Nearly 80% of the world's cocaine comes from Colombia

Those who will be on the receiving end of this fumigation process say that it will cause only more hunger, poverty and war.

Indeed, it may even feed the guerrillas it is designed to attack.

Manuel Alzate Restrepo, the Mayor of Puerto Asis, one of the largest towns in Putumayo, calls Plan Colombia 'the Plan against Colombia'.

While President Andres Pastrana of Colombia and US President Bill Clinton see the plan as a foundation for peace, Mr Resrepeo sees "only more war and suffering".

Concerns

At a peasant association meeting in Puerto Asis, people are despondent.

We have seen what happened in Puerto Guzman ... there were people who died because of fumigation

Cecilia Anaya, Peasant representative

They feel that they are going to be the victims of the new US military aid package of $1.3bn, aimed at eliminating the drug crops in Putumayo.

The region is home to some 60,000 hectares of coca, the raw material for cocaine.

Cecilia Anaya is the president of Puerto Asis' peasant association.

"We have seen what happened in Puerto Guzman where they did the first fumigation tests," she says.

"There were people who died because of fumigation, who lived mainly by growing yucca, plantain and rice."

"And now there is misery, hunger and displacement. So we are very worried."

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Much of the coca grown in Putumayo is grown by peasant farmers with a few hectares of fields carved from the jungle.

They grow coca as a cash crop alongside pineapples, maize and other subsistence crops.

However, the chemicals dropped by the US-supplied planes cannot distinguish between the different crops.

This means that the livelihood of peasants - already living well below the poverty line - ends up in ruins.

As well as destroying crops other than coca, Esteban Torres, the local schoolteacher says there is evidence that the chemicals dumped on Putumayo's fields are damaging the inhabitants.

"There is no running water in Puerto Guzman," he says.

"And the people drink water from the streams which pass alongside the fields, so when the planes fly over spraying these toxic chemicals, people are drinking this water or preparing their food with it and falling sick."

Poisoning

A coca farmer inspects his crops

His assertion is confirmed by Marta Cecilia Guapacha, the head nurse at San Francisco hospital in Puerto Asis.

She has treated too many patients in the immediate aftermath of crop spraying to think coincidence is at work.

"We have had cases of poisoning because of the chemicals, lots of skin rashes, eye conjunctivitis, children more than any, and breathing problems after having inhaled the toxic chemicals," she says.

The effects of aerial eradication on the environment are also said to be frightening.

After fields have been sprayed, crops cannot be grown there for many months afterwards.

Peasants, having lost their food crops as well as the coca, cut down more jungle to replant.

'Illicit crops greatest threat'

Colombian Environment Minister Juan Mayr has admitted that there are serious environmental concerns.

For the young, there is no other alternative, there are no jobs, they go to the guerrillas.

Esteban Torres, schoolteacher

However, he refuses to acknowledge that the US-inspired eradication programme is responsible.

"The Ministry of Environment has come to see illicit crops as the greatest threat to the disappearance of Colombia's biodiversity," he says.

"These crops in the last decade have produced the deforestation of close to a million hectares."

As well as damage to health and the environment, there is evidence that the fumigation programme is not really hurting the guerrillas, but rather providing them with more recruits.

Mr Torres tries to contain his tears as he relates what happened to Puerto Guzman after the aerial eradication.

"Then the people, the youth, including two ex-students of mine, girls, left school to join the guerrillas," he says.

"For the young, there is no other alternative, there are no jobs, they go to the guerrillas."