Establishment of Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae) as a bio-control agent for controlling eucalyptus pest Glycaspis brimblecombei Moore (Hemiptera: Aphalaridae) in Uganda

Abstract

The global demand for Eucalyptus trees has increased due to their utility in producing timber and energy. However, the trees face the threat of invasive pests like the Red gum lerp psyllid (Glycaspis brimblecombei). To address this issue, Psyllaephagus bliteus was introduced in Uganda in 2017 to control the Red gum lerp psyllid. A recent study evaluated the parasitoid's establishment in the country by collecting samples from 10 release sites across Uganda from August 2018 to December 2021. Infested leaf samples were collected from various parts of the Eucalyptus tree crown and the number of G. brimblecombei nymphs were counted. The study found that mummified nymphs of G. brimblecombei were observed in all 10 release sites and even as far as 179 km away from the nearest release site. Parasitized nymphs of G. brimblecombei were found on both plantations and standalone trees, with no significant parasitism differences on different leaf surfaces or along the tree crown. These findings suggest that P. bliteus has been successfully established in Uganda and has the potential to substantially control G. brimblecombei. However, it is crucial to further study the social and economic impacts of the parasitoids.