Big Research Funds Continue to Fight Huanglongbing Disease

$7 Million Multi-State Research Project Targets Citrus Threat HLB

UC ANR part of team led by Texas A&M AgriLife combating Huanglongbing disease

By Mike Hsu UCANR Senior Public Information Representative

Citrus greening, or huanglongbing disease (HLB), is the most devastating disease for orange and grapefruit trees in the U.S. Prevention and treatment methods have proven elusive, and a definitive cure does not exist.

Since HLB was detected in Florida in 2005, Florida’s citrus production has fallen by 80%. Although there have been no HLB positive trees detected in commercial groves in California, more than 2,700 HLB positive trees have been detected on residential properties in the greater Los Angeles region.

“It is likely only a matter of time when the disease will spread to commercial fields, so our strategy in California is to try to eradicate the insect vector of the disease, Asian citrus psyllid,” said Greg Douhan, University of California Cooperative Extension citrus advisor for Tulare, Fresno and Madera counties.

Now, a public-private collaborative effort across Texas, California, Florida and Indiana will draw on prior successes in research and innovation to advance new, environmentally friendly and commercially viable control strategies for huanglongbing.

Led by scientists from Texas A&M AgriLife Research, the team includes three UC Agriculture and Natural Resources experts: Douhan; Sonia Rios, UCCE subtropical horticulture advisor for Riverside and San Diego counties; and Ben Faber, UCCE advisor for Ventura, Santa Barbara and San Luis Obispo counties.

$7 million USDA project

The $7 million, four-year AgriLife Research project is part of an $11 million suite of grants from the U.S. Department of Agriculture National Institute of Food and Agriculture, NIFA, to combat HLB. The coordinated agricultural project is also a NIFA Center of Excellence.

“Through multistate, interdisciplinary collaborations among universities, regulatory affairs consultants, state and federal agencies, and the citrus industry, we will pursue advanced testing and commercialization of promising therapies and extend outcomes to stakeholders,” said lead investigator Kranthi Mandadi, an AgriLife Research scientist at Weslaco and associate professor in the Department of Plant Pathology and Microbiology at the Texas A&M College of Agriculture and Life Sciences.

The UC ANR members of this collaboration will be responsible for sharing findings from the research with local citrus growers across Southern California, the desert region, the coastal region and the San Joaquin Valley.

“In addition to the ground-breaking research that will be taking place, this project will also help us continue to generate awareness and outreach and share the advancements taking place in the research that is currently being done to help protect California’s citrus industry,” said Rios, the project’s lead principal investigator in California.

Citrus trees in Florida suffer from HLB infection

Other institutions on the team include Texas A&M University-Kingsville Citrus Center, University of Florida, Southern Gardens Citrus, Purdue University and USDA Agricultural Research Service.

“This collaboration is an inspiring example of how research, industry, extension and outreach can create solutions that benefit everyone,” said Patrick J. Stover, vice chancellor of Texas A&M AgriLife, dean of the Texas A&M College of Agriculture and Life Sciences and director of Texas A&M AgriLife Research.

HLB solutions must overcome known challenges

An effective HLB treatment must avoid numerous pitfalls, Mandadi explained.

One major problem is getting a treatment to the infected inner parts of the tree. The disease-causing bacteria only infect a network of cells called the phloem, which distributes nutrients throughout a tree. Starved of nutrients, infected trees bear low-quality fruits and have shortened lifespans.

Treatments must reach the phloem to kill the bacteria. So, spraying treatments on leaves has little chance of success because citrus leaves’ waxy coating usually prevents the treatments from penetrating.

Second, while the bacteria thrive in phloem, they do not grow in a petri dish. Until recently, scientists wishing to test treatments could only do so in living trees, in a slow and laborious process.

Third, orange and grapefruit trees are quite susceptible to the disease-causing bacteria and do not build immunity on their own. Strict quarantines are in place. Treatments must be tested in groves that are already infected.

Two types of potential HLB therapies will be tested using novel technologies

The teams will be working to advance two main types of treatment, employing technologies they’ve developed in the past to overcome the problems mentioned above.

