Botrytis bunch rot, also known as gray mold, is a common fungal disease that affects grapes. It can cause significant damage to grape clusters, leading to decreased yield and quality of the fruit. Here are the symptoms of Botrytis bunch rot that you should look out for in grapes:
- Grayish-Brown Mold: One of the most noticeable signs of Botrytis bunch rot is the development of a grayish-brown mold on the grape clusters. This mold usually starts on the berries and may spread to the stems and pedicels. It gives the affected grapes a fuzzy or velvety appearance.
- Shriveling and Wrinkling: Infected grapes tend to shrivel and become wrinkled. They may become soft and mushy as the disease progresses. The affected berries lose their plumpness and become dehydrated.
- Loss of Berry Integrity: The fungal infection causes the grape berries to lose their integrity. They may become more fragile and prone to splitting or rupturing. This can lead to further decay and make the cluster susceptible to other pathogens.
- Bitter Rotten Smell: As the rot progresses, an unpleasant odor, often described as a bitter rotten smell, may become noticeable. This smell is a result of the metabolic byproducts produced by the fungus.
- Spore Production: Botrytis bunch rot is characterized by the production of abundant spores. These spores can be seen as a grayish dust or powdery substance on the surface of infected grapes.
- Cluster Collapse: In severe cases, the entire grape cluster may collapse due to the decay caused by Botrytis bunch rot. The berries may become completely desiccated, turning into raisins, and the cluster may become a mass of shriveled, moldy matter.
It’s important to note that the symptoms mentioned above can also be caused by other diseases or environmental factors. Therefore, proper diagnosis by a knowledgeable expert or agricultural professional is essential for accurate identification of Botrytis bunch rot. Early detection and appropriate management practices can help minimize the impact of this disease on grape crops.
