Wheat blast disease was first seen in Brazil in 1985 and later spread to Brazil, Bolivia, Paraguay, and Argentina in South America. At various times about 3 million hectares of wheat land are affected by blasts and the yield is reduced at a significant rate. Variations in disease severity and output are observed depending on the wheat variety and sowing time. Due to this disease, the yield of affected wheat is reduced by 25 to 30 %, and the crops of some fields are almost entirely destroyed.
What Are Causes of Wheat Blast Disease?
Wheat blast is a harmful fungal disease. The scientific name of the fungus is Magnaporthe oryzae pathotype Triticum (Pyricularia oryzae). Transmission of this disease can occur if there is relatively warm and humid weather at the time of wheat seed emergence and flowering.
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What Are The Symptoms of The Disease?
- In the early stages of wheat fields affected by blasts, the grain turns white in some places, and in favorable weather, it spreads quickly throughout the field.
- Some grains of wheat have a whitish surface that is easily distinguishable from the green and healthy portion below; Almost the entire part of some seeds dries up and turns white. This is a typical symptom of the disease.
- Mainly wheat grain is attacked by the fungus. Black spots appear on the affected area of the seed and the upper part of the affected area turns white. However, if the base of the seed is attacked, the entire seed dries up and turns white.
- Infected pods are malnourished and shriveled and the pods turn gray. The leaves can also be attacked by blast disease and in this case, small gray necrotic spots like eyes appear on the leaves.
How Does it Spread?
The disease spreads through infected seeds and wind. Infection occurs when wheat grains remain wet for 12 to 24 hours due to rain, with the temperature being 18°C or higher.
The disease germs spread rapidly through the air. The pathogen of blast disease can survive in some grasses, such as alternative host weeds.
However, the clear symptoms of the disease are not easily visible. Under favorable conditions, alternate host weeds can cause epidemics of blast disease.
How To Control And Manage Wheat Blast Disease?
- Go and get wheat seeds from the fields that didn’t get Attacked by the blasts.
- Cultivate relatively less sensitive varieties.
- Sow the seeds at the right time to avoid rain and high temperatures during germination.
- Before sowing, seeds should be treated with Provax 200 FF at the rate of 3 g per kg of seed or Vitaflo 200 FF at the rate of 3 ml. Seed treatment will also suppress other seed-borne diseases of wheat and increase yield.
- You should keep wheat fields and land boundaries free from weeds.
- As a preventive measure, a fungicide should be sprayed once at the time of emergence and again after 12 to 15 days. 6 grams of Nativo 75WG -Novita 75 WG in 10 liters of water should be sprayed well for every 5 % of the land. Spraying will control wheat leaf blight, seed black spots, and rust.
- When using fungicides, wear gloves and face masks to avoid contact and inhalation of chemicals.
I am Gaushoul Agam,
𝐂𝐨-𝐅𝐨𝐮𝐧𝐝𝐞𝐫 & 𝐂𝐄𝐎,
As an experienced SA Horticulture Officer in the Horticulture Wing of the Department of Agricultural Extension, Ministry of Agriculture, Government of the People’s Republic of Bangladesh, I am dedicated to advancing agriculture and farming.
With a mission to address global food safety challenges amid a growing population, diminishing arable land, and the impacts of climate change on agriculture, I founded ToAgriculture. Through this platform, I empower readers with modern agricultural techniques, effective pest and disease control, and sustainable agricultural management, leading to a more secure and prosperous future in agriculture.
With over four years of expertise in field crops and seven years in horticulture crops, my knowledge spans fruit and vegetable farming techniques, adept pest-disease management, proficient irrigation strategies, and the art of grafting. Join me on this journey of discovery as I share insights and experiences to guide readers toward a sustainable future.