First, a few years ago, Mandadi and his colleagues discovered a way to propagate the HLB-causing bacteria in the lab. This method involves growing the bacteria in tiny, root-like structures developed from infected trees. The team will use this so-called “hairy roots” method to screen treatments much faster than would be possible in citrus trees.

In these hairy roots, the team will test short chains of amino acids – peptides – that make spinach naturally resistant to HLB. After initial testing, the most promising spinach peptides will undergo testing in field trees. To get these peptides to the phloem of a tree, their gene sequences will be engineered into a special, benign citrus tristeza virus vector developed at the University of Florida. The citrus tristeza virus naturally resides in the phloem and can deliver the peptides where they can be effective.

“Even though a particular peptide may have efficacy in the lab, we won’t know if it will be expressed in sufficient levels in a tree and for enough time to kill the bacteria,” Mandadi said. “Viruses are smart, and sometimes they throw the peptide out. Field trials are crucial.”

The second type of treatment to undergo testing is synthetic or naturally occurring small molecules that may kill HLB-causing bacteria. Again, Mandadi’s team will screen the molecules in hairy roots. A multistate team will further test the efficacy of the most promising molecules by injecting them into trunks of infected trees in the field.

A feasible HLB treatment is effective and profitable

Another hurdle to overcome is ensuring that growers and consumers accept the products the team develops.

“We have to convince producers that the use of therapies is profitable and consumers that the fruit from treated trees would be safe to eat,” Mandadi said.

Therefore, a multistate economics and marketing team will conduct studies to determine the extent of economic benefits to citrus growers. In addition, a multistate extension and outreach team will use diverse outlets to disseminate project information to stakeholders. This team will also survey growers to gauge how likely they are to try the treatments.

“The research team will be informed by those surveys,” Mandadi said. “We will also engage a project advisory board of representatives from academia, universities, state and federal agencies, industry, and growers. While we are doing the science, the advisory board will provide guidance on both the technical and practical aspects of the project.”

Project team members:

—Kranthi Mandadi, Texas A&M AgriLife Research.

—Mike Irey, Southern Gardens Citrus, Florida.

—Choaa El-Mohtar, University of Florida Institute of Food and Agricultural Sciences, Citrus Research and Education Center.

—Ray Yokomi, USDA-Agricultural Research Service, Parlier, California.

—Ute Albrecht, University of Florida IFAS Southwest Florida Research and Education Center.

—Veronica Ancona, Texas A&M University-Kingsville Citrus Center.

—Freddy Ibanez-Carrasco, Texas A&M AgriLife Research, Department of Entomology, Weslaco.

—Sonia Irigoyen, AgriLife Research, Texas A&M AgriLife Research and Extension Center at Weslaco.

—Ariel Singerman, University of Florida IFAS Citrus Research and Education Center.

—Jinha Jung, Purdue University, Indiana.

—Juan Enciso, Texas A&M AgriLife Research, Department of Biological and Agricultural Engineering, Weslaco.

—Samuel Zapata, Texas A&M AgriLife Extension, Department of Agricultural Economics, Weslaco.

—Olufemi Alabi, Texas A&M AgriLife Extension, Department of Plant Pathology and Microbiology, Weslaco.

—Sonia Rios, University of California Cooperative Extension, Riverside and San Diego counties.

—Ben Faber, University of California Cooperative Extension, Ventura, Santa Barbara and San Luis Obispo counties.

—Greg Douhan, University of California Cooperative Extension, Tulare, Fresno and Madera counties.

California Ag Today2021-12-06T13:51:10-08:00December 6th, 2021|

San Bernardino County HLB Quarantine Boundaries May Expand

CDFA Proposes Expansion of HLB Quarantine Boundaries for San Bernardino County

Effective January 6, 2020, the Department is expanding the San Bernardino County Quarantine Boundary. A map of the proposed boundary can be found at https://www.cdfa.ca.gov/plant/hlb/regulation.html#maps.

