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

Inaugural lecture: Prof André Pelser
2004-06-04

Tendencies and changes in the South African population structure in future decades.

Within the next five years South Africa will for the first time in the past century enter a period where the death rate will exceed the birth rate, largely due to the impact of HIV / AIDS.

According to sociologist Prof André Pelser, sociologist at the of the University of the Free State’s (UFS) Department of Sociology, the death rate exceeding the birthrate is only one of three demographic trends which will fundamentally change South Africa’s population structure in the following decades.

He was speaking at the UFS in Bloemfontein during his inaugural lecture as professor this week.

Prof Pelser said that according to some models the South African population will decrease within the next five decades by between 10 and 26 percent.

A second important trend which will impact on the population structure is the progressive ageing of the population.

He said the group above 65 years is the only age category in the South African population which will witness sharp increases in the next few decades.

In the next 50 years, the group younger than 15 years will reflect a decrease of 39% and those older than 65 years in South Africa will increase by approximately 110% in the next two decades.

“The systematic “greying” of the South African population will create the same economic and welfare issues as those with which governments in some more developed countries are already grappling,” said Prof Pelser.

A third trend affecting the South African population structure is the constant decrease in life expectancy.

Life expectancy at birth for the total population is projected to decrease from approximately 62 years at the beginning of the 1990’s to 43 years in 2015-2020, with sharp differences between the various population groups.

These tendencies and changes to the South African population structure have serious implications, he said.

For example, he said, the reduction in life expectancy could compromise national development objectives.

“It is estimated that more than a quarter of the economically active population will be infected with HIV by 2006,” said Prof Pelser.

The increase in the population, in age category 65, will place a financial burden on government and the economically active sector.

“Especially worrying is the fact that ever-increasing proportions of the state budget will be allocated to health and welfare services and this at the expense of other priorities like education, infrastructure, criminal justice system and trade and industry, to name but a few,” he said

“A comprehensive and integrated strategy is thus vitally important in addressing the overarching issues caused by changes in the population structure,” said Prof Pelser.

 

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