Huanglongbing, vectored by the Asian Citrus Psyllid, (ACP) is the dreaded disease that has nearly wiped out the Florida citrus industry and is a potential problem for citrus growers in California. California Ag Today recently met with Beth Grafton-Cardwell, a UC Cooperative Extension Specialist. She specializes in integrated pest management; she discussed new strategies for the control of HLB.
“We have been surveying grower orchards in southern California and following how pesticide sprays are working, and I’m going to make some new recommendations on how to handle the populations down there,” said Grafton-Cardwell, who is also the director of the Lindcove Research and Extension Center. “Some regions of Southern California are easier to control psyllids than others. The pesticide treatment is less intensive due to the desert climate. San Diego is one of the areas that is less intensive due to the drier trees making them more hardened off, with less new flushes, where ACP is attracted.”
“There are other areas of southern California where the trees flush continually, providing great places for the psyllids to lay eggs, and that is where treatments are going to have to intensify,” she explained.
Areas such as Ventura, Riverside, and San Bernardino have to increase their treatments in the fall for better control.
And researchers are currently studying new prevention and control methods.
“Texas A & M has been looking at erecting net-like borders around the orchards because the psyllid tends to go to the edges,” Grafton-Cardwell said.
They want to treat the netting with yellow strips of sticky paper that would attract and/or apply insecticides to kill the psyllid.
“Our research is showing that often the infestation starts on the borders. Growers may have to intensify the number of treatments, but they don’t have to treat the entire orchard,” Grafton-Cardwell said. “Growers might be able to fight the psyllid with only treating the trees on the outer edges.”
Intense Inspections of Urban Citrus Trees Continue
By Patrick Cavanaugh, Editor
Joel Nelsen is president and CEO of California Citrus Mutual, based in Exeter. He told California Ag Today recently that there is an “active plan to look for trees harboring Asian Citrus Psyllids (ACP) infected Huanglongbing (HLB) trees in urban areas because we’re looking for nobody else across this country, let alone in the southern hemisphere, to look for infected trees in the urban area. Mexico and Brazil didn’t do it. We’re doing it.”
The hope is that they find HLB and stop it there.
“Commercial growers are under tight testing programs to combat the Asian Citrus Psyllid. As far as it relates to commercial growers, we’re doing enough trapping that we’re not finding what we call hot spots of Asian Citrus Psyllids,” Nelsen said. “Secondarily and most importantly, we have a very strict clonal protection program, so growers are only allowed to access trees after they’ve gone through a rigorous testing program at both the nursery and the rootstock from the university.”
Nelsen said that the chances of a grower introducing the insect into an area is rather slim; it’s more often likely that the disease will be introduced to a grove.
Testing is random and more lab space is needed.
“Most of it’s been random because it is an intensive program. We’re analyzing roughly 20,000 leaves and twigs every month,” Nelsen explained. “We’re analyzing several thousand ACP every month. In fact, our lab capacity is capped, and one of the discussions that we’re having is to identify what labs can do what and whether or not we need to expand the number of labs doing business.”
“So we are looking at additional lab space, and in fact, we have already contracted with the University of Arizona Lab in Tucson and maybe we’ll consider using private labs to do the initial work,” Nelsen said. “Now, they’re not going to be able to confirm whether or not an ACP is there, but they go in and evaluate that twig or green waste waste and if in fact there is a suspicion, then you send in the California Department of Food and Agriculture folks.”
Joel Nelsen, president and CEO of the California Citrus Mutual based in Exeter, spoke to California Ag Today about a recent trip to UC Riverside to discuss the Citrus Health Response Program and huanglongbing disease.
“For the last several years, the federal government and the California citrus industry had a wonderful partnership with some ideas, some regulation, and most importantly, with some funds,” Nelsen said. “So periodically, USDA comes to do an audit as to what we’re doing, how we’re doing it, and whether or not there needs to be some reevaluation.”
“The Citrus Health Response Program is the program we call a CHRP for a two-day evaluation. You had scientists and regulators from USDA; you had regulators from CDFA, along with a few scientists,” Nelsen explained.
“You had that entire stakeholder group and members from the scientific community and UC Riverside to evaluate what we’re doing and why, but eventually we did achieve one objective and that’s coming up with several action steps that we need to do as an industry in partnership with government,” he said.
