Latest News Archive

Please select Category, Year, and then Month to display items
Previous Archive
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.

Other interesting material

News Archive

Researcher takes home gold at international Famelab competition
2017-06-26

Description: Famelab competition Tags: Famelab competition

UFS researcher nabbed a top international award for
her ground-breaking metallurgical research in the UK.
Photo: Supplied

Recently, University of the Free State (UFS) Centre for Environmental Management master’s student, Tshiamo Legoale, was announced the FameLab International champion at the Cheltenham Science Festival in the United Kingdom. She is probing methods to use wheat as a gold hyper-accumulator – or, as she puts it, “grow gold from wheat”. The young researcher made South Africa proud by winning both the audience’s and the judges’ vote.

Coming back home a hero
“Winning was a surprise to me, because all 31 contestants had wonderful research. They all had really good presentations. I’m very grateful for all the support that I received from home. Social media showed me a lot of love and support. When I felt unconfident, they gave me ‘likes’ and that boosted my confidence a bit,” said Legoale about her win.

As South Africa celebrates Youth Month in June, Tshiamo represents hope for thousands of young South Africans to overcome difficult circumstances and follow careers in science.

The human impact is crucial, because Legoale’s win is not only scientific. It is also social and political. As a young female scientist in South Africa, she represented one of three African countries making it to the finals of FameLab, which has grown to one of the largest science communication competitions internationally.

With this in mind, Legoale says it may, in the end, be necessary to balance the needs of communities with the desire to increase yield. “Are we looking to make a fortune or are we looking to put food on the table?” she asks. “These are all things we consider when we conduct such research.”

World-class research from Africa
In South Africa, an estimated 17.7 million tons of gold is wasted. “All this gold was mined out previously, but tiny amounts remain in the dumps,” Legoale explains.

Her research focuses on the uses of wheat as a gold hyper-accumulator, which essentially means wheat plants are used to harvest gold from mine dumps. Simply put, the wheat is planted in the dumps, where enzymes found in the roots react with the gold and the plant absorbs it. The gold is then absorbed by every part of the plant, except the seeds, which means the next harvest can be used for food if need be.

“South Africa's world-champion young scientist, Tshiamo, represents all that is good about this country – brilliant, bright, and set for a fine future. I'm so proud that British Council SA, together with our partners SAASTA and Jive Media Africa, can help her along the way. Huge congratulations to her from all of us – it is a big win for Africa on the world stage,” said Colm McGivern, British Council South Africa Country Director.

The research represents a win on multiple levels. First, there are the obvious potential socio-economic benefits: food production, job creation, and phytomining is more economical than other contemporary mining methods.

Then there is safety. It is a more environmentally friendly practice than methods like heap leaching, carbon-in-leach or carbon-in-pulp. It is also safer for miners themselves, who will not be exposed to dangerous chemicals like mercury, which has been responsible for a great deal of toxicity in mine dumps. And it is safer for those living in the surrounds.

We use cookies to make interactions with our websites and services easy and meaningful. To better understand how they are used, read more about the UFS cookie policy. By continuing to use this site you are giving us your consent to do this.

Accept