BY JUAN O. TAMAYO

 LA CAMPANA, Colombia -- Clinging to a steep hillside 9,000 feet high in the Andes, Mariana Almendro's tiny garden is a gorgeous blanket of red, violet and pink opium poppies. Profitable, too, producing a milky gum that brings about $115 a pound from buyers who turn it into heroin.

 A Guambiano Indian living on a reservation a half-hour drive from the nearest paved road, Almendro, 48, sees nothing wrong with her illegal crop. ``It just brings in a little money for food,'' she said.

 But U.S. and Colombian officials are sounding an alarm over a dramatic increase in the number and size of U.S.-bound shipments of heroin seized in recent months, and a possible boom in poppy cultivation.

 While Colombia grows only 2 percent of the world's opium poppies, its heroin accounts for 66 percent of all U.S. seizures and 72 percent of the total seized on the East Coast, according to the Drug Enforcement Administration.

 And with Afghanistan's Islamic Taliban rulers outlawing poppies in a country that produced 70 percent of the world's heroin last year, mostly for Asian and European consumption, Colombian traffickers may be tempted to fill the gap.

 After pumping $1.3 billion in U.S. aid into a Colombian counter-narcotics offensive largely targeted on cocaine -- the country produces 80 percent of the world's total -- U.S. officials are now paying increasing attention to a drug once considered almost outdated.

 ``We must develop a heroin strategy,'' U.S. Ambassador Anne Patterson said. ``We're seeing a dramatic increase in heroin purity and seizures.''

 Leo Arreguin, head of the DEA office in Bogotá, said that's why he is working to add 13 agents to his staff, a 10 percent increase, devoted solely to what he called "a priority for probably everyone in the United States.''

 ``Hospitals are flooded with overdoses in Miami, in Orlando, all along the East Coast, North Carolina, South Carolina, Baltimore, New York and New Jersey, everywhere, because of this,'' Arreguin said.

 Signs of growth in the heroin trade are everywhere in Colombia, racked by a bloody war in which leftist guerrillas and rightist paramilitaries finance themselves by
 protecting the illicit drug markets.

 MORE, LARGER LOADS

 Colombian police recorded seizures totaling 1,650 pounds of heroin in the first half of this year, three times the figure for the same period in 2000 and 25 percent higher than the total seized last year.

 Arrests of ``mules'' -- travelers who try to smuggle out small quantities of heroin in suitcases or swallowed capsules -- totaled 160 in the first six months of this year,
 compared to 266 in all of 2000.

 And in a nine-day period in June, Colombian troops seized shipments of 147 pounds -- a national record -- and 66 pounds, compared to average seizures of four to nine pounds in the past year, worth $25.8 million wholesale in New York.

 ``All of a sudden, in the last three to four months we started noticing large cargoes, bulk cargoes,'' Arreguin said. ``And when you're talking about heroin, the final
 destination is always the United States.''

 Less certain is whether the increased seizures are the result of expanded poppy cultivation, improved law enforcement interdiction or new smuggling methods requiring larger shipments.

 Borrowing a page from cocaine smugglers, the usually family-based gangs that run the heroin trade have recently begun pooling their shipments, so that one big score
 can make up for many little loses, Arreguin said.

 HARD TO SPOT

 Estimating the size of poppy fields is more difficult than it is for coca, the raw material for cocaine. While coca bushes are a lowland crop easily identified by satellites, poppies are smaller plants grown on the upper slopes of Andean mountains often draped in clouds.

 The anti-narcotics division of the Colombian National Police reported a drop in poppy cultivation last year, from 16,000 acres estimated for 1999 to 15,300 acres by the end of 2000.

 But one of its senior officers in the southern state of Cauca, where La Campana is located, estimated Cauca alone holds more than 18,000 acres and that neighboring Tolima state has far more. Nine other states are known to have poppy plantations, said the officer, who asked for anonymity.

 The CIA's annual survey of illicit Colombian crops reported no poppy data for 2000 because of cloud cover during its satellite passes. But its 1999 estimate of 18,500 acres was 25 percent higher than its 1998 figure.

 ``There is more out there than we can find right now,'' Patterson said.

 Colombian police crop dusters financed largely by Washington sprayed 22,900 acres of poppies with herbicides in the first half of this year, compared to 11,400 in the same period in 2000, plus 125,000 acres of coca.

 SIMPLER CROP

 Poppies are a far different crop from coca.

 While coca is usually grown in plots of three to four acres or more and requires many fertilizers, insecticides and relatively sophisticated chemistry to turn it into cocaine, poppies are grown in much smaller plots, require little care and are much easier to process into heroin.

 But for their farmers the story is the same -- crops that are illegal yet seldom punished by a largely absent government, and that can make the difference between hunger and putting meat on the table once a week.

 The police and army abandoned their bases in Silvia, the main town in the Guambiano region, following a 1999 attack by the leftist Revolutionary Armed Forces of
 Colombia, or FARC, and have not returned.

 While U.S. and Colombian officials say they are concerned mostly about ``industrial'' plantations of an acre and up, most of the plots in this region are family-owned
 gardens no bigger than an average Miami backyard.

 One acre of poppies yields about 11 pounds a year of milky gum that hardens into opium, worth about $1,250. In comparison an acre of onions brings about $30.

 ``No one is rich here. This is just to be less poor,'' said Almendro, a widow living with her three children in a one-room adobe hut up a steep and winding gorge from Silvia.

 A year-old campaign by Guambiano leaders to voluntarily eradicate poppy fields on their reservation managed to reduce the total from 1,500 acres to less than 50, said Segundo Montano, deputy governor of the council that rules the Guambianos.

 ``We don't want fumigation. We want help with alternative development projects to alleviate our poverty,'' said Cauca Gov. Floro Tunubalá, a Guambiano and Colombia's first Indian state governor.

 The U.S. Agency for International Development is negotiating several million dollars' worth of development grants for heroin-producing regions, in return for the voluntary eradication of 7,400 acres of poppies within five years.

 But FARC guerrillas have been pressing Guambiano reservation farmers to continue planting poppies, Montano said, arguing that the Colombian and U.S. governments will never meet their promises of aid for alternative crops.

 Heroin smugglers, meanwhile, have proven to be sharp businessmen, capturing the U.S. market since the mid-1990s by selling their product at wholesale prices well
 below those of Asian heroin -- $36,000 per pound compared to $114,000.

 Cheap prices and purity so high that Colombian heroin can be smoked or snorted instead of injected -- erasing the fear of the needle and AIDS -- have led to increased use in the United States.

 The number of habitual U.S. heroin users climbed from 855,000 to 977,000 between 1995 and 2000, according to data gathered by the White House's Office of National Drug Control Strategy.

 Arreguin said such figures underline the need to create the 13-member DEA heroin task force here under the joint Colombian-U.S. counter-narcotics program broadly known as Plan Colombia.

 ``This is a priority, not only for Colombia but for American consumers,'' he said. ``Heroin has become a major problem, and if we don't do something now we're going to have more and more of our young people not only addicted but dying from overdoses.''