Which statement about plant infectious diseases is true?

• A. They are caused by living pathogens.
• B. They are caused by abiotic factors.
• C. They cannot be prevented.
• D. They always kill the plant immediately.

Answer: (B)

Infectious plant diseases are caused by living pathogens such as fungi, bacteria, viruses, and nematodes that invade plant tissues and can spread from one plant to another. Abiotic factors are nonliving influences like drought, nutrient deficiencies, chemical injury, or salinity, which can cause symptoms that look like disease but aren’t infectious and don’t spread between plants. Because infectious diseases come from living organisms, they are the type of problem that can be prevented or managed through practices like sanitation, using disease-free or resistant varieties, crop rotation, proper irrigation, avoiding wounds, and controlling vectors. The statements claiming they’re caused by abiotic factors, that they cannot be prevented, or that they always kill the plant immediately do not fit the true nature of infectious diseases.