Agricultural officials warned local citrus-tree owners after discovering evidence of a tiny pest known to carry the disease Huanglongbing on several citrus trees in Los Angeles County.
HLB is an insect-borne bacterial disease that commonly attacks citrus trees and can severely impact the county’s lemon-growing industry, which was valued at over $12.7 million in 2010. Officials recently discovered the Asian citrus psyllid — the HLB carrier insect that transmits the disease after feeding on infected plant tissue and moving to healthy plants — on trees in Hacienda Heights, prompting LA officials to quarantine a 93-square mile section of the community.
The ACP is a brown insect the size of an aphid that lays bright yellow-orange almond-shaped eggs clumped together on young leaves. The ACP consumes sap and secretes large amounts of honeydew that can lead to mold growth on the host plants.
A partial quarantine was applied to all of Santa Barbara County after psyllids were discovered in Ventura County in 2010.
According to Santa Barbara County Deputy Agricultural Commissioner Guy Tingos, the insect first appeared in California in 2008. HLB usually surfaces about two years after the carrier insects are discovered.
“We are concerned about the insect because it spreads the disease,” Tingos said. “Where the psyllid moves, the disease typically follows. It was sort of expected that the disease would eventually appear when we first detected the insect. Now, about four years later, it shows up just as we predicted.”
Tingos said Santa Barbara’s quarantine from the San Marcos Pass to Carpinteria prohibits the exportation of citrus trees from the area and requires that the stems and leaves of fruit be removed before transportation.
Steve Lyle, spokesman for the California Department of Food and Agriculture, said local growers should regularly inspect citrus trees for signs of the disease.
“The primary symptom [of HLB] is the yellowing and mottling of leaves,” Lyle said. “We encourage people to be vigilant in looking out for the psyllids or the disease and to keep us informed.”
Joanne McGrath of McGrath Family Farm in Camarillo plants over 50 different types of produce for shipment to restaurants in Ventura, Los Angeles and Santa Barbara County.
McGrath said the disease inevitably branches out due to widespread transportation and distribution.
“There is not a single solution or answer to this,” McGrath said. “It seems that if we have global marketing, diseases like [HLB] are bound to happen. It was not a matter of if, just a matter of when. Farmers could possibly think about being more diversified instead of relying on one thing. It kills that there is no cure.”
According to a CDFA press release, the disease targets the vascular system of plants and can stunt growth. There is no known cure and trees typically die within a few years.
Additionally, Tingos said HLB renders fruit inedible and misshapen with visible dark seeds and bitter juice.
“The fruit cannot be used in any way, not even as juice,” Tingos said. “The fruit industry is so large here in California. If the disease spreads into the main citrus-producing Central Valley areas in California, commercial orchards would face a huge blow and the economic impact would be catastrophic.”
Although commercial growers are informed about the disease, Tingos said officials will continue to take necessary precautions to keep psyllids out of local vegetation.
“For homeowners, there is a little bit more concern there because they could potentially not pay as much attention to their trees and tend to move their fruit around more than commercial orchards do, such as sending fruit to the East or taking it to their friends,” Tingos said. “In general, it is best for people not to move backyard citrus around. It is best if it is consumed on property. If fruit is moved, however, those who wish to do so must also think about the quarantine.”
The Agricultural Commissioner’s Office offers free testing for those who suspect an ACP infestation. Contact the CDFA toll-free pest hotline at 1(800) 491-1899 or visit www.cdfa.ca.gov for more information.