ASIAN CITRUS PSYLLID
By Leonard Cicerello UCCE Master Gardener
Why do I have a yellow sticky card on my lemon tree? Jack, Los Osos
Periodically, insects from other countries end up in California and can create serious problems for farmers and homeowners. Since these insects are new to the area, they have no natural predators here. Therefore, it takes a lot of time and money to figure out how to control them or eradicate them, if necessary. New insects find their way to California more often that we might realize. The Center for Invasive Species at UC Riverside reports that an average of 6 new species becomes established in California every year resulting in an estimated $3 billion in economic losses.
The Asian citrus psyllid (ACP) was found in Southern California in 2008 and has since made its way up the coast and to the San Joaquin Valley. ACP is mottled brown in color and about the size of an aphid, approximately an eighth of an inch long. They feed on all varieties of citrus including some closely related ornamentals like mock orange and orange jasmine. It prefers new tender growth and injects a salivary toxin while feeding that causes the new leaf tips to twist or burn back. The bacterium that it injects causes the disease Huanglongbing (HLB). HLB causes shoots to yellow and results in asymmetrically shaped fruit. The disease can kill a tree within 5 to 8 years and there is no known cure for the disease.
A biological control program began in 2012 with the release of a tiny wasp, Tamarixia radiata. This wasp parsitizes ACP and is completely harmless to pets and humans. Researchers continue to monitor and evaluate Tamarixia and its ability to manage ACP.
County agriculture officials are working closely with the California Department of Agriculture (CDFA) to monitor for ACP by placing yellow sticky cards in commercial orchards and residential trees. The public can help stop the spread of ACP by not moving citrus plants between counties. If you have citrus in your yard, examine the new tender growth for any signs of the pest. If you suspect ACP, contact the CDFA Exotic Pest Hotline at 1-800-491-1899.
For more information, download the free UC ANR publications on ACP and HLB.
http://anrcatalog.ucdavis.edu/pdf/8205.pdf
http://anrcatalog.ucdavis.edu/pdf/8218.pdf