Regulated articles and conditions for intrastate movement under the quarantine can be found at Title 3 California Code of Regulations (CCR) section 3439. Pursuant to Title 3 CCR section 3439 any interested party or local entity may appeal a quarantine area designation.

Additionally effective January 6, 2020, the Department is expanding the ACP Bulk Citrus Regional Quarantine Zone 6 boundary in the San Bernardino County, Montclair area to mirror the recent expansion of the HLB quarantine area. A map of the proposed boundary can be found at: www.cdfa.ca.gov/plant/go/acp-quarantine#maps

Regulated articles and conditions for intrastate movement under the quarantine can be found at Title 3 California Code of Regulations (CCR) section 3435. Pursuant to Title 3 CCR section 3435, any interested party or local entity may appeal a quarantine area designation.

Process to Appeal the Proposed Expanded/Changed Boundary

The appeal must be submitted to the Department in writing and supported by clear and convincing evidence. The appeal must be filed no later than ten (10) working days from the date of this notification. During the pending of the appeal, the designated Quarantine Boundary under appeal shall remain in effect.

Mail Appeals to:

CDFA – Pest Exclusion

1220 N Street

Sacramento, CA 95814

California Ag Today2021-05-12T11:00:35-07:00January 6th, 2020|

Volunteers Need for CDFA Citrus Pest Prevention

CDFA Announces Three Vacancies on the Citrus Pest and Disease Prevention Committee

The California Department of Food and Agriculture is announcing three vacancies on the Citrus Pest and Disease Prevention Committee. Committee member vacancies exist for one grower representative each from Tulare and Ventura Counties, and one citrus nursery representative from Southern California. Individuals interested in being considered for a committee appointment should send a brief resume by November 1, 2019 to the California Department of Food and Agriculture.

Asian Citrus Psyllid Evidence on New Growth (Source: California Ag Today)

The Committee advises the CDFA secretary on activities associated with the statewide citrus specific pest and disease work plan that includes but is not limited to outreach and education programs and programs for surveying, detecting, analyzing, and treating pests and diseases specific to citrus.

The members receive no compensation but are entitled to payment of necessary travel expenses in accordance with the rules of the Department of Personnel Administration.

Committee member vacancies exists for one grower representative each from Tulare and Ventura Counties, and one citrus nursery representative from Southern California. All three member terms expire on September 30, 2023. Applicants should have an interest in agriculture and citrus pest and disease prevention. Individuals interested in being considered for a committee appointment should send a brief resume by November 1, 2019 to the California Department of Food and Agriculture, Citrus Pest and Disease Prevention Division, 2800 Gateway Oaks Dr., Suite 200, Sacramento, California 95833, Attention: Victoria Hornbaker.

For additional information, contact: Victoria Hornbaker, Director, Citrus Pest and Disease Prevention Division at 916-654-0317, or e-mail victoria.hornbaker@cdfa.ca.gov.

California Ag Today2021-05-12T11:01:45-07:00October 30th, 2019|

Citrus Growers’ Response To Huanglongbing

Industry Committee Endorses Voluntary Best Practices

News Release

To provide California citrus growers with a strong toolbox of science-supported strategies and tactics to protect their orchards from Huanglongbing (HLB), the Citrus Pest & Disease Prevention Committee endorsed a set of best practices for growers to voluntarily employ in response to HLB in California.

Adult Asian citrus psyllid, Huanglongbing

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

The recommendations—which were developed based on a grower’s proximity to an HLB detection—represent the most effective tools known to the citrus industry at this time and are meant to supplement the California Department of Food and Agriculture’s required regulatory response. The best practices were developed by a task force consisting of growers from various regions across the state and scientists, all of whom were nominated by the Citrus Pest & Disease Prevention Committee.

