Which type of fungicide is likely not effective against a wide range of pathogens?

A narrow spectrum fungicide is specifically designed to target a limited range of pathogens. This is often due to its mode of action, which may be highly effective against particular types of fungi but not against others. Such targeted approaches can be beneficial in certain integrated pest management strategies, where the goal is to control specific diseases while minimizing impact on non-target organisms or beneficial microbes.

In contrast, broad-spectrum fungicides are formulated to affect a wider variety of fungal pathogens, making them more versatile for treating various diseases. Systemic fungicides are absorbed by the plant and act throughout its tissues, providing control over pathogens that may be located within the plant, while contact fungicides act on the surface of the plant and are typically effective against pathogens that come into direct contact with the chemical.

This focus on a specific subset of targets is what limits the effectiveness of narrow spectrum fungicides against a broader array of fungal diseases.