WITH sunlight glinting off his diamond-encrusted ring, Armando Cruz Guillen points at the surrounding hills. "These avocado trees are clean," he vows. d stake my life on it."Mexico is the world's biggest avocado producer. It exports the cream-green fruit to Japan, France, Germany, Britain, and the Netherlands. But since 1914, the United States has banned the import of avocados from Mexican growers such as Mr. Cruz. The embargo is aimed at preventing certain pests only found in Mexico, such as avocado seed weevils, seed moths, and certain fruit flies, from invading and decimating California and Florida orchards. But in the heart of Mexican avocado country, the US explanation doesn't wash. "It's not the seed weevil. It's our prices. US growers are protecting their market," says Jorge Fernandez Barragan, president of Mexico's Avocado Packers and Export Association. Indeed, Mexico's chief negotiator in the free-trade talks with the US and Canada often highlights this issue as an example of an unfair trade barrier. "With a free-trade agreement, if you're going to sell here, we have the right to sell there," Mr. Fernandez says. US officials deny the ban is to keep out competitors. "This is not a political question. It's a sanitary question," says Ed Ayers of the Animal and Plant Health Inspection Service of the US Department of Agriculture. Nonetheless, sandwiched between the $250 million-a-year US avocado industry and the Bush administration's desire to smooth the way for a free-trade agreement, the USDA is under some pressure to come up with a solution. And Mexican agricultural officials must produce more than cross-my-heart vows the avocado groves are pest-free. A binational committee which met recently in El Paso, Texas, has focused on the possibility of certifying the state of Michoacan, where most avocados are grown, as pest-free. At the talks, Mexico presented the long-awaited results of a Michoacan avocado pest survey. US officials must now review the survey. "If they provide us with adequate data proving a defined area is free of pests, then we can make a decision," Mr. Ayers says. Even if the survey passes muster, Mexico may face yet another hurdle. When the state of Hawaii wanted to ship avocados to the mainland, it had to do a 10-year study to prove its pest-free status. "We're looking for a solution. But it's a formidable task," notes Dan Sheesley, a US member of the binational committee. Another option is that Mexican avocados could be shipped in sealed containers and perhaps only to markets in the Northeastern US - far from the California and Florida orchards. But the 6,200 California growers producing nearly 90 percent of the US crop aren't exactly pleased with the tide of events. "What's to keep a shipment of avocados sent to Chicago from being resold in California? There are no border inspection stations between [US] states," says Avi Crane, director of industry affairs for the California Avocado Commission. "There is no known chemical treatment for seed weevils. Once infected, the only solution is to chop the trees down, burn the area, and move on." But Marco Antonio Careon, director of sanitary regulations for the Mexican agricultural department, disagrees. "The weevil can be killed in the soil, with pesticides legally available in the US, before it attacks the trees." He says fruit attacked by the weevil has a hole in it and usually falls to the ground before maturity, and therefore is not export quality. Meanwhile, US border officials are battling smugglers. Last year 140,000 pounds of avocados were seized; many of these were infested. US officials want Mexico to crack down on smugglers before granting legal access. But Guillermo Hinzpeter, president of Aguacates del Cupatitzio, an export cooperative, says the smuggling is an indication of the unmet US demand. US growers produce 200,000 tons annually. Of Mexico's annual 600,000-ton crop, only 2 to 3 percent is exported. "We're looking for a complementary solution," Fernandez says. "We don't want to ship during their season.... But during the four months [October to January] they don't produce, we could send our fruit north." California producers say they aren't worried about competition. "We're already competing with imports from Chile and New Zealand," Mr. Crane says. "But we can't compete with pests."