What is the term for the source of a plant pathogen that causes a disease?

The term that describes the source of a plant pathogen responsible for causing a disease is "inoculum." This refers to the pathogen's reproductive structure or material that introduces the pathogen to a host plant, potentially leading to infection. Inoculum can take various forms, such as spores, bacterial cells, or other infectious agents, depending on the type of pathogen involved.

Vectors are organisms that transmit pathogens from one host to another but are not the source themselves. Hosts are the plants that become infected by the pathogens and show symptoms of the disease. Symptoms are the visible effects that occur in the plant as a result of the disease, representing the physiological response of the host to the pathogen. Understanding these terms is crucial for identifying disease sources and managing plant health effectively.