Huanglongbing Discoveries in California

Recap of Huanglongbing Cases in California

News Release

Huanglongbing has now been confirmed in numerous communities in Los Angeles and Orange counties. These detections are disheartening, but the Citrus Pest & Disease Prevention Program, California Department of Food and Agriculture and county agricultural commissioners are taking aggressive steps to remove all diseased trees and educate homeowners about this critical threat to California citrus.

Here is a recap of the Huanglongbing activity in California to date:

Hacienda Heights:

HLB+ Trees = 2

HLB+ ACP = 1 (on the initial HLB detection site)

San Gabriel:

HLB+ Trees = 56

HLB+ ACP = 4 (on HLB+ tree sites)

Cerritos:

HLB+ Trees = 2

HLB+ ACP = 2 (1 on HLB+ tree site, 1 on a separate site)

Rosemead:

HLB+ Trees = 0

HLB+ ACP = 1

La Puente:

HLB+ Trees = 0

HLB+ ACP = 1

La Habra:

HLB+ Trees = 1

HLB+ ACP = 0

Anaheim:

HLB+ Trees = 11

HLB+ ACP = 8 (6 on HLB+ tree sites, 2 on separate sites)

Fullerton:

HLB+ Trees = HLB+ ACP = 1 (1 on HLB+ tree site)

In response to each and every HLB positive tree detection, CDFA conducts mandatory 800-meter response, which includes surveys and sampling of all host trees, treatments and removal of the confirmed HLB infected tree.

Nursery stock in quarantine areas is placed under USDA-approved screen facilities, where it is held and tested for two years, or it is destroyed. Outreach is done to homeowners and elected officials to educate them on the severity of the issue encourage them to help stop the spread of this devastating disease.

Patrick Cavanaugh2021-05-12T11:00:45-07:00June 26th, 2017|

Huanglongbing is causing concern in California

Increase of Huanglongbing in California Causes Concern

By Brian German, Associate Broadcaster

Southern California has seen a concerning increase in the amount of trees that are infected with Huanglongbing, or citrus greening disease. California Ag Today discussed the news with Beth Grafton-Cardwell, an IPM Specialist and Research Entomologist for the UC Riverside Entomology Department stationed in the San Joaquin Valley. She agreed that there is an increased concern surrounding HLB.

“It kind of exploded this fall, and it’s kind of continuing. And, that’s not unexpected. The Department of Food and Ag removes only the trees that are polymerase chain reaction – positive. And sometimes, it takes one to two years for a tree for you to be able to detect the bacteria using that method,” Grafton-Cardwell said.

Beth Grafton-Cardwell

There is no cure currently available for HLB, so once a tree is infected, it will eventually die. Researchers continue working to find a possible cure for HLB, or at the very least, a more effective means of diagnosing infected trees. “Most of the techniques that are going to help us cure or prevent the disease from being transmitted are five to ten years away. Yet, I think we’re going to see a rapid expansion of the disease in Southern California in this coming year,” Grafton-Cardwell said.

Early detection is one of the most important things. Grafton-Cardwell noted that many farmers are “helping to get the research accomplished and, for example, helping to get early detection techniques tested, and things like that so that we can try and stay on top of the disease.”

In California, production trees are not required to be screened, but many nurseries are now shifting towards putting all of their trees under screening in an effort to be more proactive in guarding against the spread of HLB.

Biological controls like Tamarixia are used as a means to reduce the number Asian citrus psyllids, which cause HLB, but that type of control method is not designed to completely eradicate insects.

“They’re starting to release the Tamarixia Wasps in Bakersfield. So we’re getting them up into the San Joaquin Valley so they can help out in those urban areas,” Grafton-Cardwell said.

Dogs are also used as a means to detect infected trees, but there is still a need for more effective techniques. “A large team of dogs can do maybe 1,000 acres a day, and we’ve got 300,000 acres of commercial citrus. So I think we need a multitude of techniques,” Grafton-Cardwell said.

Patrick Cavanaugh2021-05-12T11:01:59-07:00April 27th, 2017|

Citrus Referendum Coming Up

Citrus Growers to Vote on Referendum

News Release from Citrus Research Board

California citrus growers soon will receive a critical citrus referendum ballot from the California Department of Food and Agriculture (CDFA) asking them to vote on continuing the work of the Citrus Research Board (CRB) for the next five years.

