Huanglongbing

Huanglongbing is a vascular disease of citrus trees that is caused by the Asian citrus psyllid, an insect the size of an aphid. 

Carried from Asia or India, the Asian citrus psyllid was first seen in Florida in 1998. The HLB disease was not identified until 2005. By 2014, huanglongbing (HLB) had caused $4.6 billion in damage to Florida's citrus crops. HLB is now found in California and Texas, as well as Florida.

​HLB can kill a tree within 5 years of infection and there is no known cure at this time. Because of the threat to an entire food industry, infected trees must be destroyed.

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Brownish adult, yellow nymphs, and white wax of Asian citrus psyllids (Michael E. Rogers, UF)

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Preventing the spread of HLB is critical to protecting citrus trees worldwide. In this effort, quarantines are in place that prohibit moving citrus fruit trees, leaves, and stems out of the quarantine area. Contact your county officials to see if you are in a quarantine zone. Looking at the maps below, you can see how a quarantine zone can change in just one year. Since the information to create these maps takes time to put together, you should assume that, if you live near any type of quarantine zone, you should act as though you are in it.

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2015 ACP quarantine map (SCC CA)

2016 ACP quarantine map (SCC CA)

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​Signs of infestation and infection include:

• tiny yellow eggs tucked into new leaf growth
• deformed or blotchy new leaves
• new shoots look burned
• thin, white waxy tubes on new leaf growth
• actually seeing the insect
• leaf mottling
• yellow shoots
• misshapen internal structure
• corky veins
• twig dieback
• small, hard fruit, with a bitter taste

Like other psyllids, the Asian citrus psyllid produces honeydew, which attracts ants and provides a growth medium for sooty mold. Ant traffic can be blocked with the use of sticky barriers.


Other ways you can prevent the spread of this disease:

• do not accept tree cuttings from uncertified sources
• if asked, allow the State Dept. of Food & Agriculture to hang a trap on your property
• do not transport leaves or stems out of the quarantine area
• wash fruit thoroughly before removing it from a quarantine area

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If you suspect or see signs of the Asian citrus psyllid or Huanglongbing disease, immediately contact CALIFORNIA DEPARTMENT OF FOOD AND AGRICULTURE HOTLINE: 1‐800‐491‐1899.

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UPDATE: 3/5/2016
​​Bloomberg reports that Florida citrus growers are now using dogs trained to sniff out the disease to help with early detection and to reduce the spread of this disease.

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UPDATE: 4/1/2018
According to Farm Week Now, half of all Florida citrus growers have gone out of business because of this threat. Also, it is predicted that the 2018 Florida citrus crop will be only one-fourth of what it was 10 years ago. This threat is not to be taken lightly.