BANGKOK - Thailand's most popular fruit, the papaya, is the subject of a heated debate here on genetically modified (GM) crops - an issue that will be taken up at a global environment conference in Bangkok this week.

The issue has pit environmentalists against biotechnology advocates, with Greenpeace hauled off to court and activists threatening to call protests if the government goes down the GM path. The flare-up comes as the World Conservation Union, also known as the IUCN, gets ready to hold its Third World Conservation Congress in the Thai capital on Wednesday. The IUCN global congress, to be held from November 17-25, brings together 81 states, 114 government agencies, 800-plus non-governmental organizations (NGOs) and some 10,000 scientists and experts from 181 countries.

At the IUCN's second congress in the Jordanian capital of Amman in 2000, the world body had two key concerns over GM crops. First, it addressed the potential for significant reduction or loss of biodiversity when genetically modified organisms (GMOs) are released into the environment. Second, it noted that the potential of GM crops for "achieving global food security" had "not been adequately demonstrated so far".

In late July, Greenpeace reported that a government research station in the northeast province of Khon Kaen planting GM papaya was the source of contamination for farms in the area. On July 27, environmental activists, dressed in protective suits, trespassed into the government field research station and began removing GM papaya fruit from trees and securing them in hazardous material containers inside the field-trial site.

The department of agriculture moved to take action against Greenpeace for property damage. On November 8, key members of the group appeared at the Khon Kaen Provincial Court to answer charges. "The government is fighting tooth and nail to cover up the fact that it is the cause of the environmental disaster currently plaguing Thai papaya farms," Greenpeace Southeast Asia executive director Jiragorn Gajaseni told reporters after the case came up in court.

The environmental group said it had valid concerns when it twice tested batches of papaya seeds, from native species Khak Dam Tha Phra, sold by the research station to farmers. "Independent laboratory tests have shown that packages of papaya seeds being sold by the department of agriculture's own research station contain genetically modified seeds," said Varoonvarn Svangsopakul, Greenpeace's GMO campaigner.

"The experimental field, surrounded only by barbed wire and banana trees, was identified by Greenpeace as the source of the genetically modified seeds," she added. "The government must act now to impose a total ban on GM crop field trials - including those in government restricted areas and experimental stations."

Added Witoon Lianchamroon, director of BioThai, an environmental group working on the preservation of biodiversity in Thailand: "It has become very clear to the Thai people that we cannot allow a small group of scientists, or even the government, to take decisions on their own about running field trials of GM crops."

"The best way to control contamination is to stop all GM field trials," he stressed. "When GMOs leak into the environment - and it doesn't matter if they are approved or unapproved - no one can control pollination and no one can prevent contamination. This causes problems not only in terms of food safety, but with our whole food system."

Last month, the World Health Organization suggested that Thailand conduct further research on GMOs so that an early action plan can be implemented to cope with possible health risks posed by transgenic food. But the main frustration environmentalists face is dealing with Thai Prime Minister Thaksin Shinawatra, who seems to be vacillating in his decision on the commercial growth of GM crops.

On August 21, the premier angered environmentalists, farmers' groups and consumer networks by reversing a 2001 ban on the planting of GM crops. Ten days later, he undid his August 21 decision and opted for a national committee of academics to look into the matter. But to date, there has been no movement on this. "If Thaksin doesn't stop GM crops, we will stop him from having another term as prime minister," warned BioThai's Witoon.

GM papaya is genetically engineered to be resistant to the ringspot virus. It is made by cutting a gene from the ringspot virus and forcing it into papaya cell. This is done by randomly shooting the gene millions of times with a gene gun with the hope that it gets into the plant cell. Virus and bacteria resistant to antibiotics are also added, which is why sceptics are concerned about human health risks from the build-up of such resistance.

"Even if there has been some testing, the long-term effects to humans are unknown. We are still in the dark about the full ramifications of modified genes escaping and mixing with unmodified ones," said Janet Cotter, a Britain-based scientist working for Greenpeace, in an interview. But Prung Pomkoed, who owns a celebrated papaya orchard in Nakhon Chaisi, a district of the central plains province of Nakhon Pathom, said some farmers might prefer the GM strains because they are easier to maintain.

"The reason that people like to grow GM papayas is that they're 90-100% immune to the papaya ringspot virus. Usually there's no way to prevent this virus from attacking trees," he told the Bangkok Post, an English-language daily. "When it appears, it takes the form of white circles [on the leaves] and eventually causes the plants to rot and die. It spreads quickly, carried by a tiny fruit fly.

"The only way to counter it is to use insecticide to exterminate the fruit flies, which amounts, at best, to damage control," said Prung. In a bid to bring back farm productivity lost due to disease, scientists in Malaysia, Indonesia, the Philippines and Vietnam are also developing transgenic papaya resistant to ringspot virus. But unlike Thailand, which has already started fi eld trails, these other Southeast Asian countries are only at the greenhouse testing stage of GM papaya strains.