Citrus Greening

Citrus Greening, also known as Huanglongbing (HLB), is considered to be the most destructive disease of citrus. Once a tree is infected, there is no effective control or cure for the disease.  This disease poses no threat to humans or animals, but can destroy all types of citrus trees, including orange, grapefruit, lemon, lime, kumquat, tangerine, and relatives like orange jasmine. This disease is a serious threat to our South Texas citrus industry. Infected trees may produce misshapen, unmarketable, bitter fruit. Citrus greening reduces the quantity and quality of citrus fruits, eventually rendering infected trees useless. An infected tree produces fruit that is unsuitable for sale as fresh fruit or for juice. The Asian citrus psyllid, which spreads citrus greening, is no bigger than the head of a pin. The infected insect spreads the disease as it feeds on the leaves and stems of citrus trees. Once the Asian citrus psyllid picks up the disease, it carries it for the rest of its life. Citrus greening is then spread by moving infected plants and plant materials such as bud wood and even leaves.

Signs and symptoms to look for:

Click images to enlarge.

Visible Asian citrus psyllids (ACP) or waxy psyllid droppings

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Asymmetrical blotchy mottling of leaves (this is the most common symptom seen in Texas)

new greening imageYellowing leaves 4Yellowing leaves 5Mexican Lime - edited with creditPhoto of irregular yellowing that I use to show residents.

Raised, thickened, or corky veins

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Lopsided, bitter, hard fruit with small, dark aborted seeds

Misshapen Grapefruit_Weslaco - edited

Small and off-color fruit

Yellow shoots

Twig dieback

Citrus greening disease was first reported to have occurred in Asia during the late 1800s and the disease has already caused devastation in Asia, Africa, the Arabian Peninsula and Brazil. In addition to Texas, the disease is currently found in California, Florida, Georgia, Louisiana, Puerto Rico, South Carolina and the U.S. Virgin Islands.