San Diego Floral Association
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Friend or Foe: Asian Citrus Psyllid
Reprinted from: November/December 2008, Volume 99, Number 6
Citrus lovers beware; there is a new threat to your trees and citrus-related plants
Adult citrus psyllid and nymphs.
Courtesy of UC Statewide IPM Program, Beth Grafton-Cardwell.
A large portion of San Diego County is now under quarantine for citrus due to a new invading pest, the Asian citrus psyllid. This means that if you are growing citrus or citrus related plants, such as curry plant or orange jasmine, do not transport any of your fruit or any part of your plants outside of the quarantine area. Even if you don’t suspect infection in your plant, transporting fruit, cuttings or plants outside of the quarantine zone is now illegal. It can spread what many experts believe is one of the worst recent pest-borne threats to the California citrus industry. Information on the current, and possibly expanding quarantine zone, is available from the San Diego County Agriculture Commission office.
So, why is the Asia citrus psyllid so dangerous? Like the glassy winged sharpshooter, which has devastated our oleanders, the problem is not with the psyllid itself, but with a bacteria that is harbored by the insect. This bacteria causes a disease named Huanglongbing (HLB), which destroys the production, appearance and value of citrus trees. It has caused devastation to the citrus industry in Asia, in addition to other foreign locales, and is currently wrecking havoc in Florida. Infected trees produce bitter, inedible, misshapen fruit and eventually die from the disease. Unfortunately it may take years before the disease is evident, and by then the only option is to destroy the infected plant.
The Asian citrus psyllid was first caught locally in a sticky trap near Sweetwater Reservoir in late August. Over 250 additional psyllids were found nearby through a citrus inspection the following week. The psyllid could become an important pest in our county if the current infestation cannot be eradicated. With our current state budget crisis, it is possible that there will be no posse or funds available to round up these bad guys.
To identify this pest, you’ll need to do a Sherlock Holmes with your magnifying glass to inspect your plants. The Asian citrus psyllid is tiny and primarily inhabits new foliage. Look carefully at the leaves, especially at new foliage to see if they are harboring the tiny one-eighth to one-sixth inch insects. They are mottled brown and shaped like a maple leaf key, oblong and tapering down to a bulge with tiny reddish eyes. The heads are down and the body sticks up at about 45 degrees. More static and probably more evident are the yellow orange almond shaped eggs tucked into the curl of tender new leaves. Check your trees monthly and even weekly during spurts of new leaf growth.
If you find the insect, secure it in a clear container and contact the San Diego County Agriculture Commission. You can take it to the office at 5555 Overland Drive, Building 3, call 858-694-2741 or email email@example.com. Residents of other counties should contact their local agriculture commission using contacts found on a website which has been devoted to identifying this lethal pest: www.californiacitrusthreat.org.
If you are interested in planting a new citrus tree, your choices will be limited to nurseries that have been certified through a rigorous program to assure the trees harbor none of the insects. At this time, Evergreen Nursery citrus trees have been certified. —Lucy Warren
Mission: To promote the knowledge and appreciation of horticulture and floriculture in the San Diego region.