Causal Agent: 

Fungus (Phoma terristris)

Characteristic Symptoms:
Roots of affected plants become pink and brittle and eventually rot.
Necks of infected plants are soft and empty.
Severe infections result to reduced  bulb size.
Conditions for Disease Development:
Once a field becomes infested, the fungus remains in the soil ( as deep as 45cm ) for many years as chlamydospores, pycnidia or pycnidiospores or in plant debris.
Optimum soil temperature for disease development is 24-28º C.
Management and Control:
Use pathogen-free seeds.
Soil fumigation/steaming/solarization and long crop rotation have been shown effective in reducing pink root.
Proper fertilization and irrigation can help prevent the spread of the disease.

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