Licorice rot

Licorice rot, caused by the fungus Mycocentrospora acerina, is a significant fungal disease impacting various vegetable crops, most notably celery. The disease manifests as decay in the stalks and roots, which can lead to severe losses both in the field and during post-harvest storage.

The causal agent is a soil-borne pathogen that persists in plant debris and soil for extended periods. It infects the host tissue, causing dark, water-soaked lesions that eventually enlarge and coalesce. In celery, this rot often exhibits a distinct discoloration and softening of the crown and petiole bases.

Favorable conditions for the disease development include cool, damp weather and high relative humidity. Water splash is a primary vector for spores, spreading the fungus from the soil to the lower leaves and crowns of the plants. Poor air circulation in greenhouses can exacerbate the spread of the infection rapidly.

The economic impact of Licorice rot is substantial, as it renders the vegetable crop unmarketable. The pathogen can remain latent in tissue and develop into a rapid rot during storage, leading to complete destruction of infected produce. Consistent monitoring of storage conditions is crucial to prevent secondary spread among healthy roots.

Effective management requires an integrated approach. Recommended practices include:

• Implementing long crop rotations to reduce soil-borne inoculum.
• Ensuring proper soil drainage and ventilation to reduce ambient humidity.
• Strict sanitation measures to remove infested crop residues from fields.
• Using pathogen-free seeds and transplants to avoid initial contamination.