SAN DIEGO — A potentially threatening citrus tree disease was detected in Rancho Bernardo this week, said the County of San Diego Communications Office.

The bacterial disease, known as Huanglongbing (HLB), is a threat to San Diego’s annual citrus crop, which the county says is worth around $115 million. The disease is spread by tiny insects that feed on citrus trees.

In response to the disease, which was found in a residential lime tree, the California Department of Food and Agriculture has declared a new citrus quarantine in a 95 square-mile area. This is in addition to a quarantine that was already in place for the City of Oceanside, the county said.

A map showing affected areas can be found here.

The county said the quarantine order is meant to protect the region’s food supply and support the agricultural economy, along environmental sustainability.

“Unfortunately, Huanglongbing is fatal to citrus,” said San Diego Agricultural Commissioner Ha Dang. “Our goal is to prevent this disease from spreading any further. By working together, we can all protect our food supply, local agriculture, and environment from this devastating disease.”

Plant quarantine explained

What exactly is a citrus quarantine? To reduce the spread of HLB, residents and business owners are restricted from moving citrus nursery stock, plant parts and fruit outside the quarantine boundaries or off their properties.

The only exception, according to the county, is for agricultural businesses that must follow specific requirements for treatment, cleaning and packing commercial fruit before moving it.

Residents in the quarantine area are urged to take these steps to reduce the spread of the tree disease.

— Do not move citrus plants, leaves or foliage into or out of the quarantine area.

— Cooperate with agricultural officials who are inspecting trees, taking samples and treating for the pest.

— Consider removing your citrus tree if you no longer need it.

— Buy citrus trees only from reputable local nurseries.

— Report citrus trees that seem to be sick or dying by contacting the San Diego Department of Agriculture, Weights and Measures at 760-752-4700 or their website.

— Residents can also call the Citrus Pest and Disease Prevention Division’s toll free Pest Hotline at 1-800-491-899 or visit their website.

Though HLB could be devastating to region’s citrus industry, county officials say it’s not harmful to people or animals.