Root-knot and lesion nematodes (Meloidogyne and Pratylenchus spp respectively) are the most important nematodes faced by grain farmers in South Africa. Increases in soil temperature and the presence of moisture lead to a resumption of activity after winter dormancy. This is especially the case at present, following the abundant rain in most local crop production areas in summer.
In their infective stages, these microscopic organisms use their reserve energy to move through the soil by means of the water layers surrounding soil particles in search for the roots of possible hosts. They infect and feed on the roots of grains and weeds, and can cause serious crop damage.
Weeds should therefore be removed from grain lands to prevent infestation, as nematodes can survive in their roots. Live root-knot nematode females have been found in the middle of winter in the Free State on ragwort bushes. These abundant, yellow-flowered weeds create the ideal habitat for the nematodes, which start reproducing as soon as the soil temperature rises.
RAPID REPRODUCTION
Two of the most prevalent rootknot nematodes in South Africa, M. incognita and M. javanica, can develop at fairly low base temperatures of 9,8°C and 10,6°C respectively.
A single female root-knot nematode can produce up to 1 800 eggs (reported in a susceptible soya bean cultivar) within 20 to 30 days of infecting the root of a host plant at a soil temperature of 26°C. This means that a single female, which can live for an average of three months, has the potential to produce approximately 5 400 eggs in one season.
Should the soil temperature increase, however, the nematode could reproduce within a shorter time, which is why farmers should keep their grain lands free of weeds.
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.
Already a subscriber ? Sign In
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.
Already a subscriber? Sign In
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
