UCCE Master Gardeners of Orange County
University of California
UCCE Master Gardeners of Orange County

Asian Citrus Psyllid

Asian Citrus Psyllid (ACP)

ACP adults and nymphs
The Asian Citrus Psyllid (ACP) has been in Orange County since 2008, but did not become a serious threat to citrus trees until a disease, Huanglongbing (HLB) arrived in the Los Angeles area in 2012.

Asian Citrus Psyllids are sucking insects.  When they feed on a diseased tree, they spread the disease to other trees it feeds on, much like mosquitoes and fleas spread disease to people and animals.

There is currently no cure for HLB, and it is fatal to citrus trees.  The best way to protect your trees  is to use a soil drench of Bayer Advanced Fruit, Citrus and Vegetable when you see the psyllids in the fall or spring.  Follow directions on the package.  More is not better!

If you think your tree has HLB disease, call 1-800-491-1899 to make a report.  

You can see a map of where the disease has spread here: Zoomable map of ACP/HLB

HLB leaves
Signs of the disease include misshapen fruit and mottling of the leaves.  Nutritional deficiencies can cause yellowing of citrus leaves, but the yellowing is usually symmetrical on the leaves.  Yellowing from HLB is more blotchy and not uniform.  It may occur on one side of the midvein, but not on the other side of the leaf.

To prevent the spread of the disease, no citrus trees, plant materials, or fruit with leaves should be moved around the county.  If you want to share your fruit, be sure all leaves are removed and wash it.

More resources, including a video, are available here: Resources for Homeowners

If you can’t find the answer on the site, don’t despair! We also have the capacity to personally assist you through our hotline.  Just contact us by email or by phone (voicemail) at 949 809-9760 and we will respond to your inquiry.
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