Introduction:-
Rice blast is a very serious disease of rice which causes a heavy amount of yield loss of rice. It is particularly on the places where rice field receives a high amount of rainfall or is highly irrigated and high amounts of Nitrogen fertilizers. Several rice blast symptoms have been seen in the world resulting in the loss of about 50 - 90% of the total yield.
The pathogen:-
The pathogen which causes rice blast is a fungus called as Pyricularia oryzae and its perfect stage is Magnaporthe grisea.
Symptoms:-
Rice blast affects on the different parts of the plant body. It affects particularly on leaves, leaf collar, panicle neck node, stem nodes and sometimes internodes. In the leaves, the fungus first causes a diamond shaped white to grey or reddish brown lesions with reddish to brown borders, the lesions then enlarges and kills the entire leaf. When the fungus attacks the leaf collar, it kills the entire leaf. When it affects the stem nodes or internodes, white panicles are produced during the heading stage or the stem gets broken at the infected node. At heading, the fungus also attacks the panicle neck node which is the girdled. If the panicle neck is infected early, the grains do not fill and the panicle remains erect. If the panicle neck is infected late, the grains become partially filled, the base of panicle breaks and the panicle drops.
Control:-
Following are the control measures for this disease:
1. Planting resistant varieties.
2. Early planting
3. Keeping Nitrogen fertilizers to the minimum necessary
4. Using chemical fungicides
5. Using biocontrol microorganisms like Trichoderma sp., Pseudomonas sp., Streptomyces sp., etc. and other biocontrol means like neem extract, rye extracts, etc.
Rice blast is a very serious disease of rice which causes a heavy amount of yield loss of rice. It is particularly on the places where rice field receives a high amount of rainfall or is highly irrigated and high amounts of Nitrogen fertilizers. Several rice blast symptoms have been seen in the world resulting in the loss of about 50 - 90% of the total yield.
The pathogen:-
The pathogen which causes rice blast is a fungus called as Pyricularia oryzae and its perfect stage is Magnaporthe grisea.
Symptoms:-
Rice blast affects on the different parts of the plant body. It affects particularly on leaves, leaf collar, panicle neck node, stem nodes and sometimes internodes. In the leaves, the fungus first causes a diamond shaped white to grey or reddish brown lesions with reddish to brown borders, the lesions then enlarges and kills the entire leaf. When the fungus attacks the leaf collar, it kills the entire leaf. When it affects the stem nodes or internodes, white panicles are produced during the heading stage or the stem gets broken at the infected node. At heading, the fungus also attacks the panicle neck node which is the girdled. If the panicle neck is infected early, the grains do not fill and the panicle remains erect. If the panicle neck is infected late, the grains become partially filled, the base of panicle breaks and the panicle drops.
Control:-
Following are the control measures for this disease:
1. Planting resistant varieties.
2. Early planting
3. Keeping Nitrogen fertilizers to the minimum necessary
4. Using chemical fungicides
5. Using biocontrol microorganisms like Trichoderma sp., Pseudomonas sp., Streptomyces sp., etc. and other biocontrol means like neem extract, rye extracts, etc.
Tags
Plant Pathology