Insect That Carries Disease Deadly to Citrus Trees Found in Placer County

Auburn, CA (MPG)  |  Source: Robert Miller, County of Placer
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Asian citrus psyllid, a small insect that can carry a devastating citrus tree disease, has been detected in Placer County. The disease, called Huanglongbing, and is also known as HLB or citrus greening disease, will kill any tree it infects and there is no known cure, other than prevention.

A call to the California Department of Food and Agriculture’s tip line on Sept. 8 brought state inspectors to a property in western Lincoln where specimens were collected from four trees that day. The specimens were positively identified the following day and the trees were destroyed.

Agricultural inspectors from the Placer County Agricultural Commissioner’s office and the state immediately began an inspection of citrus trees in the area and the Asian citrus psyllid was discovered on another tree on an adjacent property. That tree was destroyed, as well.

A public meeting on the discovery, treatment and monitoring plans will be held Thursday, Sept. 22, at Lincoln High School in the multi-purpose room from 5:30 p.m. to 7:30 p.m. The high school is at 790 J Street, Lincoln.

“While the find is of grave concern, it has not affected Placer County’s robust citrus industry. We’re eagerly awaiting the start of our Mandarin season here in a few weeks,” said Josh Huntsinger, Placer County Agricultural Commissioner. “We don’t believe there will be any immediate effect on our citrus trees and we’re open for business as usual. At this point, the pest has only been found on four backyard trees in a small area of western Lincoln and we’ve hopefully stopped its spread.”

Inspectors have placed traps in trees in a 1.5-mile radius of the infected trees. The state, at the request of Placer County, is expected to approve emergency regulations establishing a 5-mile quarantine radius from the discovery site. The quarantine will encompass most of Lincoln, a portion of Rocklin and a large swath of unincorporated Placer County. This action will prohibit the transportation of any backyard citrus fruit, trees, tree cuttings or root stock to anywhere else, inside or outside of the quarantine boundaries.

The county will continue to conduct additional monitoring. That will include visual surveys of neighborhoods, insecticide treatment of citrus trees and intensive detection trapping. Additional information on these activities will be presented at the public meeting.

HLB is not harmful to humans or animals, but it is always fatal for citrus trees. The insects infest the citrus trees by laying eggs into new growth. If the psyllid carries HLB and transmits it to the tree, it will slowly die, though sometimes symptoms will not show up for several years.

Placer County wants to increase the public’s awareness of not only what the disease can do, but how to avoid bringing it to the foothills. Transporting citrus trees, rootstock or fruit with attached leaves from quarantined areas, in addition to being illegal, can subject you to hefty fines and give the psyllid the avenue to bring disease to our citrus trees.

The discovery in Placer County marks the farthest north the insect has been found since it was first detected in Southern California in 2008. The last discovery was in San Joaquin County in July.

For additional information: Asian citrus psyllid