Which organisms cause biotic plant diseases?

Which organisms cause biotic plant diseases?

• A. Fungi, bacteria, nematodes, viruses, parasitic plants.
• B. Abiotic factors only.
• C. Beneficial insects.
• D. Soil salinity.

Answer: (A)

Biotic plant diseases are caused by living organisms that infect and harm plants. The group listed—fungi, bacteria, nematodes, viruses, and parasitic plants—includes common living agents that invade plant tissues, multiply, and disrupt normal growth and function. For example, fungi can cause rots or blights, bacteria can lead to wilts or spots, nematodes attack roots, viruses alter growth patterns and leaf appearance, and parasitic plants attach to hosts to siphon nutrients. These are all living pathogens that produce disease. The other options involve nonliving factors or organisms that don’t cause disease themselves. Abiotic factors are environmental stresses like drought, salinity, extreme temperatures, or chemical injury that injure plants but aren’t pathogens. Beneficial insects help plants by pollinating or preying on pests, not by causing plant diseases. Soil salinity is a nonliving stressor that stresses plants rather than acting as a pathogen.

Biotic plant diseases are caused by living organisms that infect and harm plants. The group listed—fungi, bacteria, nematodes, viruses, and parasitic plants—includes common living agents that invade plant tissues, multiply, and disrupt normal growth and function. For example, fungi can cause rots or blights, bacteria can lead to wilts or spots, nematodes attack roots, viruses alter growth patterns and leaf appearance, and parasitic plants attach to hosts to siphon nutrients. These are all living pathogens that produce disease.

The other options involve nonliving factors or organisms that don’t cause disease themselves. Abiotic factors are environmental stresses like drought, salinity, extreme temperatures, or chemical injury that injure plants but aren’t pathogens. Beneficial insects help plants by pollinating or preying on pests, not by causing plant diseases. Soil salinity is a nonliving stressor that stresses plants rather than acting as a pathogen.