QUITO - Officials and researchers are attempting to eradicate the Castilla pigeon from the Galápagos Islands within two years. The bird species is not native to this unique ecosystem and has caused environmental damage to the Ecuadorian archipelago.

The effort - promoted by the Galápagos National Park and the Charles Darwin Research Station - began on Santa Cruz island, where 350 Castilla pigeons have been identified. The birds have spread diseases like salmonella to the native pigeons and doves, and even to humans.

On San Cristóbal and Isabela islands, also part of the Galápagos, experts are working to determine the size of the pigeon population and have launched an environmental education campaign to win support from the local population for the eradication measures.

MEXICO CITY - The herbicide known as Paraquat, banned in many countries due to its high toxicity, is being used in Mexico to wipe out illegal marijuana plantations.

The Attorney General's Office has purchased 95,000 liters of Paraquat this year despite the fact that the government's National Commission on Human Rights identified the chemical last year as causing the death of one young girl and of intoxicating 300 indigenous people in the northern state of Chihuahua.

The Attorney General's Office, however, maintains that ''no contamination or poisoning of populations near the areas fumigated with Paraquat have been recorded.''

Environmental and human rights organizations charge that the dangers of this herbicide are well documented in Mexico and in other countries and are demanding that the government seek other methods for eradicating marijuana fields.

BOGOTA - Colombian researchers at the First International Congress on Medicinal and Aromatic Plans presented a standardized compound of banana, calendula, cabbage and lemon balm for fighting gastritis as well as stomach and duodenal ulcers.

It is ''a mixture of substances that deploy a combined action aimed at providing a definitive solution to the problem of gastritis or ulcers,'' explained one of the creators of this unique formula during the conference held in the city of Cali, Aug 16-19.

This ''medication'' was tested on 351 patients (258 women and 93 men), ages 14 to 72, with impressive results, according to their report.

HAVANA - Cuban and German scientists working in the mountainous region on the eastern extreme of Cuba have identified various species of 'buxus', a bush that has few known varieties in the world.

The discovery was made near the town of Ojito del Agua, more than 900 km from Havana. The experts found four different varieties of the plant within just 100 square meters of forest.

In Ojito del Agua and nearby villages, located on the Cuchillas del Toa Biosphere Reserve, scientists in the last few years have identified 30 plant and animal species that are rare or in danger of extinction.