The grower-funded and grower-directed CRB was chartered nearly 50 years ago to enable California citrus growers to sponsor and support needed research that industry members otherwise would be unable to individually fund or access on their own. The Board’s mission is to ensure a sustainable California citrus industry for the benefit of growers by prioritizing, investing in and promoting sound science.

Some key areas funded include general production research, a variety improvement research program, a quality assurance program on agricultural chemical residues, and pest and disease control activities. Currently, disease control is crucially important.

The California citrus industry is now in the fight of its life to prevent the spread of the devastating disease huanglongbing (HLB) from California’s orchards.

HLB already has decimated most other major citrus growing regions, including Florida.

In California, HLB so far only has been found in 40 residential trees in Los Angeles; however, unless researchers are able to find a solution, HLB could gain a foothold in the state’s commercial groves. Currently, the CRB is dedicating its primary research efforts to controlling the spread of HLB and eradicating the disease. The Board is beginning to see some promising results; but without the CRB, much valuable research will go unfunded.

“We urge all citrus growers to vote when they receive their ballots from the CDFA,” CRB President Gary Schulz said. “Citrus is important to our state’s economy, employment, health and positive identity. We are proud to proactively protect and sustain the world’s largest fresh citrus market. The work that our researchers are conducting is vital to sustaining the California citrus industry and ensuring its continued success.”

The CRB administers the California Citrus Research Program, the grower funded and grower-directed program established in 1968 under the California Marketing Act as the mechanism enabling the State’s citrus producers to sponsor and support needed research. More information about the Citrus Research Board may be found at www.citrusresearch.org.

Patrick Cavanaugh2021-05-12T11:01:59-07:00March 30th, 2017|

HLB Detected Again in San Gabriel

46 HLB Positive Trees in California

News Release from Citrus Insider

The California Department of Food and Agriculture crews conducting intensive, risk-based surveys detected eight citrus trees confirmed to be infected with Huanglongbing. All trees were in the core area of San Gabriel where HLB has previously been detected. This brings the total number of HLB-positive trees in California to 46.

CDFA routinely conducts HLB surveys throughout the state based on a risk model that considers factors that may make an area more likely to have a presence of the disease. CDFA has further fine-tuned this approach by increasing the number of samples pulled from citrus trees that are considered high risk. This strategic approach – developed by the CDFA lead diagnostician with input from the Citrus Pest & Disease Prevention Program and leading scientific researchers – has helped pinpoint infected trees.

State and local crews are building relationships with residents in the area, which not only helps gain access to properties, but also results in swift removal of trees identified as having HLB. While removal of diseased trees is mandatory, positive homeowner relationships encourage cooperation. Of the eight trees recently detected, seven have already been removed or been scheduled for removal by CDFA. Crews are contacting the property owner of the remaining citrus tree Tuesday, March 28, and will pursue quick removal.

In 2016, CDFA collected nearly 50,000 plant samples and nearly 80,000 Asian citrus psyllid samples to test for HLB. Since sample collection began in 2008, more than 400,000 plant and psyllid samples have been collected and processed. This diligent work has contributed to quick detection and eradication of diseased trees.

As a part of the Citrus Pest & Disease Prevention Program, CDFA will continue surveying and sampling the area for HLB and keep the industry abreast of finds as they occur.

Patrick Cavanaugh2021-05-12T11:05:17-07:00March 29th, 2017|

Citrus Trucks Will be Tarped

Tarped Citrus Trucks Will Fight ACP

By Melissa Moe, Associate Editor

In the ongoing battle against Asian Citrus Psyllids, an insect that is known to vector the fatal Huanglongbing disease in citrus, the California Department of Food & Agriculture has issued a new regulation to require trucks to be tarped when moving citrus. This regulation will be phased in and permit holders will be notified by CDFA.

Joel Nelsen, president of the California Citrus Mutual, explained that the regulation will prevent the spread of this vector-transmitted pathogen. “What we discovered is that psyllids were flying towards fruit sitting in trucks and bins as they were being transited from Southern California to the San Joaquin Valley, because of the aromas that the fruit gives off,” he said.

Fruit is not considered to be a vector of Huanglongbing since ACP can only vector the disease through leaves and twigs. However, these pests are catching rides on trucks all over the state on the fruit that was considered to be relatively safe.

“What happens is the Asian Citrus Psyllid is attracted to the aroma coming off of the orange, and it flies towards it thinking it’s going to find a food source,” Nelsen said. “Well, it rides around on the orange for a couple of hours, until it figures out that there’s no green waste or twigs attached to that fruit, and then it flies off.”

