When Dorothy Rogers flew from London to Washington yesterday, she packed two apples and a banana for her 19-month-old son to eat on the eight-hour flight.

By the time she landed at Dulles International Airport, Rogers and her son had forgotten about the fruit.

But Lady, a 5-year-old, 16-pound beagle, who is the federal government's answer to the problem of smuggled fruits and meats, quickly reminded them.

The dog, part of an Agriculture Department pilot program to keep foreign pests and diseases out of the United States, was on display at Dulles yesterday, sniffing at luggage from London and Paris.

As reporters and Agriculture officials watched, Lacy scored several of what her handler, Mike Simon, called "good hits." The dog worked four international flights and found a variety of smuggled fruit, as well as yogurt, liver pate and sausages. All were contraband and seized by USDA inspectors as examples of what types of food cannot be brought into the country.

"Beagles have a superior sense of smell," said Simon before the arrival of Pan Am's Flight No. 99 from London and Air France Flight 015 from Paris. "Some people say it's 100 times better than a human. Some say it's 1,000. But, it's very acute. She just sticks her nose up in the air and traces a smell to its highest concentration, which is often a lady's handbag."

Inspection officials usually have to pick and choose which bag to open, a hit and miss system. Lady's nose succeeds 60 to 70 percent of the time, her handler said.

The dog is one of four beagles the Agriculture Department has in training for use at selected airports around the country. Lady is based in San Francisco.

She was trained to single out pork, beef, citrus and mangoes, but officials said her repertoire is much larger and now includes 30 varieties of fruit, including such exotics ones as rambutans, a rich red fruit from Thailand.

Having identified a suspect suitcase, Lady plants herself beside it, nose twitching. That is what she did when, while trotting beside the baggage carousel, she sniffed out the apples and the bananas in Rogers' luggage.

Yesterday Lady worked the London flight with 348 passengers, and the Paris one with 87. Because she is so small -- the smallest beagle Simon said he has ever seen -- even the most tired-looking of passengers seemed amused as she trotted by, nose in the air.

"Hey, what's she going to be when she grows up?" one man called out.

"I think it's great," said Brian Weinstein of Washington, who teaches at Howard University. "What a cute dog. And, it sure saves the customs inspectors the trouble of sniffing the bags, doesn't it?