Infection dynamics of Fusarium mangiferae, causal agent of mango malformation disease

Area of Science:

• Plant Pathology
• Mycology
• Horticulture

Background:

• Mango malformation disease (MMD) causes significant economic losses in mango production worldwide.
• Fusarium mangiferae is the primary causal agent of MMD, affecting mango trees.
• Understanding the pathogen's life cycle and infection dynamics is crucial for disease management.

Purpose of the Study:

• To investigate the in vitro conditions affecting Fusarium mangiferae germination and growth.
• To determine the infection pathways and colonization patterns of F. mangiferae in mango plants.
• To elucidate the disease cycle of mango malformation disease.

Main Methods:

• In vitro studies on conidial germination and colony growth under varying temperatures and wetness durations.
• Inoculation experiments on mango buds, leaves, and soil to assess colonization.
• Field sampling of leaf disks and branches to monitor pathogen presence and airborne inoculum levels.

Main Results:

• Optimal germination and growth of F. mangiferae occurred at temperatures above 5°C, peaking at 28°C and 25°C, respectively.
• Conidial germination required at least 2 hours of wetness, peaking after 8 hours.
• Inoculum from malformed inflorescence debris significantly increased bud colonization (52% and 20%) compared to controls (0%).
• Pathogen detected in roots 19 weeks post-inoculation, but not in aboveground parts without symptoms.
• Peak F. mangiferae propagule incidence on leaves in June-July; airborne infections highest in May-June.
• Colonization was significantly higher in node sections than internodes of infected branches.

Conclusions:

• Environmental factors like temperature and wetness are critical for F. mangiferae development.
• Malformed inflorescence debris is a significant source of inoculum for bud infection.
• F. mangiferae exhibits distinct infection dynamics and colonization patterns in mango, with nodes being preferential sites.