Pink root of onion
|Pink root of onion|
|An onion bulb showing typical symptoms of P. terrestris|
|Phoma terrestris H.N. Hansen, (1929)|
Severely infected plants appear to have a nutrient deficiency or water stress. Roots will range in color from light to deep pink. Can cause roots to become desiccated and shrivel up. Bulbs will be stunted.
Good management practices that reduce plant stress will also reduce the impact of pink rot on yields. Growers should consider an integrated approach for managing this disease in future onion crops and infested fields. Studies have shown that a three to five year crop rotation with a non-host crop can significantly reduce the soil borne pathogen population levels of P. terrestris but will not eliminate it from soil. Resistant cultivars have been developed and should be planted in fields that have high soil population levels of the pathogen. Many of the early Japanese varieties appear to be very susceptible to this disease and should be avoided in heavily infested fields. Soil fumigation can also be used to reduce soil population levels.