FOR THE CITIES OF ANAHEIM, FULLERTON, GARDEN GROVE, HUNTINGTON BEACH, LA HABRA, NORTH TUSTIN, ORANGE, SANTA ANA, TUSTIN, WESTMINSTER, AND YORBA LINDA OF ORANGE COUNTY
Between June 14, 2017 and July 19, 2019, the California Department of Food and Agriculture (CDFA) confirmed the presence of the causative bacterial agent of the citrus disease huanglongbing (HLB) in citrus tree tissue collected from the cities of Anaheim, Fullerton, Garden Grove, Huntington Beach, La Habra, North Tustin, Orange, Santa Ana, Tustin, Westminster, and Yorba Linda, in Orange County.
HLB is a devastating disease of citrus and is spread through feeding action by populations of the Asian citrus psyllid (ACP), Diaphorina citri Kuwayama. In order to determine the extent of the infestation, and to define an appropriate response area, additional surveys took place for several days over a one quarter-square mile area, centered on the detection sites. Based on the results of the surveys, implementation of the CDFA’s ACP and HLB emergency response strategies are necessary for eradication and control. Notice of Treatment is valid until July 19, 2020, which is the amount of time necessary to determine that the treatment was successful.
HLB is considered the most devastating disease of citrus in the world. In the United States, HLB’s unchecked spread in Florida starting in 2006 resulted in devastating impacts on the environment and economy. 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 taste, which makes it unfit for human consumption. These symptoms often do not appear until two years after infection, making this particular disease difficult to contain and suppress. The bacterium that causes the disease, namely Candidatus Liberibacter asiaticus, blocks the flow of nutrients within the tree, causing the tree to starve to death. There is no cure, and trees infected with the disease will die two to five years after infection. The undesirable symptoms of HLB-infected trees result in the trees’ loss of commercial and aesthetic value while they remain hosts for spreading HLB to ACP and other plants. These effects would be catastrophic to California’s natural environment, agriculture, and economy. For example, the effect of HLB’s establishment in Florida resulted in a citrus industry loss of $7 billion. Similar consequences could be expected in California, where the citrus industry is valued at $7.1 billion.
ACP feeds on members of the plant family Rutaceae, primarily on Citrus and Murraya species, but is also known to attack several other genera, including over forty species of plant that act as hosts and possible carriers. The most serious damage to the environment and property caused by ACP—the death and loss in value of host plants--is due to its vectoring the phloem-inhabiting bacteria in the genus Candidatus Liberibacter. However, the psyllids also cause injury to their host plants via the withdrawal of large amounts of sap as they feed, and via the production of large amounts of honeydew, which coats the leaves of the tree and encourages the growth of sooty mold. Sooty mold blocks sunlight from reaching the leaves.
On November 22, 2017, the University of California and the United States Department of Agriculture (USDA) released a briefing paper that indicates, beginning in June 2017, a sharp increase in HLB and HLB-positive ACP detections, cities containing HLB, and ACP nymphs. Prior to the release of the November 22, 2017 briefing paper, the level of HLB risk in California was thought to be relatively stable. Following the release of the November 22, 2017 briefing paper, the Department has become aware of the exponential intensification of the HLB epidemic, as demonstrated by the indicators contained in the paper.
Considering the exponential intensification of the HLB epidemic, emergency action is needed to protect California from the negative environmental and economic impact HLB will cause should it be allowed to remain in this area. The emergency program is based on recommendations developed in consultation with the California HLB Task Force, USDA experts on HLB and ACP, the Primary State Entomologist, the Primary State Plant Pathologist, and the affected counties agricultural commissioners’ representatives who are knowledgeable on HLB and ACP Incorporating these experts’ recommendations and findings, the program requires removal of all HLB-infected trees.
In determining how to respond to this emergency, the CDFA employs integrated pest management (IPM) principles. IPM includes cultural, biological, physical, and chemical control methods. The CDFA considered all relevant factors, data and science and determined that cultural, biological, and chemical control methods would not abate the imminent threat posed by HLB-positive trees or meet its statutory obligations. Therefore, a physical method was selected, which includes removal of any infected host plant. This option was selected based upon minimal impacts to the environment, biological effectiveness, minimal public intrusiveness, and cost.
The November 22, 2017 briefing paper revealed the exponential intensification of the HLB epidemic, which necessitates immediate action to address the epidemic’s imminent threat to California’s natural environment, agriculture and economy. More specifically, in addition to citrus, the HLB/ACP complex threatens loss and damage to native wildlife, private and public property, and food supplies.
In addition, the Secretary is mandated to: thoroughly investigate the existence of the disease; determine the probability that the disease will spread; adopt regulations as are reasonably necessary to carry out the provisions of this code (title 3, California Code of Regulations, section 3591.21); abate the disease from the established treatment area; and prevent further economic damage. See FAC sections 401, 403, 408, 5401-5405 and 5761-5763.
A Program Environmental Impact Report (PEIR) has been prepared which analyzes the ACP and HLB treatment program in accordance with Public Resources Code (PRC), Sections 21000 et seq. The PEIR was certified in December 2014, and is available at http://www.cdfa.ca.gov/plant/peir/.
The treatment plan for the HLB infestation shall be implemented as follows:
1. Physical Control. All host plants found to be infected with HLB will be removed and destroyed using mechanical means in order to stop the spread of the disease.
Residents of affected properties shall be invited to a public meeting where officials from CDFA, the Department of Pesticide Regulation, the Office of Environmental Health Hazard Assessment, and the county agricultural commissioner’s office shall be available 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 section 5771-5779 and 5421-5436. 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. Treatment information is posted at http://cdfa.ca.gov/plant/acp/treatment_maps.html.
Following the treatment, completion notices are left with the residents detailing precautions to take and post-harvest intervals applicable to the citrus fruit on the property.
Press releases, if issued, are prepared by the CDFA information officer and the county agricultural commissioner in close coordination with the program leader responsible for treatment. Either the county agricultural commissioner or the public information officer serves as the primary contact to the media.
Information concerning the HLB/ACP program shall be conveyed directly to local and State political representatives and authorities via letters, emails, and/or faxes.
Enclosed are the findings regarding the treatment plan, the November 22, 2017 UC and USDA briefing paper, a map of the treatment area, work plan, integrated pest management analysis of alternative treatment methods, and a pest profile.