Powdery mildew can be an issue when days are warm and cooler nights with dew formation on leaves. The symptoms include white powdery patches on top section of the leaves which can cover the entire leaf under severe infection.

Fungal causal agent: Microsphaera alni (M. penicillata); Phyllactinia corylea (P. guttata)

POWDERY MILDEW

Magnolia diseases