Pacific Pests, Pathogens and Weeds - Online edition

Pacific Pests, Pathogens, Weeds & Pesticides

Citrus Huanglongbing (greening) (230)

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  • 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.
Common Name

Citrus greening, citrus huanglongbing (greening) disease.

Scientific Name

Candidatus Liberibacter asiaticus (Asian form), Candidatus Liberibacter africanus (African form), and Candidatus Liberibacter americanus (South American form). The three pathogens can only be distinguished by molecular tests. The abbreviation is HLB. The name 'huanglongbing' means 'yellow shoot disease'.

AUTHOR Grahame Jackson
Information from Briansky RH, et al. (2014) Florida citrus pest management guide: huanglongbing (citrus greening). U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida. (; CABI (2019) Citrus huanglongbing (greening) disease. Crop Protection Compendium. (; and from (including Photos 1&3) Citrus Greening (Huanglongbing) (2019). UF/IFAS Citrus Research and Education Center. (; and information (and Photo 2) Grafton-Cardwell EE, Daugherty MP (2018) Asian Citrus Psyllid and Huanglongbing Disease (2013) University of California Statewide IPM Program. Agriculture and Natural Resources, University of California. ( Photo 4 HD Catling, Photo 5 Jeffrey W Lotz, Florida Department of Agriculture and Consumer Services,

Produced with support from the Australian Centre for International Agricultural Research under project PC/2010/090: Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production, implemented by the University of Queensland and the Secretariat of the Pacific Community.

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