The brown bugs, each about half the size of a pencil eraser, lie in glass petri dishes - a few on their backs, legs in the air. They died within seconds of scurrying across a piece of paper containing drops of a chemical.The next step is to find out whether that same piece of paper will kill insects that crawl over it two, three or four months from now.

This lab is the front line in the federal government's chemical warfare on a scourge that has become resistant to many insecticides and is raising anxiety - and welts - in bedrooms, college dorms and hotel suites across the country: bedbugs.

Among those leading the attack is Mark F. Feldlaufer, an entomologist at the Invasive Insect Biocontrol and Behavior Laboratory on the Agriculture Department's sprawling research center in suburban Maryland. His mission is to find compounds that kill the bloodsuckers, which have made such an itch-inducing comeback in recent years that the U.S. Centers for Disease Control and Prevention and the Environmental Protection Agency issued a joint statement last month noting their "alarming resurgence."

A common household pest for centuries, bedbugs were virtually eradicated in the 1940s and '50s by the widespread use of DDT. That insecticide was banned in the 1970s, and the bugs developed resistance to chemicals that replaced it.

Unlike many other household pests - ants, termites and cockroaches - bedbugs can live for months without a meal, hidden deep in mattress seams, box springs and baseboard crevices, behind wallpaper and in clutter around beds, making it hard to spray them. And they travel easily, hitchhiking from person to person, apartment to apartment, city to city.

Getting rid of them, experts say, has become a complex political and social problem, not only because of modern concerns about pesticide use but also because of Americans' mobile lifestyle.

"People don't even have time to check their doggone phone messages," said Michael Potter, an entomologist at the University of Kentucky, much less inspect mattresses for brown specks of feces, a telltale sign of an infestation. People also have more possessions, and all that clutter makes for great places for bugs to hide.

And rightly or wrongly, it is considered imprudent to spray insecticides in areas around the bedroom, he said. That means pest control companies are often unable to get rid of all the bugs at once. Return visits increase homeowner costs, and also risk increasing the bugs' resistance to insecticides.

Funding is limited for the kind of work the USDA's Feldlaufer is doing. Research on the public health effects of the bugs has not received much support because even though their bites can provoke allergic reactions, unlike ticks and mosquitoes they are not known to spread disease.

Nontoxic measures to fight the pests include encasing mattresses and box springs and washing clothes in hot water and running them in a dryer on high heat. But mattresses and couches can't be put in a dryer, and heat-treatment technology in apartment buildings is hugely expensive, experts said.

"It's the biggest pest problem we've encountered in several generations," said Bob Rosenberg, vice president of government affairs for the National Pest Management Association.

More bedbug complaints



In Baltimore, calls about bedbugs to the city's 311 line jumped from two in December 2008, when the city began tracking them in earnest, to 92 last month.

Washington is also seeing a big increase in calls to 311 and the health department, with the number this year - 257 - on pace to more than double last year's total, officials said.

Traditionally, complaints come from multi-unit dwellings, but the past three months have seen spikes from single-family homes and visitors who stayed in District hotels, they said.

In Ohio, infestations are so severe that Gov. Ted Strickland (D) made two appeals to EPA Administrator Lisa P. Jackson.

"The bedbug problem has created a very real physical, emotional and economically devastating situation for many Ohioans," the governor wrote in a June 30 letter.

One Dayton apartment complex owner spent more than $280,000 in an attempt to destroy the pests, he noted.

Another hired an unlicensed pesticide applicator who saturated the inside of an apartment complex with a pesticide, resulting in tenants being treated at a hospital for chemical exposure.

Strickland would like Jackson to approve the use of an insecticide that is banned for residential purposes. The chemical, propoxur, is widely used to kill cockroaches and lawn pests.

Researching solutions



Although many insecticides are approved for use against bedbugs, the great majority contain pyrethroids, a class of chemicals against which the pests have developed rampant resistance, entomologist Potter said.

Potter's research has found propoxur, which belongs to a more toxic class of pesticides known as carbamates, to be effective because it does not rely on direct contact but remains potent on surfaces where bugs crawl even after it dries. The chemical had been approved for use against bedbugs since the 1960s. But manufacturers withdrew it from residential use in 2007 after the EPA found that indoor uses posed risks to children.

Pyrethroids and carbamates both disrupt bedbugs' nervous systems, but in different ways. University of Kentucky researchers have found that the bugs have developed resistance to pyrethroids in several ways, including breaking down the toxin with enzymes before it reached its targets.

An EPA official said the agency is evaluating more data to find out whether propoxur could be used in a more limited way than Ohio has requested.

The EPA, which held a bedbug summit last year, is now leading an interagency task force on the pests that includes the CDC, USDA, Department of Housing and Urban Development and the Defense Department.

Seeking a fast fix



Until a month ago, Feldlaufer and other scientists at the USDA had been focusing on synthesizing new compounds to kill bedbugs. But even if a new chemical were effective, bringing it to market would take much longer because of safety testing. A faster solution would be to look at chemicals already used to treat agricultural pests, where safety data have been established, and determine whether those could be used to control bedbugs.

Hundreds of such pesticides exist. The EPA and USDA are working together to come up with a list for testing, ranked in order of those most likely to get a green light for indoor use, officials said.

But no new chemical would be a magic bullet. To fully eradicate the pests, there needs to be a coordinated approach that includes vacuuming, decluttering and sealing cracks to remove hiding places.

To raise public awareness about the bedbug problem, Baltimore officials have conducted door-to-door campaigns in affected neighborhoods. In the District, health officials put together a five-minute video about bedbugs that airs daily on Channel 16 and is also on the city government's Web site.

Feldlaufer hopes the new urgency will help him get more insecticide-resistant bugs to test. At his Beltsville lab, his 18 mason jars hold tens of thousands of bugs that feed on expired red blood cells (from Walter Reed Army Medical Center) that he mixes with plasma. But only two jars contain the pyrethroid-resistant ones.

His personal hope is to avoid getting bitten by the bugs ever again. He has become extremely allergic to them.

When he was a graduate student, he let dozens feed on his forearm while researching bedbugs. He developed a mild rash but didn't worry much about it. Fast-forward to two years ago, when as a longtime USDA entomologist he took up bedbug research again. He received a collection of the pests from a leading expert and decided to let them feed on his arm again.

This time, his arm swelled and reddish blisters bubbled up.

"Boom - after 10 seconds, I got that reaction, even though I had not been exposed in nearly 30 years," he said.

A photo of his blistered arm is featured in a USDA poster about bedbugs on the wall outside his lab. It's a personal reminder of his professional mission.

Staff researcher Madonna Lebling contributed to this report.