Wasp controls pest threatening Ethiopia’s tree plantations

12/08/2009In cooperation with the Government of Ethiopia, FAO introduced a parastitic wasp to control a fast-spreading aphid pest infestation threatening to destroy cypress tree plantations in parts of North Western and South Western Ethiopia.
The death of cypress trees was first observed in Ethiopian in 2003; aphids kill them by sucking their sap. Traditional control measures such as regular watering and pruning proved ineffective and use of aphicide spray was not economical. Ethiopian scientists backed by the FAO Subregional Office in Addis Ababa targetted badly damaged cypress plantations in the Amhara and Tigray Regions. The female wasp known as Pauesia juniperorum uses the aphid as a host for its eggs which hatch into larvae that feed on the pest’s internal organs and kill it.
“FAO promotes the most sensible and affordable but reliable science to address agriculture and natural resource issues,” said Mafa Chipeta FAO Sub-regional co-ordinator for Eastern Africa. “Ethiopia’s forests are precious environmental and economic assets already under siege from encroachment and climatic factors. Successful, cost-effective pest control measures are fundamental to maintaining the country’s healthy forests.”
The wasps were imported from Kenya to be reared by the Arsi Forest Enterprise in Ethiopia and experiments were undertaken to ensure release of the wasps would have no negative effects on the Ethiopian environment nor create any problems for humans, animals or beneficial insects. Once it was ascertained the wasps could not lay their eggs in honey bees, silkworms, spiders or ladybird beetles, the wasp was released in aphid affected forests, hedges and trees in November 2008. There was good co-operation with a project funded by the African Forest Research Network.
In June 2009, FAO conducted a monitoring and evaluation mission which found that almost all of the target hedges and trees had since recovered and had resumed good growth. The recovery of the cypress trees in Hugem Berda forest of southern Tigray was particularly successful with a forest technician describing the results as an “amazing performance”.
For further information contact: sophie.gordon@fao.org + 251 910 218 357