Celery must be free from which of the following diseases?

Celery must be free from pink rot, which is caused by the fungus Phytophthora cactorum. This disease can severely affect the quality and marketability of celery crops, leading to rotting in the stems and roots. Pink rot is particularly damaging because it can spread rapidly in wet conditions, making it important for growers to manage irrigation and handle crops carefully to prevent infection.

While other diseases such as root rot, black rot, and soft rot can also affect celery, the emphasis on pink rot is particularly relevant due to its specific implications for celery health and agricultural practices. The presence of pink rot not only decreases yield but can also lead to significant post-harvest losses, which is why it is critical to ensure that celery is free from this disease.