Which of the following is a characteristic of non-infectious plant diseases?

Non-infectious plant diseases are primarily characterized by being caused by environmental factors rather than pathogens like bacteria, fungi, or viruses. These environmental influences could include extremes in temperature, inadequate nutrients, toxicity from chemicals, or unfavorable soil conditions. Since they arise from abiotic factors rather than biological agents, these diseases do not result from an infectious process and cannot be spread from plant to plant in the same way that infectious diseases can. This distinction is important in plant pathology as it informs management practices; non-infectious diseases often require changes in agricultural practices, environmental conditions, or soil amendments rather than the application of fungicides or pesticides.

The other options center around infectious diseases that involve pathogens and can spread through direct contact or systemic infection, which is not applicable to non-infectious diseases. Understanding that non-infectious diseases originate from non-living factors helps in identifying and remedying plant health issues effectively.