The Bugs Are Out There Biting

For many regions, a rainy spring spawns a summer of mosquitoes

In addition to floods, mudslides and other natural havoc, this year's wet weather has had some less publicized if irritating consequences. Their ranks swollen by record springtime rains, mosquitoes are attacking in force in many parts of the country, feasting on their human prey with buzzing fury. To Gary Benzon, mosquito-control superintendent for Plymouth County, Mass., south of Boston, there is no doubt that this will be a bumper summer for the pesky insects. "In an average year we get about a thousand calls about mosquito problems between May and September. This year we have already got close to 2,000."

As entomologists acknowledge, no one can get an accurate scientific count of mosquito populations. Nor does the plague seem to be universal. In Illinois and Indiana, wasps and bees are beginning to appear in large numbers, but residents in those states, as well as in some Mid-Atlantic areas, are enjoying a summer relatively free of mosquitoes. In New England, California and sections of the South, however, heavy rains have left pools of standing water in which the larvae of mosquitoes have flourished. Entomologist Jon Turmel of the Vermont department of agriculture cites a simple personal test. He rolls up a sleeve and lets the mosquitoes bite. Usually, he gets about 20 bites a minute. This year the bite rate has zoomed to about 35 a minute.

Mosquitoes can be more than just a nuisance. While there has been no noticeable rise in mosquito-borne diseases so far, the Centers for Disease Control in Atlanta is worried about the possibility of a rash of encephalitis in the South later this summer. The last major outbreak (2,000 cases) occurred in 1975 when there were similar climatic conditions: a mild winter followed by heavy spring rains.

In some New England, Southern and California communities, planes and spray trucks are now dousing large areas with malathion (which has largely replaced banned DDT). But many scientists are skeptical about the chemical's effectiveness, just as they are about such gadgetry as electronic bug zappers. The main impact, says Entomologist John Edman of the University of Massachusetts at Amherst, is psychological: "It reassures people something is being done."

Scientists are also using other techniques. In California, larvae-eating minnows are regularly placed in mosquito-breeding ponds. In New Orleans, U.S. Agriculture Department researchers along with local experts have been releasing a large nonbiting mosquito nicknamed Big Tox (after its scientific name, Toxorhynchites ambionensis), whose larvae dine on the larvae of smaller biting mosquitoes. Scientists have also had success with bacterial warfare: applying a larvae-killing toxin from the soil bacterium Bacillus thuringiensis israelensis (which was discovered in Israel). But BTI is expensive, must be applied directly to a breeding site, and could encourage proliferation of BTi-resistant mosquitoes.

Is there then any hope of victory in the age-old battle against mosquitoes? Probably not, most scientists agree. If the biting really gets bad, the only recourse is to retreat, swatter in hand behind a fine-meshed screen door. This file is automatically generated by a robot program, so viewer discretion is required.