Select the disease triangle with three necessary components for a plant disease to occur –

Correct option is B

The correct answer is (B) Susceptible host, pathogen, favorable environment

Explanation:
• The 'Disease Triangle' is a fundamental concept in plant pathology. It represents the relationship between three factors required for a disease to develop.
• 1. Pathogen: An infectious agent (fungus, bacteria, virus, etc.) must be present and virulent.
• 2. Susceptible Host: The plant must be in a state where it can be infected by the pathogen.
• 3. Favorable Environment: Environmental conditions (temperature, humidity, soil pH) must be conducive for the pathogen to thrive and the host to be compromised.
• If any one of these three components is missing, the disease will not occur. Management of plant diseases often involves removing one of these legs of the triangle.

Information Booster:
• Modern plant pathology sometimes includes a fourth dimension: 'Time', making it a disease tetrahedron or pyramid.

Additional Knowledge:
• Option A, C, and D are incorrect because they include 'steroids' or 'symptoms'. A symptom is an effect/result of a disease, not a component required to start the disease. Steroids are organic compounds and not a basic component of the disease triangle model.