For the first time, a citrus tree in Southern California was found to be infected with a disease that could wipe out citrus plants across the state.
The infected lemon tree was found a few weeks ago in Los Angeles County. California's nearly $2 billion citrus industry is now in jeopardy.
The disease can affect all citrus plants, which is why officials say they need local homeowners to be the first line of defense.
Ted Batkin, the president of the California Citrus Research Board, said citrus tree owners should be on high alert.
"There's no known cure for the disease in the tree," he said. "Once the tree's infected, it's toast."
The disease causes leaves to look unusually yellow and is called huanglongbing or HLB. It is a bacteria transmitted by the tiny insect known as the Asian citrus psyllid.
Transmission starts when a psyllid feeds on an infected tree and then spreads the infection to a healthy tree.
The bacteria starve the tree by blocking nutrients. Eventually the fruit stops maturing and stays bitter, inedible and often becomes misshapen.
California's citrus industry ranks number one in the nation in terms of value, number two in terms of production. Eighty percent of fresh market oranges come from California, making it the country's main source.
"Our strategy is to test as many of the psyllids as we can capture," said Batkin.
So far, no infected psyllids have been detected in San Diego County, even though the state's first insects were discovered in the county in 2008.
Batkin said that the psyllid lays its eggs on the tips of areas where new leaves are sprouting.
"That doesn't mean that they're infected, but if you have the psyllid, then it's possible," he said."
Experts ask that citrus tree owners check the trees regularly for psyllids and their eggs. They are also asked to look for abnormally yellow leaves in clumps.
"We don't want homeowners to lose their trees," said Batkin. "It's part of California. It's part of who we are here."
Local citrus tree owner Kris De Klerk could not agree more.
"I love being able to tell my family back in the Midwest I have citrus trees in the backyard," he said. "I think I'm going to start checking it more often."
Florida's citrus industry has been devastated by HLB, losing more than 150,000 acres in four years, according to Batkin. That's about 10 to 15 percent of its trees every year.
To report a citrus tree that may be infected or an insect sighting, CaliforniaCitrusThreat.org. You can also call the California Department of Food and Agriculture's hotline: 1-800-491-1899.
