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Onion: cultural control of Sour skin disease

Sour skin disease of onion

Causal Agent: Burkholderia cepacia (syn. Pseudomonas cepacia)


  • Field symptoms often appear as one or two leaves that have turned a light brown color.
  • A watery rot develops at the base of the leaves and proceeds into the neck, allowing the leaves to be easily pulled from the bulb.
  • As the disease progresses the outer bulb scales are infected.
  • However, the outer most bulb scales and inner bulb scales may not become infected, which distinguishes sour skin from slippery skin where inner bulb scales are infected first.
  • Infected scales develop a slimy pale yellow to light brown decay and may separate from adjacent scales allowing the firm center scales to slide out when the bulb is squeezed.
  • Infected bulbs often have an acrid, vinegar-like odor due to secondary invaders, especially yeasts, colonizing decaying bulbs.


  • The use of furrow irrigation, instead of overhead and recycled irrigation water, will reduce losses from this disease.
  • Do not damage foliage prior to harvest or bulbs during harvest since B. cepacia enters the plant primarily through wounds.
  • Onion crops should be harvested at maturity and the bulbs dried quickly.
  • Storing onions at cool temperatures 0°C (32°F) with adequate ventilation to prevent condensation on the bulbs.
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Please note that this is the opinion of the author and is Not Certified by ICAR or any of its authorised agents.