But once hailed as a miracle cure for land degradation and desertification, the rapidly spreading prosopis tree has become an environmental menace that many wish had never been introduced to the east African nation.

And having been brought to Kenya from the Americas in a much-lauded two-decade-old programme, authorities are now importing another non-indigenous species -- a leaf beetle known to eat prosopis seeds -- to curb its growth.

In the early 1980s, the Kenyan government, with financial backing from the UN Food and Agricultural Organisation (FAO), encouraged the planting of prosopis trees with an eye toward sustaining life in arid and semi-arid zones.

But more than 20 years later, it has overgrown its welcome and objectives, blocking off pathways and stooping over rural roads as well as altering river courses, some of which now meander through homesteads.

"The river used to be six kilometers (four miles) from here," says Joel Olesaaya, a local councillor in this village in Baringo district, 300 kilometers (185 miles) northwest of Nairobi where prosopis trees run rampant.

"Now, it is in my field and my house is flooded on a regular basis, I had to move," he said, as wandered round his corrugated tin house that is often marooned by surging river waters.

With a countrywide coverage of between 500,000 and a million hectares (1.2 to 2.5 million acres), the thorny deciduous tree has forced 113 people from their homes in Ngambo alone as it overwhelms efforts to curtail its growth.

"The problem is that prosopis is very aggressive, it grows on its own," said Simon Choge, an official with Kenya Forestry Research Institute. "It is now out of control. It is an invasion."

Its sweet and alluring fruit has also proved a fatal attraction for browsing livestock, at least 1,000 of which have died as a result of eating the green-bean like produce that turns pale yellow when ripe, residents say.

"The pods are too sugary, the goats lose their teeth and die," said Wesley Lekakimon, a Ngambo resident, who like many see the benefits of the prosopis explosion as being far outweighed by its ubiquity.

While acknowledging the problems, government officials have urged patience, noting that the trees can be used to benefit communities.

"Prosopis is a problem now, but the challenge we have is how to manage and utilise it," allowed David Mbugua, the chief conservator of forests with Kenya's environment ministry.

Yet angry locals are demanding action to fight back after attempts to take advantage of a bad situation by felling the trees and using the wood to make charcoal and the fruit to make cattle feed proved not worth the expense.

"I have made 3,000 Kenyan shillings (42 dollars, 35 euros) in the past six months," said Eresia Merige a local farmer who has been trying in vain to eke out a living from the labor-intensive process.

Choge shares her frustration.

"It is hard to mobilise people because of the intensity of the work and you don't get anything at the end of the day," he said.

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