The rain is gone

now brace for the bite

July 02, 2006|By FRANK D. ROYLANCE | FRANK D. ROYLANCE,SUN REPORTER

First, it was the rain that wouldn't stop. Soon it will be the mosquitoes.

Last week's downpours and overflowing streams filled roadside ditches, woodland pools, dips in soybean fields and every bucket and discarded tire in the region.

And that has created vast new breeding opportunities for the annoying and potentially dangerous insects.

"I think we're going to have a pretty spectacular season," said Mike Raupp, an entomologist at the University of Maryland, College Park.

More mosquitoes won't just mean more bothersome bites, but also more potential cases of West Nile virus and encephalitis in people and horses, along with heartworm in dogs.

"With the deluge, there will be an awful lot of [breeding] habitat. And if the trend of thundershowers continues, and maintains these habitats, we'll see a bumper crop by the second or third week of July," Raupp said.

Cy Lesser, the chief of the Mosquito Control Section of the state Department of Agriculture, agrees. His crews are already treating all the breeding pools they can reach before the larvae mature and fly off in search of blood.

"We've been larviciding all week," he said. "Unfortunately, the scope of the area that's flooded is well beyond our means ... so we're doing the areas we think are closest to the [human] population."

Homeowners are already calling for help. But "the bulk of our complaint calls certainly are going to begin [this] week when the adult mosquitoes are on the wing and biting," Lesser said.

That's when spraying for the adults will ramp up, too - but only in communities that already participate in the state's control program. Lesser's $3 million budget has been flat for years, he said, with no money to expand.

"It's one of those years that could potentially be a budget-buster just this summer, not even worrying about next spring," he said. The state's fiscal year runs from July through June.

Mosquitoes begin their lives when a female lays tens or hundreds of eggs in stagnant water or damp soil. If it's dry, many mosquito species' eggs can remain dormant for years until the rains resume.

The eggs hatch into wriggling larvae that stay in the water but breathe through tiny snorkels that break the surface. They grow into pupae that later transform into adults.

After mating, the males buzz off harmlessly to feed on nectar and die. The females - the only ones that bite - fly in search of blood, which provides the proteins they need to produce eggs. They might lay two or more batches of eggs in their five-week lifetimes.

Some species fly less than a kilometer in search of blood, but salt marsh mosquitoes will fly up to 30 miles.

The recent rain and flooding have made breeding possible nearly anywhere. Worried callers are telling mosquito control officials that their yards - where normally a few low spots fill up after a thunderstorm - are "almost completely flooded now, and they have been since last Saturday," Lesser said.

They have good reason to worry. "It's gonna be pretty itchy around here," Raupp said.

The mosquito expert maintains a variety of containers around his home as "mosquito meters." They include old Frisbees, 5-gallon pails and wheelbarrows that allow him to monitor breeding trends.

"It was going to be a pretty dull mosquito year here about a month ago, around Memorial Day," Raupp said. At that point, weather conditions were "droughty," and his containers were dry. May had brought just 1.6 inches of rain to Baltimore, and rainfall for the year was running 5 to 7 inches below normal.

Then the rain returned, and thundershowers filled his containers. They were quickly infested with larvae as the neighborhood's adult mosquitoes leaped at the summer's first good breeding opportunity.

Their young wrigglers are now grown, and after six days of heavy rain across most of Maryland, the new generation is busy generating another, much bigger brood.

The bugs "have just been waiting for this event to happen," he said. "They'll be feeding and dumping their eggs into what is a spectacular habitat for the larvae."

Hot weather now will keep the adult females active, mating, seeking blood meals and laying their eggs. More summer thunderstorms, if they occur, will keep the breeding pools viable.

"This is exactly what these guys need to really ramp it up," Raupp said. "It ought to be spectacular."

That's what his skeeter meter says, anyway.

"My wheelbarrow was teeming with mosquito larvae, as were my Frisbees," he said. A swale in his front yard, which is dry four years out of five, now holds 5 inches of water, and "there are literally tens of thousands of larvae in that thing."

"We are rockin'," he said, enthusiastic as only an entomologist could be about it.

New England has already seen the same response to heavy rains that fell there in mid-May. Raupp visited and got a preview. "I went into the woods, and I was eaten alive," he said.

Baltimore Sun Articles
|
|
|
Please note the green-lined linked article text has been applied commercially without any involvement from our newsroom editors, reporters or any other editorial staff.