Basic Information

Disease-Carrying Asian Citrus Psyllid
A Death Sentence for California Citrus

What is the Asian citrus psyllid? The psyllid is a tiny, aphid-sized insect that arrived in Florida in 1998 and worked its way to California in 2008.  By itself, it is an irritating pest, damaging the new leaves of citrus trees, but what is more important is that it can carry the bacterium that causes huanglongbing (HLB) disease, also known as citrus greening.

Why is HLB so serious? The bacteria block the nutrient conducting pathways of citrus trees, causing leaves to yellow, fruit to become small, greenish and odd shaped and the juice to turn bitter.  In as little as 5 years, the disease can kill the tree.  There is no currently no cure and so HLB is one of the worst imaginable diseases for citrus.  While HLB doesn’t adversely affect human health, the disease has seriously impacted citrus production in Brazil, India, Asia, the Arabian Peninsula, Africa and now Florida.

How important is it to protect citrus trees? The major citrus producing states in the U.S. are Florida, California, Arizona and Texas. California is the number-one economic citrus state in the nation, ranking first in the U.S. in terms of economic value and second (after Florida) in terms of production.  California produces approximately 80 percent of the nation’s fresh fruit citrus and is the country’s main source (80 percent) of fresh-market oranges (Florida grows oranges mainly for juice).  California also supplies 87 percent of the nation’s lemons.

Where are the psyllid and the disease currently found in North America? Where are the psyllid and the disease currently found in North America? HLB was discovered in a backyard citrus tree in a Los Angeles home in March 2012. The Asian citrus psyllid is found in Florida, Lousiana, Georgia, South Carolina, Texas, Arizona, California, Hawaii and Mexico.  In California, the psyllid has been found on backyard citrus trees in San Diego, Imperial, Orange, Los Angeles, San Bernadino and Ventura Counties.  The disease is found in Florida, Louisiana, Georgia, South Carolina, Belize, Mexico, and in March of 2012 it was found in a single psyllid and a citrus tree in Southern California.  The proximity of Mexico to California and the rapid rise in globalization of trade, travel and immigration make the threat of the disease entering California through infected plants or insects a serious one.  Due to the combination of HLB and citrus canker, it is estimated that the Florida citrus industry has lost nearly 50% of its citrus production in the past 10 years.

How is the disease likely to get to California? How is the disease likely to get to California?  HLB can be spread by grafting infected plant tissue onto another plant, but it is more likely to be moved around by infected psyllids. Once the Asian citrus psyllid picks up the disease, it carries it for the rest of its life (weeks to months), spreading it from tree to tree as it feeds. Inspection for the Asian citrus psyllid is our first line of defense and citrus tree owners should inspect often <>. It is also critical not to transport citrus plants outside of quarantined areas and to not bring citrus plants into California from other states or countries.

For more information on the psyllid click here.