A relative newcomer to the U.S., the Asian tiger mosquito is already generating more than its share of misery. If you've found yourself swatting a little more vigorously -- and perhaps a little less successfully -- as you work in your gardens this summer, your yard may be host to this annoying, skittish, and potentially dangerous pest.
The Asian tiger mosquito (ATM) is a tropical insect found primarily in Asia and West Africa. The name refers to the white stripes on its dark body, although it may also allude to its relatively tenacious and irritating biting style. The pest recently arrived in the U.S., most likely in shipments of used tires from Japan. Relatively mild winters without prolonged cold spells have allowed the insect to survive in regions where it normally wouldn't overwinter.
A few things distinguish this pest from your regular, garden-variety mosquito. First of all, it's active in midday, unlike native mosquitoes, which prefer to feed at dusk and dawn. Secondly, it's smaller and flies faster, making it harder to swat. Thirdly, in laboratory settings it has been found to be a particularly successful bearer of mosquito-borne diseases.
However, in reality the ATM hasn't lived up to the initial fears of its potential to cause widespread diseases. This may be due, in part, to the fact that it's a generalized feeder: It's as happy dining on squirrel blood as on human blood, making it less likely to cause an outbreak than a species that travels exclusively from human to human, for example. However, the insect's mixed diet does indicate that the species will likely expand its range and spread further across the country.
Individual Asian tiger mosquitoes appear to have very limited flight ranges, on the order of up to 300 yards. That means that the insect biting you probably hatched in your yard, or your neighbor's. That's good news; it means you can have an impact on the population.
The insect is known as a "container breeder," meaning it prefers to breed in small areas of standing water, as opposed to ponds, for example. Even the smallest amount of standing water -- such as that collected in a soda cap -- is a potential breeding site. And when temperatures are ideal, the mosquito can go from egg to hungry adult in a week.
So, techniques to manage the mosquito center on removing all sources of standing water. Scour your landscape for potential breeding areas -- saucers under planters, upturned trash can lids, old tires, vases, lawn decorations that could hold a bit of water. Empty all standing water and replace water in birdbaths at least twice a week.
Encourage birds and bats to take up residence in your yard by providing nesting boxes. Although these predators consume a variety of insects, they can play a small role in managing ATM populations.
Because the ATM feeds all during the day, you'll need to be prepared any time you head into the garden. Wear long sleeves and pants, if possible, and use an insect repellent on exposed skin. Make sure you have tight-fitting window screens and doors to keep pests out of your home. Citronella candles can help repel the pests in a confined outdoor seating area. Bug zappers are not effective; they generally kill few mosquitoes and many more beneficial or benign species.
The jury is still out on whether the Asian tiger mosquito will live up to its potential as an efficient carrier of disease. Scientists are guardedly optimistic that the threat is less than originally feared. However, it still makes sense to protect yourself against this pest.
Article published on June 23, 2008.