In the June 2026 issue of Oilseeds Focus we take a look at some of the key agronomic challenges and opportunities facing oilseed producers. This includes the use of fungicides to manage blackleg in canola, strategies to limit nematode losses, and the role of quality seed treatments in modern agriculture. This issue also takes a closer look at the science of crop photosynthesis and unpacks how crop rotation systems can influence weed pressure and herbicide use under conservation agriculture practices. Together, these articles provide practical insight into improving productivity, resilience, and the long-term sustainability of oilseed production systems.
The use of fungicides to manage blackleg of canola
Canola has become an important crop in the Western Cape over the last two decades. The area planted to canola is increasing year to year, and projections indicate further increases in the coming years. Blackleg disease is the most important disease of canola globally, with losses estimated at 10 to 20% in major canola-producing regions such as Australia, Canada and the United Kingdom, and severe epidemics can cause complete crop failure. To limit the impact of this disease locally and to prevent severe epidemics in the future, it is important to study the disease and its pathogens under local conditions. Read more in this issue of Oilseeds Focus.
Battling nematodes in oilseed crops
Producers face an ongoing challenge from plant-parasitic nematodes. Although several species are found in South Africa, only a few cause significant economic damage. Chief among these is the root-knot nematode (Meloidogyne spp.), known for its wide host range and devastating impact across multiple crops. The goal is not to eradicate nematodes but to keep populations below damaging thresholds. Their wide host range and ability to survive and damage other rotation crops, make management complex.
Importance of quality seed treatments
A crop’s success is often determined long before it emerges from the soil. The first few days after planting are among the most vulnerable stages in a plant’s life cycle, when seeds are exposed to soil-borne pathogens, pests, and environmental stressors. Without effective protection, poor establishment, uneven emergence, and reduced plant vigour can limit yield potential before the crop has an opportunity to develop fully. This is where seed treatments play a vital role. In modern agriculture, they offer a highly effective and targeted approach to protecting and maximising crop performance from the start of the season.
Reaping the sun’s energy: Optimising crop photosynthesis
A positive approach to crop production is supported by factors that enhance the crop’s photosynthetic capacity. This may seem obvious, yet there have been many disappointments with approaches aimed at increasing yield components, which ultimately depend on available energy to produce food. To achieve effective and sustainable increases in yield, photosynthesis must be increased. This requires that every input or practice in crop production be interrogated with respect to its effect on the crop’s ability to photosynthesise.
Crop rotation for managing weed populations
Managing weeds is a full-time job, as there are many factors to consider. Most Western Cape producers follow the three principles of conservation agriculture: minimum soil disturbance, >30% soil cover, and crop rotation – all of which influence weed management. What is the reality for those producers? Does adopting conservation agriculture practices lead to the same reduction in herbicide use, or are concerns about ongoing reliance justified? To answer this question, long-term crop rotation trial data from Langgewens Research Farm was used to determine which factors influence whether to spray a herbicide or not.
The June 2026 issue of Oilseeds Focus can be downloaded as an interactive flipbook at https://digimags.agriorbit.com/books/Oilseeds-focus-June-2026/ or download the PDF version here. To subscribe, phone Beauty Mthombeni on 064 890 6941 or SMS ‘Subscribe’ and your phone number to 064 890 6941 and we will get back to you.
