NORTHERN CORN LEAF BLIGHT
Northern corn leaf blight is one of the most common diseases of maize in South Africa, and while yield losses are typically minimal, they can become significant if the planted cultivar is susceptible.
The disease is caused by the fungus Exserohilum turcicum, and generally occurs before silking. It prefers moderate temperatures (around 18°C to 27°C) with prolonged periods of moisture. The fungus overwinters on maize leaf debris.
The University of Minnesota Extension (UME) says that the disease is usually more severe when infection occurs earlier.
FAST FACTS
Maize streak disease can cause stunting of maize plants and misshapen cobs.
Northern corn leaf blight can result in significant yield losses.
Grey leaf spot thrives in areas with warm temperatures and prolonged periods of high humidity (greater than 95%).
SIGNS AND SYMPTOMS
The UME says that typical symptoms of northern corn leaf blight are canoe-shaped lesions that range from 2,5cm to 15cm in length.
Initially, these lesions may be bordered by grey-green margins, which eventually turn tan colour and may contain dark areas of fungal sporulation.
The length or size of lesions may vary with different [maize] hybrids, the UME explains. Lesions generally begin on the lower leaves, before spreading to the upper leaves. Symptoms can progress rapidly, resulting in blighted leaves.
ESSENTIAL FACTS
• Pathogen: Exserohilum turcicum
• Typical signs and symptoms: canoe-shaped lesions, which are initially bordered by grey-green margins.
• Preferred conditions: moderate temperatures and high levels of humidity.
• Effects: yield losses.
Bu hikaye Farmer's Weekly dergisinin Farmer's Weekly 3 February 2023 sayısından alınmıştır.
Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 9,000+ magazines and newspapers.
Already a subscriber ? Giriş Yap
Bu hikaye Farmer's Weekly dergisinin Farmer's Weekly 3 February 2023 sayısından alınmıştır.
Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 9,000+ magazines and newspapers.
Already a subscriber? Giriş Yap
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.
