An outbreak of the citrus plant disease Huanglongbing (HLB) has been reported in North Long Beach, according to the California Department of Food and Agriculture (CDFA).
HLB is spread by the Asian citrus psyllid, an invasive insect. When the psyllids feed on a plant infected with the bacteria that causes HLB, it then carries the disease to every healthy plant it feeds on afterwards.
HLB eventually kills trees, but trees can be asymptomatic for years. Symptoms can include yellowing leaves, bitter-tasting fruit, and limb and twig dieback (when parts of a plant progressively die, spreading from the outer edges to the inside), according to the University of California Agriculture and Natural Resources.
There is currently no treatment or cure for HLB. The disease can affect all species of citrus trees, such as lemons, oranges, grapefruits, pomelos, calamansi and more.
According to Victoria Hornbaker, director of the CDFA’s Citrus Pest and Disease Prevention Division, the disease was first discovered in North Long Beach in December 2022, and seven infected trees have been found in the area since then.
According to Hornbaker, citrus tree owners should watch for signs of HLB such as: yellow shoots sprouting from the middle of the tree, blotchy yellow leaves, misshapen fruit, fruit that won’t ripen and excessive dropping of fruit.
The CDFA has the authority to test for HLB in areas where an infection has been confirmed, and will go door-to-door looking for citrus trees to test. To test a tree for HLB, CDFA personnel will take around 20 leaves and send them to a laboratory in Sacramento for testing. If a tree is found to be infected with HLB, it will usually be sprayed with pesticide and removed within a week.
Property owners who believe their citrus trees may be infected with HLB are urged to call CDFA’s exotic pest hotline at 1-800-491-1899, so CDFA can take samples and conduct testing to confirm if the tree is infected.
“We don’t advocate for removing healthy trees in the area at all,” Hornbaker said. “What we do want folks to do though, is keep an eye on their tree.”
The California Citrus Growers Association, a cooperative of industrial citrus growers, provides funding for CDFA to remove HLB-infected trees from residential properties, at no cost to property owners.
The citrus industry has a vested interest in preventing the spread of HLB since the disease poses a significant risk to citrus crops.
While HLB hasn’t infected agricultural citrus in California yet, the disease has plagued Florida’s citrus farms, severely impacting crop production.
In 1998, the first Asian citrus psyllids discovered in the U.S. were found in Florida, and in 2005 Florida suffered the first domestic case of HLB. As of 2013, Florida’s citrus industry had lost around 20 million trees, according to the United States Department of Agriculture.
“Florida has been devastated by HLB,” Hornbaker said. “Their production is the lowest it’s ever been […] And what you see with, for instance, Florida juice producers, for the most part it’s really difficult to find Florida-grown citrus fruit juice that isn’t mixed with other things like strawberry or pineapple or other fruits that would kind of mask the off taste of an HLB infected fruit.”
To keep California’s citrus industry from meeting the same fate as Florida’s, Hornbaker said it’s important to immediately address HLB infections in residential areas before it spreads to California’s rural areas.
“The main thing is it could potentially be an industry-ender for us in California,” Hornbaker said. “If it gets a foothold in our commercial groves and moves into other commercial groves, we will really see a decline in our citrus industry.”
While HLB only recently arrived in Long Beach, the disease is already rampant in the cities of Anaheim, Orange, Garden Grove and Santa Ana.
To help curb the population of Asian citrus psyllids, the CDFA has released a species of parasitic wasps, tamarixia radiata, in Long Beach and throughout Southern California. This parasitic species of wasp lays an egg on the Asian citrus psyllids, and when the larvae hatches it devours the host.
Homeowners who want to protect their trees before they get infected with HLB can purchase pesticides or protective mesh nets from home & garden centers and online. While these options provide protection against Asian citrus psyllids, both have drawbacks. Certain pesticides are toxic to bees, and should not be used when a tree’s flowers are in bloom. Mesh nets prevent pests as well as pollinators from accessing the tree, so residents will have to pollinate these trees by hand.
To find out how close residents are to a confirmed outbreak of HLB, they can visit http://geodata.ucanr.edu/hlb_proximity/ to use an online map created by the University of California Agriculture and Natural Resources.
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