Invasive pest spells death knell for region’s eucalyptus trees

Saturday February 18 2012


THE EUCALYPTUS tree known for its commercial purposes is under threat of extinction in three East African countries and South Africa, after invasion by a new foreign pest.

The tree used for electric poles, building materials and firewood is drying at an alarming rate in Western Kenya, South Coast, Rift Valley and parts of Eastern province after invasive Bronze Bug, (Thaumastocoris peregrines) invaded the country according to a report by Kenya Forest Research Institute (Kefri).

In Kenya, most affected areas are Lunga Lunga in Kwale County, Busia and Kibwezi, while central province and Nakuru are moderately affected according to Principal Entomologist at Kefri, Mr Eston Mutitu.

“I am currently doing a survey around the country. The eucalyptus tree is under a great threat unless something is done urgently,” he warns.

In Kenya, 300,000 hectares are under Eucalyptus in large and small scale farming.

According to research, the bug is sucking sap from leaves causing the tree canopy to redden in progressive attacks. During heavy infestation, trees lose their leaves while branch tips or the whole tree may die.

The attacks are intensive during dry season in the months of October and February.

The pest is attacking specific Eucalyptus species (Eucalyptus Grandis and hybrid clones) and was first reported in Kenya in November 2009 in Kiserian region, Kajiado county.

While it was not serious, it prompted Mr Mutitu to start his survey. In December last year, he says the pest spread drastically.  

“My biggest worry is that the Eucalyptus tree is now being attacked by two different pests,” said Mr Mutitu.

The other pest is Blue gum chalcid, (Leptocybe invasa) which is also invasive and is threatening the productivity of the Eucalyptus species.

The two have been found largely in Ethiopia but the bronze bug, says Mr Mutitu originated from Australia, spreading to Africa and South America.

From Ethiopia, the Bronze bug spread northwards to Zimbabwe in August 2007 and arrived in Malawi in June 2008, said the entomologist.

Kefri believes the pest spread to Kenya from Tanzania through herders who had gone to search for pastures and water for their livestock.