Question

The fungus causing heart rot disease in sal ,khair and teak is :

• A. Fusarium spp.
• B. Fomes spp.
• C. Ganoderma lucidum
• D. Polyporus shoreae

Hint:

Since heart rot fungi primarily enter through physical wounds, silvicultural practices should aim to minimize mechanical injuries to standing trees during logging, thinning, and pruning operations.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Heart rot is a fungal disease that decays the central, non-functional heartwood of living trees.
This rot weakens the structural integrity of the tree and reduces its value for timber, while the living outer sapwood remains largely unaffected.

Step 2: Detailed Explanation:
Let us review the common pathogens and host dynamics:
- Heart rot is primarily caused by wood-decaying basidiomycete fungi, particularly species belonging to the genus Fomes (such as Fomes caryophylli or Fomes badis, often classified under Phellinus).
These fungi enter the tree through physical wounds, broken branches, or logging scars.
Once inside, they secrete enzymes that break down lignin and cellulose in the heartwood, leaving the core of the trunk hollow or spongy.
This disease commonly affects valuable hardwood species like Sal (Shorea robusta), Khair (Acacia catechu), and Teak (Tectona grandis).
Let us review the other options:
- Fusarium species are soil-borne fungi that typically cause vascular wilting, root rot, or damping-off in young seedlings.
- Ganoderma lucidum is a root rot pathogen that attacks the base and roots of trees, causing root decay and eventual windthrow.
- Polyporus shoreae is a specific root-rot fungus of Sal that causes wet root rot, rather than generalized heart rot across Sal, Khair, and Teak.

Step 3: Final Answer:
The major fungus causing heart rot in these hardwood species is Fomes spp., corresponding to option (B).