Iris yellow spot virus

Iris yellow spot virus on onion leaf. Image: Ronald D. Gitaitis, University of Georgia,

  • Iris yellow spot virus affects onion, shallot, leek, garlic, roses, and Rubus species.
  • Damages leaves, roots, whole plant, bulbs.
  • Symptoms of iris yellow spot virus (IYSV) consist of eyespot to diamond-shaped, yellow, light-green or straw-coloured wound(sometimes dead-looking) on the leaves, scape and bulb leaves of onion and other Allium host species. In the early stages of infection, lesions appear as oval, concentric rings. Some green islands can be observed within the necrotic lesions. They usually originate around a thrips feeding point. Infected leaves eventually fall over at the point of infection during the latter part of the growing season. Severely infected fields will age prematurely, and entire areas will turn brown before they collapse.
  • Symptom severity is dependent on host cultivar, timing of infection, overall health of the host at the time of infection, and environmental conditions
  • IYSV does not always kill its host, however, the virus reduces plant vigour, disturbs photosynthesis and reduces bulb size. IYSV infection weakens the plants making them more susceptible to other diseases and pests. IYSV-infected onions grown for seed have reduced seed yield and quality.
  • Found in New South Wales, Victoria, Western Australia and South Australia.
  • There are restrictions for produce entering Tasmania.
  • Carried by Thrips tabaci.


Scientific name: Iris yellow spot virus
EPPRD Category:
Life Form: Virus

Pest Documents

FS: fact sheet

CP: contingency plan

DP: diagnostic protocol