Wilt diseases are caused by
Show Hint
Bacteria use slime (EPS) and Fungi use their own bodies (hyphae) to clog the vessels.
- Heat
- Drought
- Bacteria and Fungi
- Viroids
The Correct Option is C
Solution and Explanation
The question asks for the primary biotic causes of systemic "wilt" symptoms in plants. Wilting is the loss of turgor pressure due to the blockage of water transport in the xylem.
Step 2: Detailed Explanation:
• Fungi (C): Many soil-borne fungi, notably species of Fusarium (e.g., F. oxysporum) and Verticillium, invade the vascular system. They produce mycelia and spores that physically block the xylem vessels, leading to fungal wilt.
• Bacteria (C): Pathogens like Ralstonia solanacearum produce massive amounts of extracellular polysaccharides (EPS) in the xylem. This "slime" creates a highly viscous environment that prevents water from reaching the upper parts of the plant, causing bacterial wilt.
• Abiotic factors (A & B): While heat and drought cause "physiological wilting," true "wilt diseases" as defined in plant pathology refer to the infection and colonization of vascular tissues by pathogens.
Final Answer:
Wilt diseases are classically caused by specific vascular-invading bacteria and fungi.
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