THE VIRGINIAN-PILOT
Copyright (c) 1996, Landmark Communications, Inc.
DATE: Sunday, September 1, 1996 TAG: 9609010068
SECTION: LOCAL PAGE: B3 EDITION: FINAL
SOURCE: BY IDA KAY JORDAN, STAFF WRITER
DATELINE: PORTSMOUTH LENGTH: 102 lines
How do you count mosquitoes?
It's easy, says Jim Rindfleisch.
A mosquito expert with York County and part-time employee of the U.S. Army, Rindfleisch said there is nothing complicated about getting the numbers on the tiny pesky insects.
``You just stand there, let them land on you and count,'' he said. ``You count for one minute and the number is the landing rate.''
That, he said, is the ``easy way to do it.''
Rindfleisch said the landing rate method does not require that the counter let the mosquitoes bite.
``You count them and brush them away,'' he said.
And a prudent counter can wear white coveralls like those worn by beekeepers.
The U.S. Army Corps of Engineers said one spraying of insecticide over the Churchland area in early August reduced the mosquito population's landing rate at Craney Island from 50-60 per minute to only three.
A second spraying last Tuesday reduced the rate from 35-40 per minute to zero on Wednesday and Thursday.
``But that doesn't mean they're all gone,'' said Craney Island manager William Rawls on Friday. ``This is not a permanent fix. It's a long process, and we'll spray again later this month.''
Rawls and Rindfleisch, a biologist, also take the mosquito census two other ways.
``We use the New Jersey Light Trap,'' Rindfleisch said. ``It's made of stainless steel and contains a fan and a light bulb. It runs all night, and the mosquitoes are attracted to it, drop into a cup they can't get out of, and we count them in the morning.''
One morning before the spraying last week, Rawls said, he collected 400 mosquitoes from his light trap. On Thursday morning, just six of the insects had fallen into the trap overnight.
The third method of counting involves finding the wet places where female mosquitoes lay their eggs, which take about 10 days to mature. Counters can determine the effectiveness of the spraying by the number of eggs being laid.
``We sample the water to see how many are in it,'' Rindfleisch said.
He said that one female mosquito from any species will produce 500-600 eggs ``if blood fed,'' so it's very important to kill the female adults.
``It's only the females who bite,'' he said. ``They need the protein from your blood to produce the coating for their eggs.''
Male mosquitoes, he said, just don't bite.
The aerial spraying of the insecticide Dibrom is done by an Air Force C-130 flying at an altitude of about 150 feet.
The highly diluted substance, about a half-ounce of Dibrom per acre, slowly drifts over the site.
Rawls said Dibrom used in such a small amount is only harmful to mosquitoes and honeybees.
``We don't have any honeybee-keepers in the buffer zone where we are spraying,'' he said. ``And it doesn't hurt butterflies or other insects.''
The insecticide is short-lived, about 30 minutes, Rawls said, and leaves no residue.
The spraying was arranged by the Corps of Engineers, which owns part of Craney Island, a fill area on the James River where dredge spoils are dumped.
In addition to the dredged material area, Craney Island also includes the Navy's Fuel Supply Depot, the Coast Guard Support Base and the city's landfill.
Nearby Churchland residents complained to the city and to the corps when they were unable to walk in their yards without being covered with mosquitoes.
While some residents have blamed the Craney Island landfill for their problems, Rawls insists that the corps is ``not the bad guy.''
``Anywhere there's water standing, you'll find mosquito larvae,'' he said. ``That's why they spray such a large buffer area.''
The plane sprays about 5,800 acres spanning the Churchland shore from West Norfolk to Hofflers Creek at the Suffolk line.
The flights over Craney Island and the lower Peninsula are made by a specially equipped C-130 from Youngstown Air Reserve Base in Ohio.
Rindfleisch has been working with mosquitoes for 17 years and with spray flights to destroy them for 12 years.
He said that 40 or more species of mosquitoes are found in this area and about 10 of them infest Craney Island.
Although complaints from Portsmouth residents about the mosquitoes have escalated in recent years, Rawls said there is nothing new about the complaints.
``In a log kept at Craney Island in the 1700s, I saw where one fellow wrote: `The mosquitoes are atrocious,' '' he said.
Salt marsh mosquitoes are the most frequently seen variety in the area.
Some of the mosquitoes, known as crepuscular, are more active around sunrise and sunset, he said, and the psorophora ciliatu is the ``really big one'' seen around Craney Island.
``But there's a new one that's a day biter too,'' Rindfleisch said. ``It's the Asian tiger, and it's just showing up here.''
Not only does the Asian tiger see fit to bite humans all day long, it also does not require the usual one-fourth of an inch of water to lay eggs, Rawls said.
``All it needs is a little moisture, and they can breed anywhere,'' he said.
``That's not good.'' ILLUSTRATION: MARK MITCHELL photos
The Virginian-Pilot
Craney Island manager William Rawls collects the contents of a
mosquito trap. At left is a sample of what was collected. ``It runs
all night, and the mosquitoes are attracted to it, drop into a cup
they can't get out of, and we count them in the morning,'' Rawls
said of the New Jersey Light Trap. by CNB