How do abiotic factors influence plant diseases?

Abiotic factors play a significant role in influencing plant diseases primarily through physical and chemical changes that affect the plants themselves. These factors include temperature, humidity, soil pH, and environmental stress such as drought or flooding. For instance, high humidity levels can promote the growth of fungal pathogens, while extreme temperatures can weaken plant defenses, making them more susceptible to infections. Chemical changes in soils, such as nutrient deficiencies or toxicities, can also lead to weakened plants that are more prone to disease. Therefore, the correct understanding is that abiotic factors affect plants directly, creating conditions that may either promote or inhibit the development and severity of plant diseases.

Other choices do not accurately address the core influence of abiotic factors. While some may relate to pest populations or competition for resources, they do not capture the direct impact of abiotic stressors on the plant's susceptibility to pathogens.