fences really comes to bite us; small spaces, with lots of plants requiring daily watering (aka lawns), and zero air movement under six feet are mosquito heavens.  I always try to convince people to have shadowbox or lattice fences, to let the air through, and replace their lawns with creeping thyme.  But if you can’t change the hardscaping and just love your lawn, investing in a standing fan will change your life.  You can even buy retro chrome numbers that will look lovely in a steampunk sort of way.  Position them in a corner, and make believe there is a stiff breeze in your yard.  It will disperse the CO2 you are exhaling, and the lactic and fatty acids you are exuding.  It will also make the zebra mosquitoes miserable; do you remember they are also called forest mosquitoes?  They are not great flyers, and aren’t adapted to windy conditions.

Happy barbecue season!

The Dirt is a monthly column that explores gardening in Brooklyn by Brownstoner commenter and Brooklyn garden designer Marie-Helene Attwood of  Edible Petals. Each month, she will answer any questions about Brooklyn gardening over the following weekend.

Photo by the Center for Disease Control