Botryodiplodia rhodina

Systematic position and nature: Botryodiplodia rhodina (often identified as Lasiodiplodia theobromae) is a notorious fungal pathogen classified within the order Sphaeropsidales. It is widely recognized as a facultative parasite that thrives in tropical and subtropical regions, posing a significant threat to global agriculture and fruit production.

Diseases and host plants: This fungus is responsible for several devastating conditions, including stem-end rot, dieback, root rot, and necrotic lesions on fruits. Its host range is remarkably broad, affecting vital crops such as cacao, citrus, mango, banana, rubber, and various woody ornamentals, leading to severe economic losses.

Biology and lifecycle: The pathogen survives as mycelium or pycnidia in diseased plant tissue and crop debris. Under favorable conditions, it releases large amounts of pycnidiospores, which are disseminated by wind-blown rain and insect vectors. Once they reach a host, they germinate and penetrate through wounds, pruning cuts, or natural openings to establish deep infection within the tissues.

Conditions for development and pathogenicity: Botryodiplodia rhodina flourishes in warm temperatures ranging from 25°C to 30°C coupled with high humidity. Its high level of pathogenicity is attributed to the rapid secretion of cellulolytic enzymes that quickly decay plant tissues, causing significant structural failure in stems and total spoilage of fruit, often occurring post-harvest.

Control and management measures: Mitigation strategies focus on sanitation, such as removing and destroying infected branches to eliminate inoculum sources. Post-harvest management includes treating fruits with hot water or fungicide dips and ensuring cool, dry storage conditions. Preventive applications of systemic fungicides in the field, alongside pruning techniques that reduce wounding, are essential for effective management.