Breaking news: Biological control agent for Thaumastocoris peregrinus to be released in South Africa
The Tree Protection Co-‐operative Programme (TPCP) based at FABI has
recently received permission from the Department of Agriculture,
Forestry and Fisheries (DAFF) and the Department of Environmental
Affairs (DEA) to release the parasitic wasp Cleruchoides noackae (Mymaridae), for the biological control of the Bronze Bug, Thaumastocoris peregrinus.
This is an incredibly important milestone in terms of ensuring
sustainable plantation forestry in South Africa and it marks the
culmination of a long and often tedious process involving amazing
commitment and effort on the parts of many people.
Cleruchoides noackae was first imported into the FABI Biocontrol
Centre at the University of Pretoria in 2008. This minute parasitic wasp
(less than 0.5mm in length) is extremely difficult to rear, in part
because it is very delicate and thus difficult to handle. It was only
after considerable efforts to develop new rearing techniques that
studies on its biology and host specificity could commence. These
studies, which needed to be carried out with meticulous detail, provided
the first study of C. noackae biology (now published) and showed that C. noackae was host specific, and thus safe for release.
An application for permission to release C. noackae was submitted to DAFF by FABI on behalf of the forestry industry in January 2013. After in depth review it was concluded that C. noackae was safe to release in South Africa as a biological control agent.
The release strategy for C. noackae in South Africa must still be
finalized. But, it will likely follow a similar classical biological
control approach to that used with Selitrichodes neseri, the biological control agent for Leptocybe invasa
developed and released by the TPCP in 2012. Thus releases will most
likely be made as broadly as possible and the released individuals will
be expected to establish and spread in those areas.
At this stage it is impossible to know what mpact C. noackae will have on T. peregrinus populations. But, C. noackae
has been released as a biological control agent in Chile and Brazil,
and preliminary results show that the insect has established well in
these areas. Clearly post-‐release monitoring will be required to
determine the success of the releases and the rate of establishment of C. noackae in South Africa.
Many people and organizations have contributed to the considerable effort that has lead to this point where C. noackae
can now be released. However, special thanks are due to the members of
the TPCP and particularly the TPCP Board, who have supported the work
both financially and otherwise; the Department of Trade and Industry
(DTI) through their THRIP initiative; the National Research Foundation
and the University of Pretoria for financial support; the staff of DAFF,
who dealt speedily and professionally with the application for release;
Prof. Stefan Neser who, together with Ryan Nadel of the ICFR as part of
his Ph.D. at FABI, assisted in importing the original C.noackae into South Africa, and has provided incredible guidance in the rearing and experimentation of C.noackae from 2008-‐2013; Ryan Nadel and Eston Mutitu who added substantially to the understanding of C. noackae during their Ph.D. studies; Dr Annie Noack (Australia) for providing invaluable advice on the rearing of C. noackae and who has sent numerous consignments of C. noackae to the FABI Biocontrol Centre for study, and last but not least, the
technical staff of the FABI Biocontrol Centre, in particular Marlene
Harney and Samantha Bush, together with Joseph Khadile, Tanya Joffe, and
a number of NMMU students, whose great dedication and ingenuity has
made thisrelease possible.
|A male C. noackae. This family of wasps (Mymaridae)
are also known as ‘fairyflies' because of their delicate wings (photo: S. Bush).
|A female C. noackae ovipositing into an egg of T. peregrinus (photo: S. Bush).
|Techniques used to rear and study the biology of C. noackae.
|Marlene Harney, Eston Mutitu, Tanya Joffe and Anne Noack in discussion at the FABI Biocontrol Centre.
The Pest: Thaumastocoris peregrinus
Thaumastocoris peregrinus is a sap-‐sucking insect that feeds on Eucalyptus
leaves and is native to Australia. This bug (a true bug of the Order
Hemiptera) was virtually unknown in its native range until 2002, when it
became a pest in the Sydney and Brisbane areas. This build-‐up of
populations in large centres in Australia most likely contributed to its
spread to South Africa.
Thaumastocoris peregrinus was first noticed in South Africa in 2003 in the Pretoria area. It was first reported in Eucalyptus plantations in 2005, and was soon present in all the main Eucalyptus growing areas. The insect infests numerous Eucalyptus species,
hybrids and their clones. Severe infestations can lead to canopy
thinning, branch die-‐back and stunted growth of the trees. Chemical
control and host resistance are not viable, and biological control is
currently considered the only tool to manage T. peregrinus populations.
|Thaumastocoris peregrinus - eggs and adult
|Damage caused by T. peregrinus.
Researcher and Senior Lecturer
Department of Zoology and Entomology
Tree Protection Cooperative Programme (TPCP)
Forestry and Agricultural Biotechnology Institute (FABI)
University of Pretoria
Phone: +27 12 420 5822
Fax: +27 12 4203960