Citrus Greening (Huanglongbing)

Symptoms

Citrus Greening (Huanglongbing)

  • Symptoms can be found year round, but are most easily seen from September through March
  • The disease affects all parts of the tree canopy -  leaves, twigs and fruit
  • As the disease progresses, it will cause the whole tree to decline

    Leaf Symptoms

  • Leaf symptoms include blotchy mottle, yellow veins, vein corking or green islands
  • Yellow veins, vein corking or green islands are not diagnostic alone
  • Blotchy mottle is the best diagnostic leaf symptom of greening
  • Blotchy mottle: a random pattern of  yellowing (chlorosis) on leaves that is not the same on the right and left sides of the leaf
  • Yellow veins can be confused with other diseases (e.g. foot rot) or damage (e.g. broken or girdled limb)

    Leaf Symptoms

    Pen Test for Leaves

  • A simple procedure to determine if symptoms are the same on both halves of a leaf
  • Draw two circles on opposite halves of the leaf
  • Is the pattern the same in both circles?
  • Different patterns indicate potential greening if other problems have been ruled out

Nutrient

Nutrient Deficiency

Greening

Greening

 

Fruit Symptoms

  • Fruit external appearance may be lopsided, misshapen or small green fruit
  • The fruit would taste salty and bitter
  • The internal appearance may have aborted seeds, yellow stain beneath the calyx button and/or a curved central core

Greening fruit symptoms

Tree Appearance

  • Yellow shoots
  • Twig dieback
  • Stunting
  • Off-season bloom
  • Overall tree decline

Tree appearance

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