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The Disease: Huanglongbing (HLB)

Leaves of a citrus tree with Huanglongbing citrus greening disease

HLB threatens our locally produced citrus and Californians’ ability to grow citrus. The disease:

Destroys production, appearance and value of citrus trees.
Produces bitter, inedible, misshapen fruit.
Is fatal to citrus trees.

What is Huanglongbing?

Huanglongbing (HLB), also known as Citrus Greening Disease, is a bacterial plant disease that – while not harmful to human health – destroys the production, appearance and economic value of citrus trees and the taste of the fruit and juice. It is the most serious citrus plant disease in the world and once a tree is infected, there is no cure. Diseased trees produce bitter, inedible, misshapen fruit and eventually die. HLB has already destroyed citrus fruit production in various parts of the world, including domestically, in Florida, where the industry is now in rapid decline.

Image of fruit and leaves spoiled and mottled by Huanglongbing

HLB produces yellow mottling and shoots, and small, hard fruit with bitter taste.

How will HLB enter California?

HLB will arrive in California in infected citrus trees brought into the state or by the Asian Citrus Psyllid picking it up from an infected plant in a region such as Florida and being transported into California by ship, truck, car or mail.

Van image showing that you should check for citrus psyllids on plants entering
California

Citrus trees shipped into California can unknowingly be transporting the pest or diseased trees.

How is it spread?

HLB can be spread by grafting infected plant tissue onto another plant, but it is more likely to be moved around by infected psyllids. Once the Asian Citrus Psyllid picks up the disease, it carries it for the rest of its life (weeks to months), spreading it from tree to tree as it feeds. HLB can also be spread by plant grafting and movement of infected plant material. Inspection for the Asian Citrus Psyllid is our first line of defense and citrus tree owners should inspect often.

What’s the threat to California?

Image of a Homeowner with Citrus Trees dying from Huanglongbing

A Florida homeowner saw first-hand the effects of HLB, as trees in this backyard became infected and died.

HLB and the Asian Citrus Psyllid, threaten not only local farms and farmers that we count on for our fresh, healthy, locally produced citrus, but also consumers’ ability to buy and grow citrus fruits in their backyards.

What types of trees can be infected with HLB?

Citrus trees - including oranges, lemons, tangerines, limes and grapefruit, kumquats and plants closely related to citrus - can be infected with HLB.