Barefoot and without a protective mask or gloves, Seuon Siap padded through her cauliflower patch, dousing it with a deadly cocktail of pesticides.

Her daughter sat among the sprayed, reeking leaves, and two cows munched grass along the edges of the patch. The 50-year-old farmer wasn't sure exactly how her mix of three pesticides worked because she could not read the foreign language instructions on the containers.

Her village, like so many in Cambodia, seemed a throwback to a bygone age: oxcarts rolling along vividly green rice fields and sugar palms shading clusters of wooden farmhouses on stilts.

But Cambodia's idyllic rural landscape is far from untouched by modern life. Pesticides such as mevinphos, dichlorvos and methyl-parathion made by European, American and Asian companies have penetrated into the remotest regions.

Many of these products are banned in their countries of origin -- and identified as extremely hazardous by the U.N. World Health Organization -- but they are being smuggled wholesale into Cambodia.

Activists contend that multinational corporations and smaller operators have made Cambodia and other poor countries a dumping ground for dangerous pest killers, a charge denied by manufacturers.

The pesticide business has boomed in Cambodia in recent years.

The Cambodian Center for Study and Development in Agriculture, known as CEDAC, recently catalogued at least 418 pesticide products on the market, 142 of which are legally banned or restricted in the country. Among these, fake and adulterated products abound.

CEDAC, a nongovernmental group, estimates sales could be as high as $20 million a year -- about double the national government's budget for agriculture.

Cambodia isn't alone. WHO says developing countries spend $3 billion a year on pesticides, about a third of which don't meet internationally accepted standards. It also reports 3 million acute pesticide poisonings each year and 220,000 deaths, 99 percent of them in developing countries.

Long-term effects of exposure to pesticides, by handlers and consumers, are believed to include damage to brain nerves, infertility, genetic mutations and cancer.

"Cambodia is one of the worst cases. They're quite vulnerable to the pesticide option without knowing what the hell they are doing," said Michael Shanahan, of the London-based Environmental Justice Foundation.

A generation of agricultural workers who could have guided farmers in proper pesticide use was wiped out during the Khmer Rouge terror of the mid-1970s, and the government remains weak, poor and plagued by corruption.

At the main market of Siem Reap, a major northwestern hub 140 miles from the capital, Phnom Penh, Vo Leak, a pesticides dealer, pointed to her five best-selling products.

All were on WHO's most dangerous list, four were banned in Cambodia and all had been smuggled from Thailand or Vietnam. Almost none of her wares had instructions printed in Cambodian.

"I don't know whether they're illegal or not, but they must be legal because they're imported," she said, adding that no government inspector had ever visited her stall.

A few miles away at Khnachas, a farmer, Hun Hoeun, said she believed her unborn child died from pesticides -- she sprayed during her pregnancy -- and she regularly suffers symptoms of pesticide poisoning, including vomiting, dizziness and headaches.

"We don't want to use pesticides," said the mother of nine. "But we [have] no alternatives. We are farmers. We have no other jobs."

Alternatives such as integrated pest management and organic farming reach only a small fraction of Cambodia's farmers, who grow mainly for the Cambodian market or their personal consumption.

In Hun Hoeun's village, about 80 percent of the more than 200 families apply pest killers, mostly on vegetables, and it is the women who do the spraying while men work in the rice fields or in town.

Hun Hoeun said the women learn about pesticides by trial and error and from the sellers. CEDAC's interviews with 77 traders in the Khnachas region found that only eight could read the product labels in foreign languages and just one had received training in pesticide use.

Farmers concoct their own chemical brews, sometimes mixing a dozen or more pesticides with hopes of maximizing potency and eradicating pests that have become resistant to repeated spraying of one formula.

Few farmers use boots, gloves and masks because of the cost and heat, and most don't change their clothes after spraying, according to the U.N. Food and Agriculture Organization. Pesticide containers sit around fields and houses, often near cooking areas and within reach of children.

Researchers say that beside harming farmers and consumers, the pesticide deluge is beginning to degrade such ecosystems as the Tonle Sap, Southeast Asia's largest lake and a crucial source of protein for Cambodians. The lake harbors about 500 species of fish and a rich variety of birds.

At Sro Maul Thom village, farmers said they abandoned mung bean cultivation because of the cost and health hazards of pesticides.

But pest eradicators, which wash into the lake, continue to be used. Soth Dam, a 43-year-old farmer, said he sprays Folidol on his watermelons.

He described it as "only medium dangerous." In fact, Folidol, a brand name for methyl-parathion, is classified as extremely hazardous and has been banned in Cambodia since 1998.

Produced by Bayer, Folidol remains one of the most popular pesticides, and is a major target of consumer activists.

Bayer and the Peruvian government face a class action suit arising from the 1999 deaths of 24 schoolchildren in a remote Andean village who inadvertently drank milk mixed with Folidol. The government later banned the product, which was labeled in Spanish, a language the illiterate or Quechua-speaking peasants couldn't read.

Russ Dilts, a former FAO official, accuses Bayer of dumping dangerous products that are difficult to sell elsewhere.

Bayer denies the allegation.

"We are aware that the product is there, and it is a matter of concern. This would not be a product we would register in Cambodia. First of all, it's banned, and we know people are not aware of how to use it," said Rolf Dieckmann, who heads Bayer's Southeast Asian operations.

He said Bayer could not control the smuggling of its products into Cambodia and added that the company would be seen as promoting the pesticides if Cambodian-language instructions were put on its cans. "We don't dump products in underdeveloped countries," he said.

Dieckmann said methyl-parathion is still legally used in Thailand and 30 other countries, including the United States and Australia, and is useful in certain carefully controlled situations.

But in Cambodia, a combination of ignorance among farmers and poor law enforcement spells grave trouble, said Ngin Chhay, an Agriculture Ministry official.

"It is not fair to just blame everything on the small traders for importing the chemicals because they, too, seem to know little about them," he said. "Major producers must understand the danger they are causing."

A Cambodian farmer drives his buffalo cart through the flood lands of Tonle Sap lake. Pesticide use has penetrated the country's remotest regions and researchers say sensitive ecosystems like Tonle Sap are being degraded. Activists say Cambodia has become a major dumping ground for pesticides by major companies. Cambodian farmer Seuon Siap, 50, watched by her daughter, mixes pesticides that she is about to spray onto her vegetable crop.Vo Leak displays commonly sold pesticides at her market stall in Siem Reap, 140 miles from Phnom Penh, the Cambodian capital. Second from left is Folidol, a brand name for methyl-parathion, which the World Health Organization classifies as extremely hazardous. It is produced by the German chemical company Bayer. Seuon Siap sprays a cocktail of pesticides on her crop, even though she cannot read the foreign language instructions for their use.