Bug zappers, citronella candles, bats and ultrasonic devices don't work against mosquitoes. In fact, despite decades of pesticide and mosquito physiology research, nothing repels the bugs better than DEET, a chemical the US Army patented in 1946.

Mosquitoes may be a nuisance to Americans, Fradin comments, but internationally they are a menace, transmitting diseases that may kill an estimated 1 out of every 17 people. The pests are found on every continent except Antarctica, and can pass on malaria, yellow fever, dengue fever, and encephalitis. Only female mosquitoes bite because they need a blood meal to produce eggs.

Fradin found that bug zappers, used to lure and electrocute insects, are ineffective. One study conducted in homeowners' backyards showed that of the insects killed by these devices, only 0.13% were female mosquitoes. But up to 350 billion insects that benefit humans may be killed each year by the zappers. The most effective way to reduce a local population of mosquitoes is to eliminate sources of standing water, such as old discarded tires, clogged gutters, planters, bird baths, or tree stump holes.

In addition, big, sweaty men should avoid wearing fragranced products and dark clothing. All of these characteristics attract mosquitoes. Fradin also confirms what common wisdom has long held: some people are just naturally more attractive to mosquitoes than others.

Annals of Internal Medicine June 1,1998;128:931-940.

COMMENT: As mentioned in last week's newsletter, although DEET clearly works, this chemical is NOT safe. I would strongly advise against using it at all. Please review last week's newsletter for information on non chemical alternatives like Buzz Away.