Asian citrus psyllid, has not recently received much attention in the news media. However the pest, and the deadly bacterial disease it can carry, are still of great concern.

Kumquats are hosts of ACP and HLB. Photo from UCR Citrus Variety Collection.

The Asian citrus psyllid (ACP) has now been found in eight California counties. Quarantines are in place. The psyllid by itself is not much of a problem; it is its ability to spread the fatal disease that has the potential to devastate both the California citrus industry and backyard citrus throughout the state.

Huanglongbing (HLB) is the name of the disease ACP can carry. Citrus and closely related plants are at risk. The disease is transmitted between plants by the psyllid. The psyllids transmit the disease to healthy plants and trees. After feeding on an infected plant, the ACP will transmit HLB to every other plant it feeds on.

While much outreach has focused on citrus trees, it is important to remember there are other plants that can host both ACP and HLB. This list from the University of Florida provides both the common and Latin plant name for many known hosts. Hosts include: curry leaf, ornamental orange-jasmine, and all the varieties of citrus, including kumquat, mandarin, grapefruit, orange and all of their hybrids.

Please remember to check your citrus and closely related plants regularly for signs of ACP or HLB. General information about this pest disease complex can be found on this section of the CDFA website. For local updates, the Ventura County ACP Task Force is a great source of information.

Orange jasmine (Murraya paniculata) is a close relative of citrus, and a host for ACP. Photo by E.E. Grafton-Cardwell.

The Asian citrus psyllid (ACP) continues to be found in several California counties.  New finds are being made on a weekly basis.  Ventura County and others with this pest remain in quarantine, which means fruit and plant material movement is restricted in these counties.

UC’s Elizabeth Grafton-Cardwell has recently provided an update on LA’s urban infestation. The update can be found on UC ANR’s Citrus Bugs Blog.

UC researchers have begun releasing Tamarixia radiate in Riverside County and soon into Los Angeles county. Tamarixia radiate is a tiny wasp and a natural enemy of ACP. Details of the release and the program can be found on the ANR News Blog.

Invasive species cause billions of dollars’ worth of damage annually. As with all invasive species, it is primarily people who are responsible for ACP’s movement. Please do what you can to avoid moving these pests.

In addition to citrus trees related plants such as this orange jasmine, Murraya paniculata, are hosts to ACP. Photo by E. Grafton-Cardwell.

On March 21, 2011 the Ventura County ACP-HLB Task Force sponsored a workshop for citrus growers, nursery operators and pest control advisors.

The presentations from the workshop have been archived on our website with sound. Titles and presenters are as follows:

• ACP update and overview of treatment protocol for commercial orchards: Beth Grafton-Cardwell, IPM Specialist and Research Entomologist, University of California’s Kearney Agricultural Center, and Director of Lindcove Research and Extension Center.
• Research update regarding biocontrol of psyllids: Raju Pandey, UC Riverside Department of Entomology.
• Research update regarding chemical control of psyllids: Joseph Morse, UC Riverside Department of Entomology.

Please click here to access the workshop recordings.

Asian citrus psyllid infestation. Photo by M.E. Rodgers.

The Asian Citrus Psyllid (ACP) has recently received a lot of media coverage and for good reason.  ACP carries the deadly Huanglongbing (HLB) bacteria, the most serious citrus plant disease in the world.  The disease kills all varieties of citrus trees and related plants such as orange jasmine and Indian curry leaves. The psyllid, about the size of an aphid, does not always carry HLB, but once an ACP feeds on an infected plant the psyllid will carry the disease for life to each plant on which it feeds.

What is particularly troubling about this pest-disease complex is that it can take years for the infected citrus trees to die; therefore, owners of the infected trees may not be aware they have the disease.  While fruit from infected trees can be bitter, misshapen, and inedible, the tree stays up and can continue to be fed upon by psyllids, causing HLB to spread further.

People and our global economy are moving this insect. ACP has spread through Asia, parts of the Middle East, South and Central America.  It has been found in Mexico, Hawaii, Texas, Louisiana, Georgia, Alabama, South Carolina, Florida and arrived in southern California in 2008.  None of the ACP’s found in California have tested positive for HLB.  However, it is highly likely that HLB-infected plants, brought from infected areas, are already here.

What can you do?  Do not bring in plant materials from areas known to be infected with ACP.  If our area becomes infected, do not move any plant materials out of our area. Purchase only certified pest- and disease-free trees from a reputable nursery.  Stay informed. Check your trees regularly for signs of ACP. Report suspected ACP and/or HLB to the County Agricultural Commissioner or the California Department of Food and Agriculture (CDFA).