Latest News Archive

Please select Category, Year, and then Month to display items
Previous Archive
07 August 2025 | Story Martinette Brits | Photo Stephen Collett
Prof Willem Boshoff
Prof Willem Boshoff shares insights from decades of rust disease research during his inaugural lecture at the University of the Free State.

Rust diseases of food crops remain one of agriculture’s most enduring and evolving challenges. In his inaugural lecture on 23 July 2025 at the University of the Free State (UFS), Prof Willem Boshoff shared how these complex pathogens continue to pose a significant threat to South Africa’s staple crops – and why continued research is more critical than ever.

Titled Battling rust diseases of food crops in South Africa, the lecture reflected on decades of rust research and recent developments in pathogen virulence. Prof Boshoff, from the Department of Plant Sciences, emphasised that the threat posed by rust fungi today stems from their “mechanisms of variability, their ease of long-distance spore dispersal, and subsequent foreign race incursions”.

 

A shifting disease landscape

Rust fungi are biotrophic organisms that cannot be cultured on artificial growth media. This makes rust research a technically demanding field that requires living pathogen collections, seed sources, skilled researchers, and specialised infrastructure. Prof Boshoff noted that for more than 35 years, the UFS has been at the forefront of this work, monitoring rust pathogens on wheat, barley, oats, maize, and sunflower.

While wheat remains the most extensively studied type, recent rust outbreaks across a range of crops point to a worrying trend. A localised outbreak of stem rust on spring wheat in the Western Cape has been linked to race BFGSF, which carries a previously unknown combination of virulence genes affecting both wheat and triticale. In 2021, leaf rust race CNPSK was detected, showing virulence to the highly effective Lr9 resistance gene.

More recently, stripe rust race 142E30A+ – first reported in Zimbabwe – was found in wheat cultivars from the Free State and northern irrigation areas. “Results revealed increased susceptibility of especially spring irrigation wheat cultivars,” Prof Boshoff explained, particularly due to its virulence to the Yr9 and Yr27 resistance genes.

Rust pathogens affecting other crops are also evolving. In maize, only a few lines with mostly stacked resistance gene combinations were effective against all tested isolates. In sunflower, just four of 30 Agricultural Research Council national trial hybrids showed resistance to local rust races.

 

Building better resistance

A key strategy in rust control lies in identifying and understanding resistance in host plants. This, Prof Boshoff stressed, requires optimised phenotyping systems for both greenhouse and field conditions, along with a solid understanding of available resistance sources. At the UFS, several recent studies have contributed valuable data to both local and international plant breeding programmes.

“Continued local and regional rust research is critical,” he said. “It supports early detection of new races, alerts to producers through updated cultivar responses, and enables efficient breeding strategies and other sustainable methods of rust management.”

The rust programme at the UFS has not only supported varietal release and on-farm risk management, but also strengthened collaboration between plant scientists, industry partners, and international researchers. With South Africa’s strategic location and history of rust surveillance, the programme continues to play a pivotal role in continental and global food security efforts.

 

About Prof Willem Boshoff

Prof Willem Boshoff is a plant pathologist with a strong background in wheat breeding and rust disease control. He holds four degrees from the University of the Free State, all awarded cum laude: a BScAgric (1994), BScAgric Honours (1995), MScAgric (1997), and PhDAgric (2001). His doctoral research focused on the control of foliar rusts in wheat.

Between 2001 and 2016, he worked as a wheat breeder and contributed to the release of several commercial cultivars. He joined the UFS Department of Plant Sciences in 2017 and has since been actively involved in national and international research projects, capacity development, and advancing disease resistance in food crops.

News Archive

Plant eco-physiologist finds effective solutions for crop optimisation
2016-07-24

Description: Orange trees Tags: Orange trees

The bio-stimulant was tested on
this citrus. This is the first time
that the product has been tested
on a crop.

In a time characterised by society facing increasing population growth, food crises, and extreme climatic conditions such as drought, it is essential for farmers to integrate science with their work practices in order to optimise crops.

Role of photosynthesis and plant sap data

By knowing how to use photosynthesis and plant sap data for determining plant health, fast and effective solutions could be established for the optimisation of crops. This technique, which could help farmers utilise every bit of usable land effectively, is the focus of Marguerite Westcott’s PhD study. She is a junior lecturer and plant eco-physiologist in die Department of Plant Sciences at the University of the Free State.

Westcott uses this technique in her studies to prove that a newly-developed bio-stimulant stimulates plants in order to metabolise water and other nutrients better, yielding increased crops as a result.

Agricultural and mining sectors benefit from research

The greatest part of these projects focuses on the agricultural sector. Westcott and a colleague, Dr Gert Marais, are researching the physiology of pecan and citrus trees in order to optimise the growth of these crops, thus minimising disease through biological methods. Field trials are being conducted in actively-producing orchards in the Hartswater and Patensie areas in conjunction with the South African Pecan Nut Producers Association (SAPPA) amongst others.
 
The principles that Westcott applies in her research are also used in combination with the bio-stimulant in other studies on disturbed soil, such as mine-dump material, for establishing plants in areas where they would not grow normally. This is an economical way for both the agricultural and mining sectors to improve nutrient absorption, stimulate growth, and contribute to the sustainable utilisation of the soil.

Description: Pecan nut orchards  Tags: Pecan nut orchards

The bio-stimulant contributes to the immunity of the plants.
It was tested in these pecan nut orchards (Hartswater).

Soil rehabilitation key aspect in research projects

“One of two things is happening in my research projects. Either the soil is rehabilitated to bring about the optimal growth of a plant, or the plants are used to rehabilitate the soil,” says Westcott.

Data surveys for her PhD studies began in 2015. “This will be a long-term project in which seasonal data will be collected continuously. The first set of complete field data, together with pot trial data, will be completed after the current crop harvest,” says Westcott.

 

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