Ceratocystis paradoxa

Ceratocystis paradoxa is an ascomycete fungus belonging to the Ceratocystidaceae family. It is a significant phytopathogen that primarily affects tropical and subtropical plants. It is well-recognized for its asexual stage, formerly classified as Thielaviopsis paradoxa, which is highly efficient at colonizing host tissues under specific environmental conditions.

The pathogen is responsible for various severe plant diseases, most notably the black rot of pineapple, stem rot in sugarcane, and fruit rots in cocoa, coconut, and oil palm trees. It acts as both a field pathogen, causing damping-off or stem rot in seedlings, and a post-harvest pathogen that leads to rapid spoilage of fruits and commodities during storage and transit.

The biological cycle of this fungus involves the production of endoconidia and thick-walled chlamydospores, which enable the pathogen to survive in soil and organic debris for extended periods. Dissemination typically occurs through wind-blown spores, splashing water, infested tools, and insect vectors that transmit the fungus to wounds or fresh injury sites on the host plant.

Development of Ceratocystis paradoxa is favored by warm temperatures, typically ranging from 25°C to 30°C, combined with high relative humidity. The fungus enters the plant tissues through mechanical injuries, growth cracks, or harvesting wounds. Once inside, it secretes enzymes that decompose plant tissue, leading to rapid decay and the development of the characteristic dark, blackened appearance.

Effective management and control strategies focus on sanitation and preventative cultural practices:

• Implementing strict harvesting protocols to minimize cuts, bruises, and mechanical damage to fruits.
• Utilizing disease-resistant or tolerant crop varieties whenever available.
• Disinfecting harvesting equipment and packinghouse surfaces to reduce inoculum levels.
• Employing temperature management (cooling) to suppress fungal growth during storage and shipping.
• Removing and destroying infected plant material promptly to limit the spread of spores in the field.