The Agricultural Commissioner’s Office announced last Monday that Santa Barbara County citrus plants have been placed under quarantine following the discovery of six Asian citrus psyllids (ACP) within county lines.
Non-lethal on their own, ACP prove fatal to citrus when infected with the plant disease Huanglongbing (HLB), for which there is no cure. Santa Barbara is the latest addition to a slowly expanding HLB quarantine zone in California, which prevents commercial citrus plants from moving outside of the designated quarantine areas and now includes every county between Santa Barbara and San Diego.
According to Santa Barbara Agricultural Commissioner Guy Tingos, although there is no health risk to humans, the potential spread of the disease poses a significant risk to local agriculture.
“It’s a fatal disease,” Tingos said. “It starts by showing symptoms of misshapen leaves and mottled coloring in the leaves. Eventually it gets to the fruit and you start seeing misshapen fruit. The fruit itself turns very bitter, and it’s inedible. And depending on the heath of the tree, anywhere between three to five years, the tree dies.”
Steve Lyle, a spokesperson for the California Department of Food and Agriculture, said California has learned from the citrus industry in Florida, which has struggled periodically with HLB since 2005. Rather than focus on the disease itself, which has not yet been detected in Santa Barbara, Lyle said the county’s main objective now is to preemptively suppress the ACP population.
“We know [from] the history of this pest as it has spread around the world that the disease does catch up with the pest,” Lyle said. “So we believe that it is a matter of time, and so we are interested in doing what we can to control the spread of the pest, and in some cases perhaps eradicate it to help manage the risk of disease spread when the disease in fact arrives.”
However, Tingos also said the likelihood of eradicating ACP is low, given the success of the bug in similar areas abroad.
“The insect and the disease are very closely tied with citrus, so you find the disease and the insect in all the citrus producing areas of the world. It’s in the Middle East, it’s in Asia, it’s in Florida, [and] it’s in Mexico now,” Tingos said. “So anywhere where citrus is produced, the insect and the disease are going to do quite well.”
According to Dr. Carolyn Slupsky, an associate professor at UC Davis’ Food Science and Technology Department who has experience studying HLB, the general public needs to understand the risk of ACP and HLB in order to minimize the risk of a spread through backyard citrus.
“The plant can be infected for many years, it can last for 10 years and I think even longer than that,” Slupsky said. “It doesn’t take long for insects to sort of bite through one tree and then bite through another tree, and by the time you can actually detect that you have an infection, it may very well have infected an entire area.”
In the case of an outbreak of HLB in California, Tingos said the disease could have considerable economic implications.
“We got about 14 hundred acres of lemon production in Santa Barbara County and their annual production is about 12 million dollars,” Tingos said. “So it’s a significant industry here.”
In addition to the economic fallout, an HLB outbreak could have a negative impact on a longstanding Californian tradition, according to Lyle.
“We believe we have a significant amount of residential citrus around California, it is part of the heritage of the state,” Lyle said. “When you look at the names of cities and counties and streets, and the citrus theme that runs throughout … citrus is a big piece of California’s identity, both at people’s homes and commercially, and we want to try to protect both sectors equally if we can.”
The Santa Barbara Agricultural Commissioner’s Office urges anyone who has spotted signs of the disease or pest to call their pest hotline at (800) 491-1899 or to visit http://www.cdfa.ca.gov/phpps/acp/ for more information.
A version of this article appeared on page 4 of April 16th, 2013’s print edition of the Daily Nexus.