San Diego County’s nearly $115 million citrus industry got a scare this week when officials discovered a tree infected with a citrus greening disease.
San Diego and California officials have set up a 95 square mile quarantine zone centered on Rancho Bernardo in an effort to see how widespread the local Huanglongbing (HLB) infection is.
The infected tree was a lime tree located in a residential yard and it has since been removed.
“There is no cure. It must be treated and removed,” said Alex Muniz, a Senior Environmental Scientist with the California Department of Food and Agriculture. “And that’s really the only way to eradicate the disease from the tree.”
When the disease strikes a plant, leaves and shoots will turn yellow. The tree will also have misshapen and bitter fruit. The disease eventually kills the infected host, but the illness can be spread while the plant is sick.
County officials are notifying local citrus growers, plant nurseries and other businesses.
The illness is spread by a small bug known as the Asian citrus psyllid.
The insect feeds on citrus trees and can ingest the illness, passing it on to an uninfected tree when it moves to feed.
Officials hope the quarantine zone gives them time to isolate the infection and control the spread. Crews are currently surveying the Rancho Bernardo area.
“We’re specifically looking only for citrus,” Muniz said. “If we see citrus and it looks symptomatic we’ll take samples.”
If the samples are positive, crews will return to remove the plant.
The insect that carries the illness has been in San Diego County for more than a decade and the disease was first discovered in Oceanside about two years ago.
Residents are asked not to move citrus plants or leaves out of the quarantine area and consider removing citrus trees they no longer need. They are urged to contact the county if the citrus trees look sick.
Farmers have been on alert for more than a decade when the illness was first discovered in the Los Angeles area.
Most of the Los Angeles basin is under quarantine for HLB because the proliferation of citrus trees in the area makes it easy for the disease to spread.
The disease has already decimated Florida’s citrus groves, crippling a multi-billion dollar industry. The state lost more than 80% of its citrus groves.
San Diego farmers do not want to see that happen here, so the community is working together.
“If the Asian citrus psyllids are present,” said Eric Middleton of the University of California Cooperative Extension office. “When the insect numbers are high, they’re doing area wide sprays. They’re coordinating so that everyone is applying insecticides at the same time.”
Agricultural officials have not had much success containing HLB and they concede that quarantine zones have not contained the disease.
There is hope that the zones slow the spread enough to give scientists a chance to discover a treatment, cure, or way to give trees a resistance to the illness.