Voluntary best practices were developed for growers in the four following scenarios:

Scenario 1: Orchards outside of an HLB quarantine area
Scenario 2: Orchards located between one and five miles of an HLB detection (within an HLB quarantine area)
Scenario 3: Orchards within one mile of an HLB detection but not known to be infected
Scenario 4: Orchards with HLB

The best practices vary in each scenario but all address: awareness, scouting for the Asian citrus psyllid, controlling Asian citrus psyllids with treatments, protecting young trees and replants, employing barriers or repellents, visually surveying for HLB, testing psyllid and plant material for HLB using a direct testing method like polymerase chain reaction (PCR), and tending to trees’ root health. The voluntary best practices in all four scenarios can be found at CitrusInsider.org.

While HLB has not yet been detected in a commercial grove in California, the disease continues to spread throughout residential communities of Los Angeles, Orange, and Riverside counties. HLB has infected more than 1,400 citrus trees, and 1,003 square miles are currently in an HLB quarantine area.

“Our state’s citrus industry has held the line against HLB since the first detection seven years ago. We should commend our efforts but must not forget the devastating impact HLB could have on our orchards and our livelihood,” said Jim Gorden, chair of the Citrus Pest & Disease Prevention Program and a citrus grower in Tulare County.

“We know the cost to manage the Asian citrus psyllid is far less than any potential costs or loss to the industry should HLB take hold throughout our state. These voluntary best practices are meant to serve as a box of tools so growers can use as many as are feasible for their operation in order to limit the spread of the psyllid and disease,” said Keith Watkins, chair of the task force that developed the best practices and vice president of farming at Bee Sweet Citrus.

California Ag Today2021-05-12T11:01:47-07:00July 3rd, 2019|

CA Citrus Growers Work Hard to Prevent HLB Devastation

Learning From the Florida Industry as to How Bad it Can Be

By Mikenzi Meyers, Associate Editor

The severe effects of the Huanglongbing (HLB) disease on Florida citrus is cause for California growers to take important preventative measures to ensure the safety of their trees. Keith Watkins, vice president of outside operations for Bee Sweet Citrus, has seen the damage firsthand and has been hard at work to protect his trees.

“I’ve been to Florida, and I’ve seen how devastating the disease can be,” he said. “We have to spend money now to basically prevent that from happening to us.”

There are currently around 1100 trees that have tested positive for HLB in the Orange County and Anaheim-Garden Grove areas, but they are mainly backyard citrus trees. Luckily, Watkins said that the disease has not yet been traced in commercial operations.

Keeping HLB out of commercial growth is the biggest challenge growers face. There is not yet a cure for the disease, but according to Watkins, growers can help prevent it from reaching their crops by staying on top of killing psyllids when spotted. “We have to stay diligent. Our future really is maintaining a psyllid free population,” he said.

California Ag Today2021-05-12T11:01:47-07:00June 4th, 2019|

CCM Statement on Chlorpyrifos Ban

Flawed Data Forcing Cancellation

News Release From California Citrus Mutual

Recently, the California Environmental Protection Agency (CalEPA) and the California Department of Pesticide Regulation (DPR) announced that they are going to begin the cancellation process of chlorpyrifos. The statement cites scientific findings that chlorpyrifos poses serious public health and environmental risks to vulnerable communities.

“The decision to ban chlorpyrifos is not surprising given the significant pressure from anti-pesticide groups, active legislative proposals, regulatory proceedings, and ongoing court battles,” said CCM President Casey Creamer. “However, this decision relies heavily on an evaluation that was significantly flawed and based upon unrealistic modeling scenarios that are not verifiable by actual results in DPR’s own air monitoring network.”

“California Citrus Mutual and our member growers stand by science that is sound, that properly evaluates risks and puts forward appropriate safeguards to protect ourselves, our employees, and our surrounding communities. We are committed to safe and effective use of chlorpyrifos and other crop protection tools.”

“The process for which this chemical was evaluated was purposely exaggerated to achieve the desired outcome and jeopardizes the scientific credibility of the Department of Pesticide Regulation. This decision sets a terrible precedent for future evaluations and creates a chilling effect on companies planning on making significant investments to bring new products to the market in California.”

“The citrus industry is fighting feverishly to protect itself from the deadly citrus disease, Huanglongbing,” Creamer continued. “In order to do so, we must have the necessary tools in the toolbox for an effective Integrated Pest Management program.”

