🍊 Citrus Greening

Candidatus Liberibacter asiaticus
Blotchy leaves, lopsided fruit, and the hardest sentence in this guide: there is no cure.

Signs and symptoms

Asymmetrical blotchy mottle — yellow patches that do NOT mirror across the leaf vein — plus yellow shoots, small lopsided fruit that stays green at the blossom end, bitter fruit, a thin canopy, twig dieback, and slow decline over years. That asymmetry is the key distinction: nutrient deficiency is typically symmetrical, mirroring across the vein, while greening mottle is blotchy and one-sided. The bacterium is Candidatus Liberibacter asiaticus — “Candidatus” means the name is provisional because the bacterium has not yet been formally cultured and named. It is spread by the Asian citrus psyllid (Diaphorina citri). Do not diagnose by eye alone: report suspect trees to UF/IFAS Extension or FDACS-DPI for confirmation.

Citrus leaves with blotchy mottle from citrus greening
Citrus greening (huanglongbing) blotchy mottle on sweet orange leaves in Texas. Photo: David Bartels, USDA APHIS, Public domain.
Citrus with greening disease symptoms in Florida
Citrus greening symptoms in Florida. Photo: Mmacbeth, CC0.
Misshapen citrus fruit from citrus greening disease
Misshapen citrus fruit caused by citrus greening (huanglongbing). Photo: USDA APHIS, Public domain.

Plants it attacks

All citrus: orange, grapefruit, lemon, lime, mandarin, and the rest.

What to do

  • Accept the hard fact first: there is no cure for an infected tree. Anyone selling you one is selling hope, not help.
  • Manage psyllids to slow spread to healthy trees.
  • Keep trees vigorous with proper water and nutrition.
  • Remove severely declining trees only after confirmation, not on a guess.
  • Report suspect trees to UF/IFAS Extension or FDACS-DPI rather than diagnosing by eye alone.

Prevention

Buy certified healthy trees from registered nurseries, protect young trees with individual protective covers or screens where practical, scout for psyllids, and do not move citrus material from infected areas.

Nerdy fact: Greening bacteria live inside the tree’s phloem — its sugar highway — clogging the very pipes that move food from leaves to fruit. That is why the fruit stays small, green, and bitter: dinner never arrives.

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