Which type coats leaves and stems and prevents fungal pathogens from establishing themselves on the plant?

• A. Powdery mildew
• B. Protectant fungicides
• C. Systemic fungicides
• D. Fairy rings

Answer: (B)

Protectant fungicides act as a protective film on leaf and stem surfaces, forming a barrier that stops fungal spores from germinating or penetrating the plant tissue. They must be present on the plant before infection, and they usually stay on the surface rather than moving inside the plant, so they’re preventive rather than curative. Because they sit on the surface, rain or irrigation can wash them off, necessitating reapplication to maintain protection.

Powdery mildew describes a disease by the white powdery growth it causes, not a type of coating. Systemic fungicides, by contrast, are absorbed and moved within the plant to inhibit pathogens, rather than forming a surface film. Fairy rings are a turf disease symptom caused by soil-dwelling fungi, not a protective coating on leaves and stems.