Some common grapevine diseases in South Africa
Farmer's Weekly|June 30, 2023
In this article, Janine Ryan looks at the symptoms, treatment and prevention of some of South Africa's most common fungal, bacterial and viral diseases of grapevines.
Janine Ryan
Some common grapevine diseases in South Africa

Like grapes grown in any other region, South African grapes can be susceptible to certain diseases. However, it's important to note that the prevalence and severity of diseases can vary depending on factors such as climate, grape varieties grown, farming practices, and disease management strategies implemented by growers.

South Africa has a diverse climate, ranging from Mediterranean in the Western Cape to subtropical in certain regions, which can create different disease pressures. In some areas, such as the Cape Winelands, the conditions are well suited to grape cultivation, with dry summers and low humidity, which can help reduce the incidence of certain fungal diseases.

However, certain grape diseases, including downy mildew and powdery mildew, can still pose challenges, particularly in regions where cool, wet conditions prevail during the growing season. Botrytis bunch rot can be a concern in areas with higher humidity, which can promote the development and spread of the fungus.

Despite these challenges, the industry's commitment to research, innovation and best practice mitigates the risks and helps to maintain a competitive grape sector.

FUNGAL DISEASES DOWNY MILDEW

Downy mildew (Plasmopara viticola) can cause significant damage to grapevines. According to the Michigan State University: Integrated Pest Management (MSU), downy mildew is widespread. The fungus thrives in cool, humid conditions. The spores are wind-borne.

Initial symptoms include light green to yellow spots. The MSU explains that these 'oil spots', as they are called, can appear greasy in appearance. "Under humid conditions, white downy spore masses can be seen on the lower leaf surface." The MSU says that these lesions appear five to 17 days after infection, eventually turning brown as the infected tissue dies.

This story is from the {{IssueName}} edition of {{MagazineName}}.

Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 9,000+ magazines and newspapers.

This story is from the {{IssueName}} edition of {{MagazineName}}.

Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 9,000+ magazines and newspapers.

MORE STORIES FROM FARMER'S WEEKLYView all
Syngenta Seedcare celebrates a decade of innovation
Farmer's Weekly

Syngenta Seedcare celebrates a decade of innovation

Syngenta's ambition is to enable their customers' investments to grow in healthy soil from treated seeds to young plants through innovation and collaboration, writes Magda du Toit.

time-read
3 mins  |
November 22, 2024
Agri workers shine at Western Cape awards
Farmer's Weekly

Agri workers shine at Western Cape awards

Lindie-Alet van Staden, a garden and olive orchard manager at L’Ormarins Wine Estate in Franschhoek, was crowned as the Western Cape Prestige Agri-Worker of 2024 at a gala event recently held near Paarl.

time-read
1 min  |
November 22, 2024
Small and large farmers recognised at grain awards
Farmer's Weekly

Small and large farmers recognised at grain awards

The annual Grain SA/Syngenta awards ceremony bears testimony to the quality of farmers in the grain industry.

time-read
1 min  |
November 22, 2024
Growing partnerships: Fedgroup's flexible and innovative approach
Farmer's Weekly

Growing partnerships: Fedgroup's flexible and innovative approach

Janine Ryan spoke to Warren Winchester, general manager of impact investing at Fedgroup, about why the company became involved in agriculture, and what it offers farmers and their immediate communities.

time-read
6 mins  |
November 22, 2024
Why fish farms fail, and how to avoid becoming a statistic
Farmer's Weekly

Why fish farms fail, and how to avoid becoming a statistic

The popularity of launching fish farms is not matched by their success. Leslie Ter Morshuizen, owner of Aquaculture Solutions, explores the factors that cause most of these businesses to go under.

time-read
3 mins  |
November 22, 2024
Where history and modernity meet in a luxurious setting
Farmer's Weekly

Where history and modernity meet in a luxurious setting

Brian Berkman kept his eyes peeled for ghosts in the oldest continuously run hotel in South Africa, but all he found was a fabulous two-night stay.

time-read
4 mins  |
November 22, 2024
THE HITCHING POST
Farmer's Weekly

THE HITCHING POST

I'm a stylish elderly lady with a radiant glow and a good sense of humour that keeps me young at heart.

time-read
2 mins  |
November 22, 2024
Cutworms: check the weeds on your fields!
Farmer's Weekly

Cutworms: check the weeds on your fields!

Zunel van Eeden explains why understanding the ecological interplay between cutworms and weeds is crucial for effective pest management. Producers should disrupt the life cycle of cutworms to minimise crop damage.

time-read
5 mins  |
November 22, 2024
Does high-density grazing mimic grazing patterns of game?
Farmer's Weekly

Does high-density grazing mimic grazing patterns of game?

In their paper on high-density grazing in Southern Africa, professors Angelinus Franke and Elmarie Kotzé from the Department of Soil, Crop and Climate Sciences at the University of the Free State say high-density grazing systems may not accurately reflect natural ecosystems. Roelof Bezuidenhout reports.

time-read
5 mins  |
November 22, 2024
Global grain outlook: 2024/25 marketing season
Farmer's Weekly

Global grain outlook: 2024/25 marketing season

In its latest summer crops report, the Crop Estimates Committee says South African farmers intend to plant 4,47 million hectares of summer grains and oilseeds in the 2024/25 season, up 1% from the previous season. As South Africa exports maize and soya bean, Annelie Coleman reports on the latest trends in the international grain and oilseed markets, amid fluctuations in weather conditions and ongoing armed conflicts.

time-read
5 mins  |
November 22, 2024