Bondi Junction NSW, Australia
Fact Sheets
Citrus Huanglongbing (greening) (230)
Pacific Pests, Pathogens and Weeds
Pacific Pests, Pathogens and Weeds


  • Worldwide distribution. In tropics and sub-tropics. On all species and varieties of citrus, and ornamentals, e.g., mock orange or orange jasmine and the curry tree. An important bacterial disease.
  • Patches of yellow on leaves: (i) across veins, (ii) often on one side, (iii) on one shoot or one branch, (iii) seen mostly on newly hardened leaves, before fading.
  • Spread by sap-sucking psyllids, and citrus plant trade.
  • Within a year of infection, leaves fall, fruits are misshapen with uneven colour (bottom stays green), and trees dieback.
  • Biosecurity: many countries are still vulnerable to the disease.
  • Natural enemies: parasitoid wasp are known.
  • Cultural control: nursery plant certification; monthly monitoring; removal of infected trees.
  • Chemical control: use soap, white or horticultural oil sprays, or neem; use synthetic pyrethroids or imidacloprid. These treatments are to psyllid.

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