“The once mighty citrus-producing state of Florida has lost 70% of its production due to this disease, which is expanding exponentially in residential citrus trees in Southern California at this very moment. While our commercial growers will remain vigilant, it is vital that our policymakers recognize the seriousness of the threat and ensure sound scientific procedures are followed.”

“California Citrus Mutual will continue to be actively engaged in the regulatory processes around the cancellation decision and will continue to explore all potential remedies to allow the safe and effective use of chlorpyrifos.”

California Ag Today2021-05-12T11:05:03-07:00May 14th, 2019|

Reducing ACP Spread In California

Beth Grafton-Cardwell: Spread of Disease Must Be Prevented

By Patrick Cavanaugh, Editor

Collaborative changes are being made to combat the Asian Citrus Psyllid (ACP). Beth Grafton-Cardwell is the director of Lindcove Research and Extension Center near Exeter, as well as a research entomologist with UC Riverside. She recently spoke at the 2019 Citrus Showcase in Visalia as a key speaker on the state of Huanglongbing (HLB) in California, with an overview of how to prevent ACP,—which vectors HLB, a fatal disease to citrus—from moving around the state.

“We were trying to communicate why we’ve made the changes we’ve made for the industry that has been a collaborative effort between CDFA, growers, and the university,” Grafton-Cardwell said. “We need better ways to prevent psyllids from moving around the state because they might have HLB in their bodies, and we’ve got to prevent the spread of the disease.”

Beth Grafton-Cardwell

The Florida citrus industry did not do a great job in containing the Psyllid, and now HLB is rampant in the state’s citrus industry, which has devastated the citrus economy there.

“Florida found that they did not do much to control psyllid movement, and they found that psyllids were moving in bulk citrus bins and retail nursery plants around the state, and within a concise amount of time, they spread the Psyllid and the disease everywhere,” Grafton-Cardwell said. “We’re trying to avoid that. We have 100% tarping of citrus truckloads. We have treatments that have to be done if growers want to move citrus between major zones in California, so that we can prevent that kind of movement.”

Conversations continue about quarantine areas in California to reduce spread.

“There’s been a lot of discussion regarding quarantines because it’s painful for some growers who have low Psyllid numbers to have to treat and to move their fruit to other zones.”

“There’s been a lot of questions. We did a lot of scientific analysis to look at impacts as well as numbers. It’s not just about psyllid numbers; it’s about their impact if growers were to move the disease into a high citrus growing region,” Grafton-Cardwell explained.

California Ag Today2021-05-12T11:01:48-07:00May 8th, 2019|

Fighting for Citrus Industry

Continuing to Fight For Citrus Industry’s Longevity Requires Teamwork

By Jim Gorden, Committee Chair, Citrus Pest and Disease Prevention

For more than two centuries, citrus has grown strong in California’s yards and groves—serving as a source of nourishment, income, and tradition for many different individuals—but the citrus industry is at risk due to Huanglongbing’s (HLB) growing presence in California.

Jim Gorden

In 2018, HLB was found in more than 600 residential citrus trees in Southern California, and despite the program’s thorough surveying efforts, HLB has not been found in a commercial grove, but we must continue to hold strong. It has never been more important for all of us— including the Citrus Pest & Disease Prevention Program (CPDPP), regulatory authorities, the citrus industry, the scientific community, and others—to work together to prevent the spread of the disease and save California’s citrus industry.

While much has changed since the citrus industry came together ten years ago to support the creation of the CPDPP, one constant remains: the program’s dedication to fighting HLB. This year, the Citrus Pest & Disease Prevention Committee (CPDPC) created a strategic plan for combatting HLB now and in the future. The plan identified five prioritized strategies to achieve CPDPP’s goals of keeping HLB out of commercial groves, limiting Asian citrus psyllid (ACP) movement in the state and fine-tuning the program. In addition, the program agreed to align its annual budget in support of the strategies, which can be viewed in this report.

