What type of pathogens is specific to only one pest species?

The correct choice identifies pathogens that target a single pest species, indicating that they have a specialized interaction with that specific organism. These pathogens have evolved to exploit particular biological features, vulnerabilities, or behaviors of their host pest, making them highly effective in managing that specific population.

In contrast, the other types of pathogens mentioned have broader targets. Generalist pathogens can infect multiple species and are not restricted to a single pest, which gives them a wider application but may not be as efficient against one specific type of pest. Broad-spectrum pathogens also affect a range of organisms and are less specialized, which means they may not effectively control a designated pest population. Finally, multiple pest pathogens are capable of infecting several different pests rather than focusing on just one. Thus, choosing a pathogen that is specific to one pest species can be critical in targeted pest management strategies, leading to more successful outcomes.