Scientists are claiming a success against a water weed that was choking the economic life from Africa's biggest lake.

Weevils released three years ago by Kenya, Uganda and Tanzania, are said to have wiped out 60% of the water hyacinth on Lake Victoria.

While other methods of control such as physical removal are still being used, the weevils are said to be the most effective solution.

Economic disaster

Fertiliser run-offs from lakeside farms provided ideal conditions for the water hyacinth, which reproduced in Lake Victoria at a phenomenal rate.

From being virtually unknown at the beginning of the decade, by 1996 it had become a major economic headache and an apparently overwhelming disaster.

At its worst, it was possible to see the dark green leaves extending like a well laid carpet to the far horizon.

After Kenya, Uganda and Tanzania finally agreed a joint approach, weevils were imported from South Africa, Australia and West Africa.

Local people were promised relief within five years, but according to Doctor Andrew Mailu of Kenya's Agricultural Research Institute, the problem should be resolved well within that time.

He said the weevils only feed on hyacinth and their numbers will decline as the weed is killed off and increase if it makes a comeback.

He said the main problem now was how to deal with the critical levels of pollution from industry, farms and towns.