Research: Fighting the Asian Citrus Psyllid and Huanglongbing

Save Our Citrus!

An invasive insect called the Asian Citrus Psyllid (ACP) has infested California. The psyllid can transmit a deadly bacteria called Huanglongbing  (HLB). This disease is fatal to citrus trees, and there is NO cure. Diseased trees produce bitter, hard, and lopsided fruit, and eventually die.

 An orange infected by Huanglongbing.Asian Citrus Psyllid specimenActual size of the Asian Citrus Psyllid

How Can You Help?

  1.  Inspect your citrus trees regularly for signs of Asian Citrus Psyllid populations.
  2. Do NOT move citrus or plant material in or out of your county or across state borders.
  3. Cooperate with agriculture crews placing traps, inspecting trees, and treating for psyllids.
  4. Immature ACP do not have wings and will feed on the new flush of the citrus trees. Immature ACP can be identified by their white excrement (see below).
  5. Control ants on your citrus. Ants protect the psyllids and will interfere with beneficial insects. 

If you suspect that your tree has Asian Citrus Psyllid or is infected with HLB, you should act immediately. Call the California Department of Food and Agriculture (CDFA) at 1-800--491-1899 or contact your county agricultural commissioner's office. You also can visit for more information. 

 Citrus infested with Asian Citrus Psyllid.Citrus infested with Asian Citrus Psyllid.

Other Important Facts

The psyllid is invasive and not normally found in our ecosystem. This pest most likely originated from India or Asia.

Since the psyllid was detected in 2005, Florida has lost more than $7 billion in economic activity related to citrus and more than 6,000 jobs. This is almost entirely the result of HLB's spread.

California has a $2 billion citrus industry that needs protection. Citrus is a staple of California's economy, culture, and history.

Tamarixia radiata - a parasitic wasp native to Pakistan.

Our current management attempts include the use of a parasitic wasp called Tamarixia radiata. Tamarixia originate from Pakistan and are natural predators of ACP. With the help of the California Department of Food and Agriculture, more than 22,000 wasps are bred every week on the Cal Poly Pomona campus. These wasps are currently released by the CDFA in residential areas with citrus.

If you have other citrus-related questions, check out the University of California's Integrated Pets Management website:

 Asian Citrus Psyllid research greenhouse at Cal Poly Pomona