Black spot of roses is caused by which management approach?

• A. The primary host of a Colorado Blue Spruce.
• B. Managing planting in the correct locations and selecting resistant varieties.
• C. Caused by soil borne fungal pathogens called "water molds".
• D. Insects that feed on rose leaves.

Answer: (B)

Managing where you plant and using resistant rose varieties is the most effective way to prevent black spot. This disease thrives in damp, crowded situations with poor air movement, so placing roses where they get good airflow and sun helps leaves dry quickly and reduces the window for fungal infection. Choosing varieties bred for resistance lowers the number of susceptible leaves, which further cuts down disease pressure. The other options introduce unrelated hosts or organisms, or focus on pests rather than a fungal disease that affects leaves, so they don’t address the preventive steps that truly minimize black spot risk.