A tiny pest is a deadly threat to SLO County’s citrus industry

April 17, 2014 

An Asian citrus psyllid, an insect about one-eighth of an inch long that spreads a deadly citrus disease, has been found in San Luis Obispo County.


We’re fortunate to have a diversity of agriculture in San Luis Obispo County. More than 100 crops are grown here, including strawberries, wine grapes and citrus fruit. But the recent arrival of an invasive pest could mean citrus is no longer a part of this mix. As a second-generation citrus grower, that’s not a fate I’m willing to accept.

The pest, called the Asian citrus psyllid, was detected in Arroyo Grande earlier this month and could pose a death sentence to all citrus trees in the area, including the $9 million lemon industry and countless citrus trees in residents’ backyards. The Asian citrus psyllid feeds on the leaves and stems of citrus trees and can infect healthy trees with a fatal plant disease called Huanglongbing, also known as HLB or citrus greening disease. There is no cure for HLB, and once a tree is infected, it will die.

If this disease reaches San Luis Obispo County, it would mean the end of locally grown citrus. My livelihood and that of those who work for me would be gravely impacted. I have 170 acres of lemons in Nipomo and 100 acres in Goleta. My family has spent years cultivating these trees and providing fresh, locally grown fruit to the community. Facing the threat of the Asian citrus psyllid and the fatal plant disease it can spread, we need the support of the community to find and treat for this dangerous insect.

The best way to protect our county’s citrus trees from the disease is to find and stop the Asian citrus psyllid — an act that will take a concerted effort on the part of my fellow citrus growers, homeowners and agriculture officials, who are placing traps and monitoring for the insect around the county.

The Asian citrus psyllid can be hard to find, as it is only about 1/8 of an inch long as an adult and just a tiny yellow-orange dot when it’s young. While residents are encouraged to inspect their trees, it’s also important to let the experts access your property to diligently inspect and treat for the pest. Treatments are provided free of charge by the California Department of Food and Agriculture, and involve pesticides applied to the soil and the leaves. All treatments are applied safely, according to label instructions. By following the label, pesticides can be used to help stop the Asian citrus psyllid while maintaining the health of the environment, including other nearby crops and local pollinators, which play an important role in our region’s agriculture, home gardens, orchards and wildlife habitats.

In addition to cooperating with agricultural officials on psyllid identification and treatments efforts, residents can help save county citrus trees from this pest and the deadly disease it can carry by not bringing citrus plants into the county from Southern California or other areas. The psyllid and the disease have been detected in Los Angeles County and in other states and countries, including Florida, Texas and Mexico. Do not bring back citrus fruit or plants from these areas, because you could unknowingly bring the pest and disease along with them. I encourage you to buy your citrus locally from reputable, licensed nurseries or home and garden centers so you know you’re getting a healthy tree and supporting our local economy.

Everyone in San Luis Obispo County plays a role in preserving the agricultural identity of our region and the fresh citrus trees that have become so iconic to our state. Visit to learn more about this threat and see photos that can help you identify the insect. A free hotline has been set up to easily report possible finds — call 800-491-1899. We all must do everything we can to save our citrus.

Mike Cavaletto is a second-generation citrus grower.

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