Plan to stop invasive Mathenge weed spread

Dead Flamingos hanging on trees at Lake Bogoria National Reserve in Baringo county. At least twenty thousand flamingos have died while stuck on Mathenge trees since swelling water pushed them to the shores. [Kipsang Joseph, Standard]

Plans are underway to control the spread of the invasive prosopis juliflora, locally known as Mathenge, in arid and semi-arid areas.

The national strategy and action plan for the control of Mathenge will incorporate use of biological agents to limit seeding and growth rates. The plans also involve use of chemicals to kill young plants, besides use of the plant through charcoal burning.

Mathenge is an invasive plant native to South America and was intentionally introduced for its adaptability to desert conditions and fast growth. It is also a source of fuelwood, livestock fodder, human food and bee forage.

However, the plant has progressively become invasive, colonising many arid and semi-arid areas.

Uncoordinated strategy has led to the rapid spread of the plant. “Despite these noble efforts intended to manage prosopis juliflora invasions through utilisation, the species has continued to spread at an exponential rate of between 4 per cent to 15 per cent per year with devastating negative consequences on ecosystem services and livelihoods of pastoral communities and farmers,” part of the strategic plan reads.

It is estimated that Mathenge currently covers about 1,165,771ha and is found on public, community and private land. The largest invasion of the species in Kenya is in Turkana, Tana River, Garissa and Baringo counties.

The weed is also found in Taita Taveta, Kilifi, Samburu, Isiolo, Mandera, Marsabit, Wajir, Kajiado, Kwale, Lamu, Tharaka Nithi, Meru, Mombasa, Kitui and West Pokot counties.

Following its vast spread, Mathenge has been declared a menace as it blocks roads, river systems and irrigation canals while encroaching on farming and grazing lands, national parks, game reserves and institutional compounds. Areas highlighted as worst affected include Bura, Perkerra, Lororro and Katilu irrigation schemes. It has also affected fishing in Lake Baringo and Lake Turkana as it covers most landing bays.

Mathenge has also contributed to livestock deaths occasioned by excess sugar-laden pods or through starvation as it causes rotting and loss of teeth. Its strong, long thorns also cause injuries for diabetic persons. “It is widely accepted that this situation is a direct result of the absence of a coordinated management strategy,” the strategy notes.


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