The concern of Huanglongbing disease was discussed and game plans were presented.
“What was interesting is this was a friendly audit. They weren’t interested in taking money away, they weren’t interested in determining if we’re using dollars appropriately, but they wanted us to talk about why we were still spraying in the urban environment for the Asian Citrus Psyllid, which vectors Huanglongbing,” Nelsen said.
“They wanted us to talk about whether or not growers were doing what they were supposed to be doing and of course, they are doing what they need to do to keep the deadly disease out of commercial citrus orchards,” Nelsen said.
Gary Schulz, President of the Citrus Research Board in Visalia, said the pest pressure in citrus comes down to three problems.
“You know, there’s three really. There’s Huanglongbing, Huanglongbing, and Huanglongbing, (HLB)” Schulz said at the recent California Citrus Conference in Visalia. “When I moved to California in 1990, I had an old-timer that was on my board. He said, ‘You know, in California, we have three major challenges: water, water, and water.’ Well, in the citrus research for pests and diseases, it’s really Huanglongbing.”
“If we’re talking about red scale or Phytophthora or lemon fruit drop, those are important challenges, but if HLB begins infecting our commercial groves and spreads as rapidly as it can without our attention and treatment or tree removal, the rest are moot,” Schulz said.
He discussed his hope for the future of the California citrus industry.
“I hope that in five years, we’ve solved HLB. That’s my personal goal. Somebody’s got to put the stake in the ground and put a date out there,” he noted.
Schulz said that Citrus Research Board has got a number of research programs that are all working side by side to find that solution, turn that key, and make that happen.
“It may be more than just one solution. We have a researcher at Washington State University in Pullman for example. They’ve earned a research grant from the USDA because of the creativity in putting their work team together and the fact that they bring a whole new fresh approach and fresh thought process to how to culture the bacteria that causes HLB disease. That’s huge in the science community and has never been done before,” Schulz said.
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.
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.
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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.
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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.
President-Elect Trump May Help Make California Agriculture Great Again!
By Patrick Cavanaugh, Farm News Director
The election of Donald J. Trump as the 45th President of the United States may prove very significant for California. He and his future administration may be able to make sense of the devastating water deliveries diverted from California farms to protect fish species that may already have become extinct, in order to comply with the Endangered Species Act.
Joel Nelsen, president, California Citrus Mutual and a leader in California agriculture, is encouraged by the election results. “You know, the Donald Trump election was a bit of a surprise to me. You can always hope, but the numbers did not look that good. Now that he is our president-elect, I think we can be somewhat optimistic about the next Congress and this next administration,” Nelsen said.
Nelsen said the optimism is going to be on several fronts. “One, I think we have an opportunity now to move water legislation that contains real storage and creates water for a bigger population in California,” he said.
“We also have an opportunity to slow down a rogue agency—which I would call Environmental Protection Agency (EPA)—and their activity specific to crop protection tools. We can get an effort going to modernize the Endangered Species Act. Nobody wants to eliminate species, but let’s face it, when that was first signed and passed, it was two generations ago. I think we need to take another look at that,” he said.
Nelsen noted there are some opportunities on the horizon. He hopes the upcoming Congress and new presidential administration will generate some positive activity for the California agriculture industry .
Nelsen and other California ag leaders will soon return to Washington to make sure things are getting done. “A couple of us are going back next week for the lame-duck session because we are hoping Congress will pass a budget that will fund the Asian Citrus Psyllid and Huanlongbing program,” he said. “There is no money for it in the USDA budget. As a result, the support at the federal level is less than what it could be or should be.”
“Because the current administration is going to be in office until January 19, 2017, the activists have until then to get things moving in a direction that cannot be stopped from their perspective. I don’t think these next two months will necessarily be quiet.”
“We must have a mindset that others will attempt to do what they think cannot be done. It will be up to many of us in leadership positions to ensure that there’s still a balanced approach with this administration before the next one comes in,” Nelsen said.
Authorities Need to Monitor ACP Detection, Confronted With Impatient Homeowners
by Patrick Cavanaugh, Farm Director
Joel Nelsen, the president of the Exeter-based California Citrus Mutual noted that most homeowners do not realize how intensive it is for authorities to monitor traps for the Asian Citrus psyllid (ACP) at their homes.