Fruit that is being transported from Bakersfield to Fresno could be taking these hitchhiking pests anywhere along Highway 99. While on this joyride, they could go up and down 5, across 126, or across 10 from Southern California into the San Joaquin Valley. News of new ACP finds have been right along these traveling corridors.

“We discovered that we may be part of the problem in helping Asian Citrus Psyllids spread, or have a hitchhiker role,” Nelsen said. “We made that determination as a result of some research done by the University of California. We ended up talking to growers at seven different grower meetings; several hundred in total were participating in the discussions. We all came to the conclusion that it’s going to cost us some money now, but it’s better than costing us the industry later.”

Patrick Cavanaugh2021-05-12T11:00:46-07:00January 9th, 2017|

Improved Huanglongbing Detection in Citrus Trees

Projects Underway for Better Huanglongbing Detection in Infected Trees

By Patrick Cavanaugh, Farm News Director

The big problem with Huanglongbing Disease (HLB), also known as citrus greening, is that an infected tree, despite having no visual symptoms, could quietly be a massive reservoir of HLB. The main vector, the Asian Citrus Psyllid (ACP), could easily pick up HLB from that tree and spread the disease throughout the orchard.

Currently, the main push to contain the possible spread of HLB is by controlling ACP. Yellow sticky traps are positioned near every commercial orchard in California, as well as near non-commercial trees in neighborhoods. Finding a psyllid on a trap triggers mandatory spray programs to help eliminate all psyllids in the area.

Neil McRoberts, associate professor of plant pathology, UC Davis

“Yes, one of the most critical questions in managing in HLB is the trees can be infected for a long time before you can visually see the ACP there,” said Neil McRoberts, an associate professor of plant pathology, University of California, Davis.

“There is a group of scientists, funded by the Citrus Research Board of California (CRB), working on different early detection methods. Those are methods where you would be able to tell the tree was infected before you could see the tree is infected,” said McRoberts.

The CRB funded field trials in Texas over the last few years that have narrowed the field of competitors to two or three techniques. The CRB will continue to fund the two leading contenders in that race to determine the leading early detection technology.

In the first technique, researchers analyzed all the microbes that live on a non-infected leaf surface and studied how that profile of microbes changes when the tree gets infected. Detecting a change in microbe profile could indicate the tree is not as healthy as it should be.

“Researchers take the microbes that live on an infected tree, extract the DNA from those microbes and run the DNA through a sequencer. The sequencer identifies which types of microbes are there,” he said.

McRoberts said sampling for microbes is easy. Researchers use an industrial-sized swab on the leaf surface. “You literally clean the leaf surface with the swab until it’s squeaky clean, put that swab in a bottle and send it to a lab. When it gets to the lab, they extract the DNA out of it and the rest of the process happens from there.

A female Tamarixia radiata laying egg on an ACP nymph. (Photo by J. Lotz). Courtesy of Citrus Research Board

In selecting which trees should undergo microbe swabbing, McRoberts noted that the ACPs tend to attack the groves from the outer edges, inwards. “At different times of the day, the light will be on different edges of the grove depending on where the sun is and how warm it is. You can target your sampling towards the places where you’re more likely to find it, but still, finding those initial little infections is tough.”

The second method is a technique called metabolic profiling. A newly infected tree starts to produce different proteins and other chemicals in response.

Still another research strategy is analyzing things that stay in the tissue. “There’s a change in the profile of metabolites in the tree. If you run those metabolites through a mass spectrometer, the mass spectrometer will spit out a profile. You can tell the difference between a healthy profile and an infected profile,” McRoberts said.

“This is how the dogs come into the picture. Everybody knows that citrus has an odor. When the trees are infected, the profile of the chemicals and the composition of that odor change. We can’t smell it, but a very sensitive electronic detector device can sometimes pick it up. Remarkably, dogs can pick it up. We think that’s what happening with the canine detectors; they’re picking up some change in the smell of the trees.”

McRoberts said that dogs are amazingly accurate in detecting trees with HLB disease. “The best that we can tell from the trials involving dogs, the false positive rate is less than 1 in 1,000. I’m very confident with the detector dogs,” McRoberts said.

