Cultural management to reduce powdery mildew includes which practice?

• A. Selective pruning and increased air movement around branches to reduce humidity
• B. Overhead irrigation to wash spores off
• C. Increasing leaf surface moisture
• D. Planting in dense canopies

Answer: (A)

Powdery mildew tends to take hold when the plant canopy is humid and airs are slow, so creating better air circulation and a drier microclimate around the leaves is a primary cultural strategy. Selective pruning opens up the canopy, allowing more wind to move through and reducing the relative humidity on the leaf surfaces. That less humid, more ventilated environment makes it harder for the mildew to germinate and spread, which is why this practice is considered the best option for reducing powdery mildew.

Using overhead irrigation keeps foliage wet and can sustain conditions that promote fungal growth or help spores move around the plant, so it’s not a favorable approach for controlling this disease. In general, increasing leaf moisture and planting into dense canopies both create a warmer, damper microclimate that powdery mildew loves, so they’re not appropriate strategies.