Name a common disease that affects landscape plants.

Powdery mildew is a widely recognized fungal disease that affects a variety of landscape plants. It is characterized by white, powdery spots that appear on the leaves, stems, and buds. The disease typically thrives in warm, dry conditions, affecting plants by inhibiting photosynthesis and leading to premature leaf drop, which can result in reduced vigor and aesthetic quality.

Identifying powdery mildew is essential for landscape maintenance, as it can spread rapidly from one plant to another. Effective management includes cultural practices such as proper plant spacing for air circulation, avoiding overhead irrigation to minimize humidity, and utilizing resistant plant varieties where possible.

In the context of the other options, while they are all known to affect landscape plants, powdery mildew is particularly common and significant in many garden settings, making it a key disease for landscape professionals to recognize and manage.