Featured photo: Adult Asian citrus psyllid (Photo by J. Lewis). Courtesy of Citrus Research Board

Citrus Research Board of California (CRB)

UC Davis Department of Plant Pathology

California Ag Today2021-05-12T11:02:00-07:00December 2nd, 2016|

Gary Schulz Gives California Citrus ACP and HLB Update

California Citrus ACP and HLB Update from Gary Schulz

By Brian German, Associate Broadcaster

The Citrus Research Board (CRB) recently held their annual California Citrus Conference in Exeter, bringing together a variety of guest speakers and research presentations. The Conference focused on pressing Asian Citrus Psyllid (ACP) and Huanglongbing (HLB) issues, along with political action updates and current projects that are important to the citrus industry. Gary Schulz, president of the CRB, said “We have a 21-member board and we’ve been planning this event for the last 12 months. It’s been 4 years since we held the last conference,” noted Schulz.

Gary Schulz, president, Citrus Research Board

The CRB is responsible for overseeing the California Citrus Research Program (CCRP), a grower-funded and grower-directed program created in 1968 under the California Marketing Act. The CCRP’s purpose to enable California’s citrus producers to sponsor and support research that furthers the overall industry. Therefore, close to 70 percent of the CRB’s overall budget is allocated to research.

Schulz said the Conference “was a great, great day to have a good update on some of the dollars the Citrus Research Board has been spending on the growers’ behalf on research.” Schulz explained HLB represents the single greatest threat that citrus growers have faced worldwide.

For the past seven years, the USDA and Congress have allocated between $10 and $12 million dollars annually for ACP and HLB research operations. Advocacy groups and other supportive ag organizations have contributed the difference to reach an annual ACP and HLB research budget of close to $90 million dollars a year. We fund a lot of UC Riverside and USDA agricultural research, service researchers, plus research at UC Davis and the University of Arizona,” Schulz noted.

Schulz, who has many years of experience in California agriculture, having served as general manager of the Raisin Administrative Committee and CEO of the California Raisin Marketing Board, stated that CRB has a great working relationship with California Citrus Mutual (CCM). “Joel Nelson and CCM have worked very hard with the packers to assess themselves, put together a private foundation, and work with the university,” Schulz said.

Featured Photo: Adult Asian Citrus Psyllid (Source: The Citrus Pest & Disease Prevention Program)

Resources

California Marketing Act

Citrus Research Board (CRB)

California Citrus Mutual

California Ag Today2021-05-12T11:05:44-07:00November 18th, 2016|

US Citrus Industry Working Together on ACP, HLB Funding

Critical ACP, HLB Funding Comes Only After Industry Helps Itself

By Patrick Cavanaugh, Farm News Director

State Citrus Mutuals in California, Texas and Florida are diligently working in Washington, D.C., for $10 to 12 million in annual funding to help their citrus regions fight Asian Citrus Psyllid (ACP) infestation and Huanglongbing (HLB), the disease that ACPs vector.

The three Citrus Mutuals have collaborated well for the half dozen years of the American ACP invasion. Initially, the Florida Citrus Mutual team developed the Citrus Health Response Program (CHRP),” said Joel Nelsen, president of California Citrus Mutual.

Joel Nelsen, president of California Citrus Mutual

“They initiated it at a very minor funding level. However we sat down with them and said, ‘Look, this is an opportunity to ensure that all of the U.S. citrus industry can work together to protect itself from Huanglongbing.’ They were gracious enough to say okay. We exerted our leadership because we had people in positions in Washington who could be very beneficial to this,” Nelsen said.

“Initially it was a Florida/California effort. We said we need to double the size of the CHRP program and allocate more dollars to California, some to Texas, and some to Arizona. Now everybody is participating to the extent that they can. Today, it is still a Florida/California effort and a Florida/California-run program in partnership with USDA.

Nelsen said those involved are working hard to protect the citrus industry, and not just chasing a problem. Funding has been helpful to California. Only after the industry does all it can, will the state expect the federal government to help.

“It’s true for all three states’ industries,” Nelsen said. Unfortunately, Texas made a mistake. They did not have a policy in place to immediately remove an HLB-infected tree. As a result, they have an HLB infection spreading.”

“Texas is being adversely impacted on the dollar level. We don’t want to see that industry die, so there is a partnership that does exist on behalf of our colleagues,” Nelsen said. “We can’t afford to make mistakes like that.”

“In order to justify the continued progress of funding on an annual basis we are going to have to continue looking ahead, taking the steps necessary and doing what is needed to protect the citrus industry from the spread of Asian Citrus Psyllid and Huanglongbing.”

