Which of the following describes powdery mildew?

• A. Fungal growth that appears as dark spots
• B. Cottony white fungal growth on leaves
• C. Brown lesions with yellow margins
• D. Orange pustules on stems

Answer: (B)

Powdery mildew is a well-known fungal disease that is characterized by its distinctive appearance, which often resembles a fine, white powder or dust on the surfaces of plant leaves. This is typically most prominent on the upper sides of leaves but can also affect stems and flower buds. The white, cottony appearance is a key indicator of powdery mildew, which distinguishes it from other types of fungal infections that may manifest as different color spots or lesions.

The other descriptions in the options paint a picture of various other types of fungal infections or plant diseases. Dark spots typically signify different types of fungal infections or diseases, while brown lesions with yellow margins can represent issues such as bacterial leaf spot or other forms of rot. Orange pustules are commonly associated with rust diseases, which have a different growth form and structure compared to powdery mildew. Understanding the specific characteristics of each fungal infection is crucial for diagnosing plant disease accurately and implementing effective management practices.