Question:
What is the causal organism of early blight of potato ?
What is the causal organism of early blight of potato ?
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To remember potato blights:
- Early Blight = Alternaria solani (Target-board spots).
- Late Blight = Phytophthora infestans (Rapid water-soaked rotting).
- Early Blight = Alternaria solani (Target-board spots).
- Late Blight = Phytophthora infestans (Rapid water-soaked rotting).
Updated On: Jul 23, 2026
- Alternaria solani
- Phytophthora infestans
- Rhizoctonia solani
- Synchytrium endobioticum
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The Correct Option is A
Solution and Explanation
Step 1: Understanding the Concept:
Potato (Solanum tuberosum) is susceptible to several devastating fungal pathogens.
Distinguishing between these diseases requires identifying their unique symptomatic expressions and specific taxonomic causal organisms.
Step 2: Detailed Explanation:
Let us evaluate each pathogen listed in the options:
- Alternaria solani: This deuteromycete fungus is the causal agent of Early Blight of potato.
The disease is characterized by the formation of concentric, dark brown to black spots on older leaves, producing a diagnostic "target board" or "bull's eye" pattern.
- Phytophthora infestans: This oomycete is the causal organism of Late Blight of potato, which is historically famous for causing the Irish Potato Famine.
It causes water-soaked lesions on leaves that rapidly turn black under humid conditions.
- Rhizoctonia solani: This soil-borne fungus causes Black Scurf and collar rot of potato, forming black sclerotial masses on the tuber surfaces.
- Synchytrium endobioticum: An obligate biotrophic fungus that causes Potato Wart disease, resulting in cauliflower-like tumorous growths on the tubers.
Therefore, Alternaria solani is the correct causal organism for early blight.
Step 3: Final Answer:
The causal organism of early blight of potato is Alternaria solani.
Potato (Solanum tuberosum) is susceptible to several devastating fungal pathogens.
Distinguishing between these diseases requires identifying their unique symptomatic expressions and specific taxonomic causal organisms.
Step 2: Detailed Explanation:
Let us evaluate each pathogen listed in the options:
- Alternaria solani: This deuteromycete fungus is the causal agent of Early Blight of potato.
The disease is characterized by the formation of concentric, dark brown to black spots on older leaves, producing a diagnostic "target board" or "bull's eye" pattern.
- Phytophthora infestans: This oomycete is the causal organism of Late Blight of potato, which is historically famous for causing the Irish Potato Famine.
It causes water-soaked lesions on leaves that rapidly turn black under humid conditions.
- Rhizoctonia solani: This soil-borne fungus causes Black Scurf and collar rot of potato, forming black sclerotial masses on the tuber surfaces.
- Synchytrium endobioticum: An obligate biotrophic fungus that causes Potato Wart disease, resulting in cauliflower-like tumorous growths on the tubers.
Therefore, Alternaria solani is the correct causal organism for early blight.
Step 3: Final Answer:
The causal organism of early blight of potato is Alternaria solani.
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