Asian Citrus Psyllid is Spreading in California

[From the December 2014 issue of the UC IPM Green Bulletin]

In August 2012, we wrote about the Asian citrus psyllid (ACP) in UC IPM's Green Bulletin newsletter. At that time, ACP was found only in San Diego, Imperial, Riverside, San Bernardino, Los Angeles, and Orange counties. It has since been detected in Ventura, Santa Barbara, San Luis Obispo, Fresno, Kern, and Tulare counties, and in the last three months has been found in San Joaquin and Santa Clara counties (Figure 1).  

Because ACP can transmit the bacterium causing the most devastating disease of citrus in the world, huanglongbing (HLB) or citrus greening, it is imperative that this pest be managed as intensely as possible (Figure 2). To keep the psyllid from spreading further, ACP host plants (citrus and close relatives) in all or part of these counties are under quarantine and cannot be moved out of the quarantine area.

We cannot stress strongly enough that landscape professionals, including residential and maintenance gardeners, can play a major role in minimizing the spread of this pest or HLB. To build upon the information from 2012:

• Always purchase citrus trees from a reputable nursery that sells certified disease-free trees.
• Uncertified trees may provide the insects with a source of disease they can pass on to other trees!
• Be careful not to move any citrus trees out of the quarantine area to uninfested areas. If you purchase a citrus plant from a nursery that is within an ACP quarantine area, it will have a blue or yellow tag on it that requires the plant to stay within the quarantine area. Purchase plants close to where you plan to plant them!
• As you are planting or caring for citrus, carefully check the leaves and stems for psyllids. Visit the CDFA Plant Health and Pest Prevention Services web site for photos of the pest and the Citrus Pest and Disease Prevention Program web site. If you or your customer suspects you have seen the pest or disease, immediately call the CDFA Hotline 1-800-491-1899. When you report the psyllid, CDFA personnel will tell you if they will be treating the reported trees or if you are to manage the ACP population yourself.
• Consult the UC IPM Asian Citrus Psyllid Pest Note for information about how you can help in the effort to control psyllids.
• It is very important to know if you are in an ACP infested area and; if you are, to handle green waste carefully. If you are pruning citrus or other ACP hosts, double bag prunings before transporting them to avoid moving ACP to new areas.
• Landscape professionals should educate clients to dry out their clippings before placing them in green waste bins to avoid spreading ACP.
• If you think you have seen the disease, CDFA personnel will take leaf samples to confirm infection of the tree by a biochemical test; and if the infection is found, regulatory actions such as tree removal will take place.

Be vigilant and help to protect California's citrus trees!

Find out more information and see official quarantine rules at the CDFA web site.