Which term describes a strain of a virus that has adapted to a specific host?

The term that describes a strain of a virus that has adapted to a specific host is "Race." In plant pathology, "race" refers to a specific variation within a pathogen species that has developed adaptations allowing it to infect certain cultivars of a host plant. This term is particularly relevant in the context of plant viruses and fungal pathogens, where different races can exhibit varying levels of virulence against different plant varieties.

Understanding the concept of "race" is crucial for managing diseases in crops because it helps in identifying and targeting specific pathogen strains that affect particular plant types. This knowledge allows for more effective breeding programs and disease management strategies, as it highlights the importance of recognizing genetic differences in both hosts and pathogens.

The other terms have different meanings in the context of plant pathology. "Type" typically refers to a classification within a species but does not inherently include the aspect of host adaptation. "Species" is a broader classification that encompasses all strains and variations of a pathogen, while "variant" usually relates to a genetic change or mutation but does not specifically indicate adaptation to a particular host. Thus, "race" is the most accurate choice for describing a virus strain tailored to a specific host.