FAQ's

1. What is Citrus Greening?

Huanglongbing (HLB), commonly known as Citrus Greening, is a bacterial disease that impacts all citrus varieties and some plants in the Rutaceae family, including ornamental plants like boxwood and orange jasmine

2. What causes Citrus Greening?

HLB is triggered by the bacterium Candidatus Liberibacter asiaticus, which resides in the tree’s phloem, the vascular system that transports nutrients. Harmless to humans, the bacteria are spread by the Asian citrus psyllid, an insect that acquires and transmits the bacteria from infected trees. The bacterium multiplies in both the plant and the psyllid..

3. Why is greening so bad?

In plants, water flows through the xylem, while sugars and minerals travel via the phloem. The HLB bacterium damages the phloem, disrupting nutrient flow, similar to restricted blood flow in a human’s damaged vascular system. This causes poor tree health. The bacteria also attack the roots, impairing their function even before leaf symptoms appear. As the tree attempts to grow new roots, the damage is already done, leading to a steady decline in health. Over time, infected trees become unproductive, with smaller trees succumbing faster. Declining trees should be removed.

4. How does citrus greening spread?

HLB spreads primarily through the Asian citrus psyllid (ACP), which uses its piercing, sucking mouthparts to transfer the bacteria to and from the tree’s phloem. The second method is grafting, which is illegal for Florida homeowners to prevent accidental disease spread. Only certified nurseries may graft citrus trees using clean, certified stock. The disease does not spread through seeds.

DISEASE IDENTIFICATION

1. How can I diagnose citrus greening?

Symptoms vary between fruit and leaves:Fruit symptoms: Lopsided, misshapen, small, green fruit with color inversion during ripening (color changes from the calyx button downward, unlike healthy fruit, which colors from the blossom end upward).Leaf symptoms: The hallmark is a blotchy mottle pattern, asymmetrical across the leaf’s midvein. Other signs include yellow or corky veins, though these can also result from broken limbs, Phytophthora disease, or Boron deficiency.

Source--University of Florida