More than eight out of every 10 cut flowers imported to the U.S. during Valentine season pass through Miami International Airport, with Colombia and Ecuador by far the largest sources of roses, chrysanthemums, gerbera daisies, Peruvian lillies and dozens of other varieties popular every Feb. 14.

Those countries are also sources for insects that could wreak havoc on American crops and gardens — and for cocaine and other drugs sold on American streets. More than 272 million individual cut flowers passed through the Miami airport between Jan. 1 and Feb. 14 last year, a number officials say is certain to be surpassed in 2011.

"Right now is our peak season," said Rolando Suliveras, port director for U.S. Customs and Border Protection at the Miami airport. "Our workload has increased tenfold."

At a chilly refrigerated warehouse Thursday, federal agents and agricultural specialists spot-checked hundreds of boxes of flowers, shaking them down for insects and using X-rays and other methods to detect illegal drugs.

Gerard Russo, who runs Customs and Border Protection's agricutural operations at the airport, say it's common for inspectors to find 90 pests a day that could be dangerous if set loose on U.S. soil. These include moths, miner flies, aphids and thrips that could thrive in the year-round warm climate of South Florida, a key source of winter vegetables ranging from tomatoes to green beans and fruit such as avocados and mangoes.

"They don't have any natural predator insects that would feed on them here," Russo said. "They also could impact the Everglades as an invasive species."

Sure enough, an inspector found a tiny fly Thursday in one box of red roses, quickly scooping it up into a vial of alcohol as a preservative. This fly, explained CBP chief agriculture specialist Michael Diblasi, could damage U.S. plants by burrowing into leaves and sucking them dry.

Usually the flowers in a particular shipment associated with a pest are quarantined and then fumigated to kill the insects. Sometimes bugs show up that haven't been seen previously in the U.S. Russo said occasionally an insect appears that has to be sent to the Smithsonian Institution in Washington for positive identification.

The flower shipments containing drugs are handled differently.

Robert Hutchinson, assistant special agent in charge of U.S. Immigration and Customs Enforcement in Miami, said if drugs are found agents usually set up a controlled delivery so they can arrest or identify people at the destination and investigate further from there.

Drug traffickers use the overwhelming wave of Valentine's Day flower shipments as cover in hopes of getting more cocaine through in the rush, he added. Usually the drugs are inserted in boxes after they leave South American flower farms, and sometimes piles of discarded stems are found at front businesses in the U.S.

"They want to try and seize the moment," said Hutchinson, who declined to get into specific numbers or cases. "We've had some very good seizures. We have more to do."