Which phrase lists the three factors required for disease development?

Which phrase lists the three factors required for disease development?

• A. Host resistance, pathogenicity, climate
• B. Susceptible host, pathogen, favorable environment
• C. Pest presence, soil moisture, nutrients
• D. Pollinators, weeds, sunlight

Answer: (B)

Plants get disease when three things come together: a plant that can be infected (a susceptible host), a disease-causing organism (a pathogen), and environment conditions that support the pathogen’s activity (a favorable environment). This is the disease triangle in action. If any one of these is missing or unfriendly, disease development is unlikely. A susceptible host means the plant lacks adequate resistance or tolerance to the pathogen, so infection can occur. The pathogen must be present and capable of causing disease. The environment needs to support the pathogen’s life cycle—adequate moisture, appropriate temperature, and other conditions that enable infection and spread. The phrase that lists a susceptible host, a pathogen, and a favorable environment best reflects this trio. The other choices mix in concepts not central to the disease triangle—climate, pathogenicity, pest presence, soil nutrients, or unrelated factors—so they don’t capture all three essential components.

Plants get disease when three things come together: a plant that can be infected (a susceptible host), a disease-causing organism (a pathogen), and environment conditions that support the pathogen’s activity (a favorable environment). This is the disease triangle in action. If any one of these is missing or unfriendly, disease development is unlikely.

A susceptible host means the plant lacks adequate resistance or tolerance to the pathogen, so infection can occur. The pathogen must be present and capable of causing disease. The environment needs to support the pathogen’s life cycle—adequate moisture, appropriate temperature, and other conditions that enable infection and spread.

The phrase that lists a susceptible host, a pathogen, and a favorable environment best reflects this trio. The other choices mix in concepts not central to the disease triangle—climate, pathogenicity, pest presence, soil nutrients, or unrelated factors—so they don’t capture all three essential components.