Powdery mildew can be reduced by which action?

• A. Pruning trees and shrubs to increase sunlight
• B. Fertilizing with nitrogen
• C. Increasing watering
• D. Mowing low

Answer: (A)

Powdery mildew flourishes in shaded, stagnant, humid microclimates on the foliage. By pruning to let more sunlight reach the leaves, you increase air flow and dry the leaf surfaces after dew or rain, making the environment less favorable for the fungus to germinate and spread. The fungi rely on still, humid conditions, so improving sun exposure and airflow is the most effective way to reduce this disease.

Fertilizing with nitrogen often promotes lush, soft growth that powdery mildew can exploit, increasing susceptibility. Increasing watering raises surface humidity and favors the pathogen, and mowing low doesn’t address the canopy conditions where powdery mildew typically develops.