Celery phoma rot

The causative agent of celery phoma rot is the fungus Calophoma complanata. This disease is a significant fungal infection affecting various plants within the Apiaceae family. The pathogen is highly persistent, capable of surviving in soil, crop debris, and on seeds for several seasons, posing a persistent threat to susceptible host plants.

The primary hosts of this pathogen are celery (both root and leaf varieties), parsnips, and parsley. The disease causes severe damage throughout the plant's life cycle, from early seedling stages in the field to the post-harvest storage phase, leading to significant yield losses and reduced crop marketability.

Symptoms typically manifest as brown or grayish-brown lesions on petioles and leaf blades. As the infection progresses, small black fruiting bodies called pycnidia appear in the center of these lesions. In root crops, the fungus causes a dry rot, where internal tissues turn spongy, often creating cavities filled with a grey fungal mycelium.

The development and spread of Calophoma complanata are favored by high humidity, rainfall, and moderate temperatures. The fungus spreads through wind-borne spores, splashing rain, contaminated irrigation water, and infected agricultural equipment, making it difficult to contain in wet, temperate climates.

Effective management requires an integrated approach starting with strict crop rotation, avoiding Apiaceae plants on the same field for at least 3-4 years. Using disease-free seeds is crucial, as well as the deep burial of crop residues to reduce primary inoculum. If symptoms appear, applying registered fungicides can help mitigate the impact of the disease.