CITRUS TREE ALERT

The California Department of Food and Agriculture (CDFA) has detected the presence of Candidatus Liberibacter asiaticus (CLas), the bacteria causing the citrus disease huanglongbing (HLB), in citrus trees and the Asian citrus psyllid (ACP) in several cities across Orange County. 

HLB is considered one of the most devastating diseases of citrus in the world. 

HLB, spread by ACP, is a severe threat to citrus crops, leading to tree death within 2 to 5 years. If not controlled, it could rapidly spread, severely impacting California’s $3.63 billion citrus industry, resulting in job losses and economic damage. The CDFA’s response includes surveillance and treatment strategies to manage the infestation, based on input from various experts and previous control efforts in other states. Despite efforts, there is no cure for HLB, making it crucial to act quickly. 

What are the Symptoms?

Symptoms of HLB include yellow shoots with mottling and chlorosis of the leaves, misshapen fruit, fruit that does not fully color, and fruit that has a very bitter, rancid taste, which makes it inedible for human consumption. These symptoms often do not appear until a minimum of two years after infection, making this disease particularly difficult to contain and suppress.

How is CDFA responding? 

Infected host plants are destroyed as soon as they are discovered. However, due to the length of time it takes for symptoms to appear on infected plants, which is two to five years, new infestations continue to be discovered. 

If the current infestation is not abated immediately, ACP will likely become established in neighboring counties and could pave the way for a statewide HLB infestation. 

CDFA evaluated possible treatment methods in accordance with integrated pest management (IPM) principles and have determined that it is necessary to address the imminent threat posed by HLB using currently available technology in a manner that is recommended by the HLB Task Force.

What is the Work Plan? 

• Emergency Program Area: Covers a 5-mile radius around HLB detections in Orange County; may be amended if delimitation areas expand.

• Duration: Valid until July 26, 2026, to allow sufficient time for detecting and assessing HLB-infected plants.

• Survey and Testing:

  • Inspect host plants within a 50 to 250-meter radius around HLB and ACP detection sites at least twice a year.

  • Collect ACP and plant tissue samples for testing at USDA-accredited labs.

• Treatment:

  • For ACP:

    • Voluntary treatments within 50 to 250 meters of CLas-positive ACP detection sites unless HLB is detected nearby.

    • Mandatory treatments within 50 to 250 meters of HLB detection sites.

    • Use Tempo® SC Ultra for adult and nymph control; reapply up to three times annually.

    • Use Merit® 2F (soil drench) or CoreTect™ (tablets) for long-term nymph control; reapply once annually.

• Physical Control:

  • Destroy HLB-positive plants using mechanical means to prevent disease spread.

Resident Information 

• Residents of affected properties shall be invited to a public meeting or contacted directly by CDFA staff. Consultation with the California Department of Pesticide Regulation, the Office of Environmental Health Hazard Assessment, and the county agricultural commissioner’s office will be provided at the public meeting or upon request to address residents’ questions and concerns.

• Residents shall be notified in writing at least 48 hours in advance of any treatment in accordance with the Food and Agricultural Code (FAC), sections 5771-5779. Following the treatment, completion notices are left with the residents detailing post-treatment precautions. 

• For any questions related to this program, please contact the CDFA toll-free telephone number at 800-491-1899 for assistance. This telephone number is also listed on all treatment notices. The following treatment information and additional resources are posted on CDFA’s website

Learn more HERE.