New pest emerges
In May this year symptoms of a previously unreported insect pest was detected on Eucalyptus in Midrand, Gauteng, reports Brett Hurley of the TPCP. While the symptoms appeared similar to those of some Ophelimus species, no gall formers emerged in captivity until recently.
The species name must still be confirmed, but the symptoms and adults that have now emerged indicate that it might indeed be Ophelimus maskelli, which is a known pest of Eucalyptus in the Middle East, Europe, North Africa, Mauritius and New Zealand (native to Australia).
The collections of infected leaves originally only resulted in the emergence of Closterocerus chamaeleon, a known larval parasitoid wasp of O. maskelli. Furthermore, a Tetrastichinae wasp (still to be identified) has also emerged from the galls, which is also thought to be a parasitoid of the gall former.
Work by the TPCP is ongoing to confirm the identity of this new pest, understand the threat it poses to Eucalyptus forestry, and investigate possible responses including biological control.
It is important to obtain information on the spread and host association of this new pest outside Midrand. Foresters to please notify Dr Brett Hurley (brett.hurley@up.ac.za) should they notice the symptoms of this pest in their plantations.
Update on Bronze bug biocontrol
The tiny mymarid parasitic wasp, Cleruchoides noackae, biological control agent for the bronze bug, Thaumastocoris peregrinus, has been released at 27 sites across the country over the past year, with more releases to follow.
These releases follow six years of intensive research at the FABI Biocontrol Centre, University of Pretoria, to study the biology and host specificity of this insect, that eventually culminated in the successful application for its release in South Africa.
Post-release monitoring to determine the establishment of C. noackae at these sites has been difficult due to the sporadic nature of the host pest T. peregrinus, but efforts will continue to assess the success of the releases.
Brett Hurley brett.hurley@fabi.up.ac.za