Question

Which of the following disease in sugarcane is caused by Colletotrichum falcatum

• A. Smut
• B. Wilt
• C. Grassy shoot
• D. Red rot

Hint:

The most definitive field diagnostic symptom of ______Red rot______ is the presence of ______transverse white bands or patches______ crossing the red-discolored internal tissues of the sugarcane stem, accompanied by an alcoholic smell when the stalk is split open.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Sugarcane is susceptible to various fungal, bacterial, viral, and phytoplasmal diseases that can cause severe reductions in cane yield and juice quality.
Identifying the causal pathogen is crucial for executing appropriate plant pathology control measures.

Step 2: Detailed Explanation:
Let us match the diseases with their respective pathogens:
1. Red rot: This is the most destructive disease of sugarcane, often termed the "cancer of sugarcane". It is caused by the fungus Colletotrichum falcatum (perfect stage: Glomerella tucumanensis). It causes internal reddening of the pith with characteristic white transverse bands and a distinct acidic, alcoholic odor.
2. Smut: This disease is caused by the fungus Sporisorium scitamineum (formerly Ustilago scitaminea), characterized by a black whip-like structure arising from the apex of the affected stalk.
3. Wilt: This is caused by the fungus Fusarium sacchari, leading to gradual drying, hollow stems, and root degradation.
4. Grassy shoot: This is caused by a phytoplasma (Candidatus Phytoplasma) transmitted by aphids, resulting in profuse, thin, chlorotic tillering that resembles grass.

Step 3: Final Answer:
The disease in sugarcane caused by Colletotrichum falcatum is Red rot, which corresponds to option (D).