“We definitely have to show progress. We can’t ask homeowners to spray their trees if in fact we are not spraying ours. We can’t ask the federal government to continue helping us looking for ACPs if we are not willing to tarp our trucks to stop the spread of it. If we’re not willing to do a coordinated spray program then why should the government help us in finding HLB? If we are allowing snake oil merchants to conduct research projects, why should the federal government fund those?

California Ag Today2021-05-12T11:05:44-07:00November 9th, 2016|

ACP Spread in Bakersfield Area, Ingenious Research Proceeds

Ingenious Research Effort to Fight ACP Spread with Natural Predators

By Joanne Lui, Associate Editor

Beth Grafton-Cardwell, Cooperative Extension specialist, University of California, Riverside Department of Entomology

As we have reported in-depth before on California Ag Today, the Asian Citrus Psyllid (ACP) is a tiny, mottled brown insect that poses an ever-increasing threat to the state’s robust citrus industry, as well as to residential citrus trees. The pest can spread a bacterium known as Huanglongbing (HLP) that is fatal to citrus trees. The disease has nearly shut down Florida’s citrus industry.

Beth Grafton-Cardwell, cooperative extension specialist in integrated pest management, UC Riverside Department of Entomology, explained the significance of the recent ACP spread to Bakersfield. “That is really problematic because it’s mostly in the urban areas. It’s very difficult to find, to control and to stop that spread. It’s going to move out from that region into the local citrus orchards, and so there are lots of meetings and discussions right now to mobilize growers to get treatments to help protect their citrus orchards against the psyllid.”

#CitrusMatters

To contain the ACP problem, Grafton-Cardwell stated, “There are traps everywhere, but the traps are not terribly efficient. So, we really need to carefully examine groves and flush [new leaf growth] for the nymph form,” she said.

According to Agriculture and Natural Resources, University of California’s Statewide Integrated Pest Management Program:

Adults typically live one to two months. Females lay tiny yellow-orange almond-shaped eggs in the folds of the newly developing “feather flush” leaves of citrus. Each female can lay several hundred eggs during her lifespan.

ACP (Source: ACP UC IPM)

The eggs hatch into nymphs that are wingless, flattened, yellow or orange to brownish, and 1/100 to 1/14 inch long. Nymphs molt four times, increasing in size with each nymphal stage (instar), before maturing into adult psyllids. The nymphs can feed only on soft, young leaf tissue and are found on immature leaves and stems of flush growth on citrus.

The nymphs remove sap from plant tissue when they feed and excrete a large quantity of sugary liquid (honeydew). Each nymph also produces a waxy tubule from its rear end to help clear the sugary waste product away from its body. The tubule’s shape—a curly tube with a bulb at the end—is unique to the Asian citrus psyllid and can be used to identify the insect.

Grafton-Cardwell and other experts are concerned because once the ACP becomes established in urban areas, it is difficult to eradicate. “It starts spreading into the commercial citrus, and we’re off and running,” she commented.

In a ingenious effort to control the spread of the psyllid, trained teams of entomologists have imported Tamarixia radiata, a tiny wasp that naturally preys on ACP, from Pakistan to research and release in California. A cooperative effort of the University of California Riverside, Citrus Research Board, United States Department of Agriculture and California Department of Food and Agriculture, researchers are also exploring the effectiveness of another beneficial insect called Diaphorencyrtus aligarhensis to assist Tamarixia with control of the Asian citrus psyllid. To see where Tamarixia and Diaphorencyrtus have been released, visit this University of California’s website map at, “Distribution of ACP, HLB and Parasites in California,” and turn on the parasite layers.
Grafton-Cardwell said, “They’re going to inundate that area,” with natural ACP predators, “so hopefully that will push back a little bit.”

California Ag Today2021-05-12T11:05:46-07:00October 10th, 2016|

Breaking News: Cal Poly Opens New Greenhouse and Insect Rearing Facility

New Greenhouse Facility Opens to Save Citrus from Psyllids that Vector HLB

Facility to Rear Tamarixia Radiata, Natural ACP Predator

By Patrick Cavanaugh, Farm News Director

Scores of citrus industry leaders, citrus growers, scientists and CDFA officials attended the ribbon cutting event TODAY at the opening of a new greenhouse on the Cal Poly Pomona campus to rear Tamarixia radiata, a tiny parasitic wasp imported from Pakistan because it is an Asian Citrus Psyllid (ACP) nymph predator. ACP, in turn, is a serious nonnative citrus pest that can vector Huanglongbing (HLB)—a deadly citrus disease also known as Citrus Greening—that has devastated the powerhouse citrus

industry in Florida, threatens to ruin additional citrus economies, and is the biggest threat the California citrus industry has ever faced.

