Pink root of onion

Pink root of onion (Phoma terrestris) s a disease of onions that can cause symptoms very similar to nutrient deficiencies or stress associated with extremely dry conditions.

Symptoms
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.

Prevention
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.