Which symptom is indicative of grape powdery mildew?

The presence of white powdery masses on fruit is a classic symptom associated with grape powdery mildew, a fungal disease caused by Erysiphe necator. This symptom is particularly distinctive and is often one of the first visible signs of an infestation. The powdery appearance is caused by the growth of the fungal hyphae on the surface of the fruit, which can also spread to other parts of the plant, including leaves and stems, if left unchecked.

Recognizing this symptom is crucial for effective management of the disease, as early identification can lead to timely interventions and treatments. Grapes affected by powdery mildew may also experience secondary issues, such as reduced fruit quality and yield if the disease progresses. Other symptoms, such as yellowing of leaves, black spots on canes, or brown leaf edges, may be indicative of different issues or diseases. Understanding the specific symptoms associated with grape powdery mildew can help in better diagnosis and control measures for grape growers.