With this plan comes additional responsibilities for all individuals involved. The CPDPC understands HLB isn’t the only issue posing a threat to your business and our industry – but it’s one we can’t ignore. This report highlights the many activities the program and our partners are doing across the state to protect commercial groves from HLB, but we are only as strong as our weakest link.

Looking forward, much is at stake for California citrus growers, packers and workers as the industry faces its biggest threat yet in HLB. I encourage you to connect with the program, your local pest control district, or task force, and follow best practices for managing the ACP and HLB. If we sit idle, hoping others will take action for our benefit, we are welcoming this devastating disease into our groves.

But, by working together, we can protect California’s commercial citrus industry from devastation—sustaining our livelihood and the legacy of California citrus.

For more information on the Citrus Pest & Disease Prevention Program Click here.

California Ag Today2021-05-12T11:01:49-07:00April 25th, 2019|

Quarantines in Place to Prevent ACP Spread

Quarantines Painful For Some Growers

By Mikenzi Meyers, Associate Editor

It’s been a tough road for citrus growers since the discovery of the Asian Citrus Psyllid (ACP) back in 2012. Those affected have been forced to quarantine their crops, a task that Beth Grafton-Cardwell, director of Lindcove Research Extension Center in Tulare and research entomologist with UC Riverdale, said can be difficult.

“There’s been a lot of discussion about the quarantines because they’ve been painful for some growers who have low psyllid numbers to have to treat them and move their fruit to other zones,” Cardwell explained.

Beth Grafton-Cardwell

The growing concerns have led to continuous research regarding whether or not the zones should be changed.

There have been more than 1,100 citrus trees that have tested positive for HLB. There have been more than 230 positive finds of the psyllid, and although this sounds like a big number, Cardwell said its actually normal due to how difficult the disease is to detect.

“We can’t tell that the tree is infected early on because a localized infection might be on one stem of the entire tree, and it might take a year before it moves throughout the tree,” she said.

Right now, quadrant sampling is being done, where four quadrants of the tree are sampled for the disease. Current samples are showing that one in four quadrants are coming back positive.

“It’s finding the trees that are infected that’s really difficult, and meanwhile, the psyllid is spreading, spreading, spreading the disease,” Cardwell said.

More information can be found at this link:

https://maps.cdfa.ca.gov/WeeklyACPMaps/HLBWeb/HLB_Treatments.pdf

California Ag Today2021-05-12T11:01:49-07:00April 5th, 2019|

CAPCA Gets to the Capitol To Work for PCAs

PCAs Are in Every Legislative District

By Jessica Theisman, Associate Editor

CAPCA has recently become more active in the capitol. Ruthann Anderson, CEO and president of California Association of Pest Control Advisors (CAPCA), said the association has PCAs in every legislative district all over the state of California.

“Whether it’s in turf and ornamental or in production agriculture, you know, we have a voice, and we have a lot of ability to influence some of the decisions or at least advise on some of the decisions that might be happening.,” she said.

Anderson said that CAPCA’s capitol visits have been positive.

“We’re on a first name basis with a lot more people than we have been,” she explained.

CAPCA is working with both urban and agricultural legislators.

“I am trying to prioritize both. I think that it wouldn’t be fair for us to neglect our local legislators just because we know that the urbans are a little bit more of our moderate Dems that we’re trying to pursue relationships with,” she said.

CAPCA would like to balance both and continue educating them on the field.

“Our Northern California Chapter is meeting with Senator Nielsen’s office from time to time, just letting them know exactly what’s happening in the field and making sure that they are in the loop,” Anderson said.

This way, if any questions arise, there is open communication between the office and the local CAPCA chapter.

“I know that they are asking a lot of questions about specific crop protection materials, and I think that is important for us to be able to tell the story,” Anderson said.

Sometimes, there is not an alternative, and CAPCA is there to explain.

“When controlling the Asian Citrus Psyllid that can spread the Huanglongbing disease in citrus, sometimes there is not an alternative; sometimes we’re quarantined and forced to do scheduled spraying. That is just a part of protecting the industry,” Anderson explained.

California Ag Today2021-05-12T11:01:50-07:00March 20th, 2019|