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26 September 2019 | Story Leonie Bolleurs | Photo Leonie Bolleurs
Read More Prof Wijnand Swart PSHB
A small 2 mm beetle, known as the Polyphagous shothole borer (PSHB) kills and infects trees. South Africa is the largest geographical area in the world to be infested with this tree killer. Pictured here is Prof Wijnand Swart who is working with two neighbourhood associations in Bloemfontein to monitor the occurrence of the beetle in the city.

Ornamental trees are dying all over South Africa, and it is feared that certain fruit and nut trees are also in danger. This is cause for great concern, not only among ecologists, farmers, foresters, and landscapers, but for homeowners as well. In private gardens and on streets throughout the country, trees that are afflicted include English oak, Chinese and Japanese maples, boxelder, and sweetgum.
 
The cause of all this havoc is a small 2-mm beetle, known as the Polyphgous shothole borer (PSHB; Euwallacea fornicatus) that originates from Southeast Asia.

Working to find a solution

"Based on damage seen in the USA and Israel, there is significant danger of losing many of our ornamental trees as well as fruit and certain nut trees in South Africa,” says Prof Wijnand Swart, Professor of Plant Pathology and Discipline Head in the Department of Plant Pathology at the University of the Free State (UFS).

Cases of afflicted trees were reported from all provinces in South Africa, except for Mpumalanga. Countries such as Israel and the USA have also suffered great losses as a result of this beetle.  

Research is being conducted on the beetle and its associated fungus, Fusarium euwallaceae, in order to understand their relationship and hopefully find a solution to stop, or at least manage, the invasion of trees. To investigate the largest geographical outbreak of this beetle in the world, academics from seven universities in South Africa are working together with the Forestry and Agricultural Biotechnology Institute (FABI) at the University of Pretoria through a multi-institutional and multi-disciplinary research network. UFS researchers are part of this network.
 
Senior Lecturer in the UFS Department of Plant Sciences, Dr Gert Marais, is conducting research on the PSHB and its associated fungi, with the focus on pecan trees, in conjunction with the South African Pecan Nut Producers' Association. Cases of infected pecan-nut trees were reported in the Northern Cape as well as in Nelspruit. 
 
Prof Swart is working with entomologists in the UFS Department of Zoology and Entomology to find a biological control agent to parasitise the beetle. “I have already found one instance of a parasitic wasp associated with the beetle and will continue to search for more specimens during the coming summer,” he commented. 
 
Understanding the beetle

The first cases of infected trees were discovered in 2017 when Dr Trudi Paap, associated with FABI and the South African National Biodiversity Institute, conducted a survey of pests and diseases in and around National Botanical Gardens in South Africa. 
 
FABI has been studying the tree killer intensively to find out more about its life cycle. The term ‘polyphagous’ refers to the ability of the PSHB to infest many different tree species.

On their website, FABI states that an important distinction is being made between different types of infestations. “Reproductive host trees are trees that are infested by the beetle and where it successfully establishes a breeding gallery in which the fungus grows, where eggs are laid, and larvae develop into mature adults, thus completing its life cycle. The majority of reproductive hosts eventually succumb to the disease symptoms caused by the fungus.”
 
“Non-reproductive host trees are trees where the beetle attacks, penetrates, and inoculates the fungus, which then starts to grow in the sapwood. However, the beetle either leaves or dies without reproducing in these trees. The fungus can eventually kill or damage reproductive hosts, but many of the tree species on this list seem to be unaffected.”
 
Involving the community

The situation also provides an opportunity for communities to directly benefit from research conducted by tertiary institutions. Prof Swart is working together with two neighbourhood associations in Bloemfontein to monitor the occurrence of the beetle in the city and surrounding areas. 

He urges residents in the Mangaung Metro who find instances of infected trees, to report it to Duart Hugo (duarthugo99@gmail.com ), who is compiling a database of infected trees in the area. 
 
FABI advises homeowners to cut down heavily infested reproductive host trees. Should you decide to burn the wood, note that beetles will fly away when the wood becomes hot or when smoke appears. Do not burn infested trees in uninfected areas.

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News Archive

UFS to host one of three world summits on crystallography
2014-04-15

 
Prof André Roodt from the Department of Chemistry at the University of the Free State (UFS), co-unveiled a special plaque in Poznan, Poland, as president of the European Crystallographic Association, with prof Gautam Desiraju, president of the IUCr (front right) and others to commemorate the Nobel prize winner Max von Laue. (Photo's: Milosz Ruszkowski, Grzegorz Dutkiewicz)

Prof André Roodt from the Department of Chemistry at the University of the Free State (UFS), co-unveiled a special plaque in Poznan, Poland, as president of the European Crystallographic Association, to commemorate the Nobel prize winner Max von Laue at a special Laue Symposium organised by prof Mariusz Jaskolski from the A. Mickiewicz University in Poznan.

Max von Laue, who spent his early childhood in Poznan, was the first scientist to diffract X-rays with a crystal.

2014 has been declared by the United Nations as the International Year of Crystallography, and it was recently officially opened at the UNESCO headquarters in Paris, France, by the Secretary-General of the UN, Ban Ki-moon. The International Year of Crystallography celebrates the centennial of the work of Max von Laue and the father and son, William Henry and William Laurence Bragg.

As part of the celebrations, Prof Roodt, president of the European Crystallographic Association, one of the three regional affiliates (Americas, Europe and Africa; Asia and Australasia) of the International Union of Crystallography (IUCr), was invited by the president of the IUCr, Prof Gautam Desiraju, to host one of the three world summits, wherein crystallography is to showcase its achievements and strategise for the future.

The summit and conference will take place on the Bloemfontein Campus of the UFS from 12 to 17 October 2014 and is titled: 'Crystallography as vehicle to promote science in Africa and beyond.' It is an ambitious meeting wherein it is anticipated to bring the French-, English- and Arab-speaking nations of Africa together to strategise how science can be expanded, and to offer possibilities for this as nestled in crystallography. Young and established scientists, and politicians associated with science and science management, are the target audience to be brought together in Bloemfontein.

Dr Thomas Auf der Heyde, acting Director General of the South African Department of Science and Technology (DST), has committed some R500 000 for this effort, while the International Union of Crystallography provided R170 000.

“Crystals and crystallography form an integrated part of our daily lives, form bones and teeth, to medicines and viruses, new catalysts, jewellery, colour pigments, chocolates, electronics, batteries, metal blades in airplane turbines, panels for solar energy and many more. In spite of this, unfortunately, not many people know much about X-ray crystallography, although it is probably one of the greatest innovations of the twentieth century. Determining the structure of the DNA was one of the most significant scientific events of the 20th century. It has helped understand how genetic messages are being passed on between cells inside our body – everything from the way instructions are sent to proteins to fight infections, to how life is reproduced.

“At the UFS, crystallography finds application in Chemistry, Physics, Biology, Mathematics, Geology, Engineering and the Medical fields. Crystallography is used by the Curiosity Rover, analysing the substances and minerals on Mars!

“The UFS’s Departments of Chemistry and Physics, in particular, have advanced instruments and important research thrusts wherein X-ray crystallography has formed a central part for more than 40 years.

“Crystallography has produced some 28 Nobel prize winners over the past 100 years and continues to provide the means for fundamental and applied research,” said Prof Roodt.

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