If you think all those mosquitoes in your yard are flying in from some far away swamp, you may need to think again. The Asian tiger mosquito, our state’s worst mosquito species, lives and breeds in backyards, on farms, and in urban areas – and odds are it is making its home in your yard at this very moment.
Easily identified by its distinct white and black striped legs and body, the Asian tiger mosquito is one of at least 60 types of mosquito found in North Carolina. It is of particular concern because it can spread diseases to humans and animals, including West Nile Virus and Eastern Equine Encephalitis, as well as heartworms to dogs and cats. While many garden related activities create the perfect habitat for these prolific pests to multiply, there are actions you can take today that will make your yard less appealing to them.
Tip and Toss
All mosquitoes lay their eggs in or very near standing water. The larvae that hatch from these eggs are aquatic, often referred to as “wrigglers” for the way they wriggle back and forth as they move through the water. It takes wrigglers several days to mature into adult mosquitoes.
Many of our native mosquitoes reproduce in ditches, swamps, marshes, and other permanent bodies of water where their natural enemies, which include birds, frogs, dragonflies, and fish, also reside and help keep their numbers from getting out of control.
The Asian tiger mosquito is different. It prefers to breed in small pockets of water where natural enemies cannot survive. These tenacious pests can reproduce in as little as an ounce of water. They are weak flyers, generally moving less than 1000 feet from the spot where they hatched. This means if you have Asian tiger mosquitoes in your yard they came from somewhere close by, like a clogged gutter, flower pot saucer, or birdbath.
The most important thing you can do to reduce Asian mosquito populations in your yard is to eliminate breeding sites by regularly tipping out any container that holds water and tossing items that are not needed. This includes washing out birdbaths and pet saucers daily, cleaning out gutters so they do not hold water, and storing buckets and wheelbarrows under shelters where they cannot fill with water. Getting rid of old tires and other debris in your neighborhood will help reduce mosquito populations community wide.
In pools of water you cannot empty, such as rain barrels, water gardens, swimming pools and tree cavities, you can treat with mosquito dunks. These doughnut shaped wafers contain a naturally occurring bacterium known as Bacillus thuringiensis israelensis that kills mosquito larvae before they are able to mature. Mosquito dunks containing this bacterium are effective for around 30 days and are not harmful to fish, birds, mammals or other wildlife. Other species of Bacillus are used by organic gardeners to control caterpillars, Colorado potato beetles, and some plant diseases. Pest control products containing Bacillus are available from local garden centers.
Repellents and Sprays
While reducing breeding sites is the best long term control for mosquitoes, using personal repellents is the most effective thing you can do to protect yourself when mosquito populations are high. Overall, products containing the insecticide DEET have proven to be most effective, though products containing oil from the lemon eucalyptus tree have performed as well as low concentrations of DEET in university studies. In addition, The US Department of Agriculture is currently researching compounds found in the leaves of American beautyberry, Callicarpa americana, for their mosquito repelling properties (read more here: http://www.ars.usda.gov/is/AR/archive/feb06/mosquito0206.htm)
Despite popular belief, no plants have been shown to deter mosquitoes when simply grown in the garden. In addition, no studies have shown bug zappers or sonic/ultrasonic devices to have any deterrent effects on mosquitoes.
Community wide spray programs for adult mosquito control have little impact on Asian tiger mosquito populations because they do not live in the ditches and canals these programs target. In addition, Asian tiger mosquitoes are active primarily in the daytime, whereas spray programs take place in the late evening. Spraying or fogging your yard is also of little use because this only kills the adult mosquitoes who happen to be flying around at the time you spray, while also potentially killing any bees, beneficial insects, and pollinators that may be visiting your yard. Pesticide sprays do nothing to eliminate mosquito habitat, which should be the ultimate aim of any mosquito control plan.
More images and facts about Asian tiger mosquito: http://entnemdept.ufl.edu/creatures/aquatic/asian_tiger.htm
Learn more about mosquitoes and how to control them from these online resources:
- NC Cooperative Extension Mosquito Control fact sheet:https://www.ces.ncsu.edu/depts/ent/notes/Urban/mosquito.htm#breed
- NC Cooperative Extension – Information on mosquito repellents:https://www.ces.ncsu.edu/depts/ent/notes/Urban/repellents.htm
- Find out some surprising facts about natural enemies of the mosquito from this West Baton Rouge Parish Council webpage:http://www.wbrcouncil.org/CatSubCat/CatSubCatDisplay.asp?p1=136&p2=Y&p7=36&p8=565&p9=
Subscribe to the Chatham Gardener email list to receive timely updates on sustainable lawn, garden, and landscape care for the central NC Piedmont. To subscribe:
- Visit: http://go.ncsu.edu/subscribecg
- Scroll down to enter your email address in the “address” box
- Click on the subscribe button