What is defined as a "pathogen"?

A pathogen is defined as a disease-causing organism, which encompasses various types of microorganisms, including bacteria, fungi, viruses, and nematodes that can lead to disease in plants and animals. Pathogens are of particular concern in the context of turfgrass management as they can severely impact plant health, leading to symptoms such as discoloration, wilting, and even death of the grass. Understanding what constitutes a pathogen is fundamental for effective pest management, as identifying the specific pathogen responsible for turf issues allows for the implementation of targeted management practices to mitigate its effects. In contrast, the other options refer to organisms that do not primarily contribute to disease development, either promoting soil health or benefiting the plant in some way.