Q.53. ‘Bakanae’ disease or ‘foolish seedling’ disease is caused by
(A) Fungus
(B) Bacterium
(C) Virus
(D) Mycoplasma

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Bakanae disease, also known as “foolish seedling” disease, affects rice plants worldwide, causing abnormal elongation and weakening. If you’re preparing for exams like NEET, ICAR, or agriculture entrances, understanding Bakanae disease caused by which pathogen is crucial. This article breaks down the MCQ options with scientific explanations, symptoms, and prevention tips.

The Correct Answer: (A) Fungus

Bakanae disease caused by the fungus Gibberella fujikuroi (teleomorph of Fusarium fujikuroi), an ascomycete pathogen. It produces gibberellins—plant hormones that trigger excessive stem growth, making seedlings “foolish” or bakanae (Japanese for “foolish”).

Infected rice plants show:

• Elongated, pale green stems.

• Reduced tillering and sterility.

• Up to 20-90% yield loss in severe cases.

The fungus spreads via contaminated seeds or soil. Historical outbreaks in Japan (1890s) led to its discovery, linking it to rice bakanae.

Why Not Bacterium? Option (B) Explained

Bacteria like Xanthomonas oryzae cause bacterial leaf blight in rice, but Bakanae disease caused by bacterium is incorrect. Bacterial infections typically show water-soaked lesions or wilting, not hormone-induced elongation. No bacterial species produces gibberellins mimicking Bakanae symptoms.

Virus Ruled Out: Option (C) Analysis

Viruses, such as Rice tungro virus, cause stunting or mosaic symptoms in rice via insect vectors. However, Bakanae disease caused by virus doesn’t fit—viral infections lack the specific “foolish” elongation from fungal toxins. Electron microscopy and Koch’s postulates confirm no viral etiology for Bakanae.

Mycoplasma Incorrect: Option (D) Details

Mycoplasmas (phytoplasmas) cause little leaf or witches’ broom diseases with yellowing and proliferation, transmitted by leafhoppers. Bakanae disease caused by mycoplasma is wrong; these wall-less bacteria don’t produce gibberellins or match soil/seed transmission of Fusarium.

Prevention and Management Tips

Control Bakanae disease caused by fungus through:

• Seed treatment with carbendazim or tricyclazole.

• Resistant rice varieties like IR36.

• Crop rotation and soil solarization.

This knowledge is vital for agronomy students and farmers in rice-growing regions like India.