Discoloration in the vascular tissue (water conduction tissue) is a symptom of what kind of disease:

• A. Root rot
• B. Leaf spot
• C. Wilt
• D. Rust

Answer: (C)

Discoloration in the vascular tissue points to a problem with the plant’s water-conducting system (the xylem). When a wilt-causing pathogen colonizes or blocks the xylem vessels, the water transport is impeded, and the tissue inside these vessels browns or darkens. That blockage means water can’t move effectively from roots to leaves, so the plant wilts even if the soil isn’t dry. This vascular discoloration is a hallmark of wilt diseases, such as Fusarium or Verticillium wilts.

Leaf spot shows surface lesions on leaves, rust presents as pustules or powdery spots on surfaces, and root rot primarily damages the roots themselves, often leading to overall plant decline without the distinctive internal vascular browning.