According to the United States Department of Agriculture Animal and Plant Health Inspection Service (USDA-APHIS), infected citrus trees “produce fruits that are green, misshapen and bitter, unsuitable for sale as fresh fruit or for juice. Most infected trees die within a few years.” ACPs have been detected in Alabama, American Samoa, Arizona, California, Florida, Georgia, Guam, Hawaii, Louisiana, Mississippi, Northern Mariana Islands, Puerto Rico, South Carolina, Texas and the U.S. Virgin Islands. Of those locations, the HLB disease has been detected in California, Florida, Georgia, Louisiana, Puerto Rico, South Carolina, Texas and the U.S. Virgin Islands.

ENTER: Tamarixia radiata

Use of the ACP predator, Tamarixia radiata as a biological control for ACP was discovered by Mark Hoddle, biological control specialist and principal investigator, UC Riverside ( UCR), Department of Entomology. The first release of Tamarixia was in December 2011 after USDA-APHIS cleared the natural enemy for release from the Quarantine Facility at UCR.

Mark Hoddle UC Riverside Department of Entomology

“Tamarixia can kill ACP nymphs in two different ways,” explained Nick Hill, a Tulare County citrus producer and Citrus Pest & Disease Prevention Program (CPDPC) chair. “The first is parasitism. In this instance, a female parasitoid lays an egg underneath a fourth or fifth instar—the larger and final developmental stage of the ACP nymph before becoming an adult—nymphs that are most preferred by Tamarixia for parasitism. When the egg hatches, the Tamarixia larva begins to feed on the under-surface of the ACP nymph. Eventually the larva completely excavates the body cavity of the ACP nymph and pupates inside the empty shell of its host.”

Hill explained the first releases of the tiny and harmless wasp will occur this fall in urban areas, “to help control ACP so that we do not have to do mitigations such as spraying in those areas. We hope to get to a point where we no longer need to go into people’s yards and ask if we can treat the trees.”

“The issue,” commented Valerie Melano, professor and chair, Cal Poly Pomona Plant Sciences and interim chair, Cal Poly Agribusiness & Food Industry Management/Agricultural Science, “is that we need to come up with the best possible ways to raise enough wasps for big releases to prey on ACP. We will have CDFA employees working in this green house, as well as student workers who have participated in our research program all along,” noted Melano.

Nick Hill, a Tulare County citrus producer and Citrus Pest & Disease Prevention Program (CPDPC) chair.

Hill added, “The idea is to get enough Tamarixia out there so they start reproducing themselves and they become self sufficient. This is tough to accomplish, but researchers think if they can get big numbers of the wasp into the urban areas, they can put a big dent in lowering the populations of ACP.”

Cal Poly Pomona Greenhouse

The new Cal Poly 5,040-square-foot research greenhouse, built in collaboration with Citrus Research Board and constructed through a $400,000 grant from the Citrus Pest & Disease Prevention Program, will house the second Tamarixia production program in California. CDFA’s Mount Roubideaux facility in Riverside houses current production. Both facilities will support the CPDPC biological control program that oversees releases in urban areas with high ACP populations.

The new greenhouse should produce a 1-1.5 million wasps. “It’s a very nice facility,” said Hill. “We are trying to boost the biological control program to produce four million Tamarixia a year.”

California Quarantine

The California Department of Food and Agriculture (CDFA) operates an extensive monitoring program to track the distribution of the insect and disease in both residential areas and commercial citrus groves. Results have determined quarantine zones, guided releases of biological control agents, and prioritized areas for a residential chemical control program. Nearly all of southern California is under quarantine for ACP, due to the fact that more than 15 residential trees have been discovered to be in infected with HLB.

The ACP quarantine in California includes parts of the following counties: Fresno, Kern, Kings, Madera, Monterey, San Benito, San Joaquin, San Luis Obispo, San Mateo, Santa Clara, and Stanislaus; and the following entire counties: Imperial, Los Angeles, Orange, Riverside, San Bernardino, San Diego, Santa Barbara, Tulare County, and Ventura.

Asian Citrus Psyllid Cooperative Program
California, Arizona, Baja California, and Sonora (USDA-APHIS). Visit our Citrus Diseases page to identify a plant infected by citrus greening, citrus canker, citrus black spot and sweet orange scab. If you detect an infected plant, report it immediately.

California Ag Today2021-05-12T11:05:51-07:00July 25th, 2016|