“Most people don’t realize how intrusive this process is,” said Nelsen. “You’ve got a member of the County Ag Commissioner’s office driving down a street. He sees a citrus tree in a front yard, or he can see it’s tall enough in the back. He knocks on the door. The homeowner’s not home, so he has to come back.”
“Later, he comes back to the home and again, knocks on the door and finds that the homeowner is home. He says, ‘Can I put a trap out here to find out if you’ve got the Asian citrus psyllid?’ The homeowner hopefully says, ‘Yes.’ He comes back in two weeks. He looks at the trap. There’s no ACP. He comes back two weeks later, and if the homeowner is home, he looks at the trap,” Nelsen explained.
“It’s a constant bother to that homeowner,” Nelsen said. “Eventually, they find more than one ACP. Then the inspector says: ‘Can I spray a crop protection material on your tree and kill the Asian citrus psyllid?’”
“Hopefully the homeowner says, ‘Yes,’” said Nelsen.
Nelsen noted that the inspector visited five times already within a two month period, and now he needs to do inspect elsewhere, so having that homeowner be amenable to that much intrusiveness is a significant goal.
Nelsen noted, “The consumer education program that forms the partnership between us and them, from our perspective, is vitally important so the consumers understand what Huanglongbing (HLB)—the fatal citrus disease carried by ACP—is”.
“Then when you find Huanglongbing (HLB),” said Nelsen, “and hopefully it’s very minimal, that homeowner is more likely to agree that the tree must be removed. Fortunately, everybody has said: ‘Yes.’”
USDA Targets Citrus Greening with Promising Tools and Long Term Solutions
Agriculture Secretary Tom Vilsack announced $30 million in funding TODAY for 22 projects to help citrus producers combat Huanglongbing (HLB), also known as citrus greening, a devastating citrus disease that threatens U.S. citrus production. The money will fund promising projects that could offer near-term solutions as well as research funding that may develop long-terms solutions. The promising near-term tools and solutions are funded through the HLB Multiagency Coordination Group while the research projects are funded through the Specialty Crop Research Initiative Citrus Disease Research and Education (CDRE) program, which is made available through the Agricultural Act of 2014 (Farm Bill).
“Our HLB Multi-Agency Coordination Group has worked closely with the citrus industry to select and fund projects that we think will make a real difference for growers against HLB,” said Vilsack. “Funding these projects through cooperative agreements puts us one step closer to putting real tools to fight this disease into the hands of citrus growers.” Vilsack continued, “Through the CDRE research we are announcing today, we are also investing in long-term solutions to diseases that threaten the long-term survival of the citrus industry.”
USDA’s HLB Multi-Agency Coordination Group funded fifteen projects that support thermotherapy, best management practices, early detection, and pest control efforts for a total of more than $7 million. All of them are designed to provide near-term tools and solutions to Agriculture Secretary Tom Vilsack announced $30 million in funding TODAY for 22 projects to help citrus producers combat Huanglongbing (HLB), also known as citrus greening, a devastating citrus disease that threatens U.S. citrus production. the citrus industry fight HLB. The projects include:
Two projects to provide improved delivery of thermotherapy to HLB infected trees, a promising treatment that has shown to help infected trees regain productivity after treatment. One of these projects will test thermotherapy on a grove-wide scale. since studies have shown heating a tree to 120 degrees for approximately 48 hours can kill the HLB bacterium in the upper part of the tree, allowing the tree to regain productivity. This funding will address the challenge of identifying a quick and practical way for growers to use the technology on a large scale.
Six projects to provide citrus producers with best management practices in Florida citrus groves.
One project will focus on lowering the pH of the irrigation water and soil to strengthen the root systems of citrus trees to help them better tolerate HLB infection.
Three projects will support different combinations of integrated management approaches for sustaining production in trees in different stages of infection.
Two projects will test strategies for preventing tree death due to HLB infection. One of those will field test rootstocks that have shown ability to tolerate HLB infection. The other will use technologies to rapidly propagate the tolerant material for field use by the industry.
Three projects to increase early detection of HLB.
One project will train dogs to detect HLB infected trees. Detector dogs have proven to be highly adept at detecting citrus canker and early results suggest they will be an effective early detection tool for HLB.
One project will develop a root sampling and testing strategy.
One project will compare several promising early detection tests.
Four projects to provide tools to kill the Asian citrus psyllid (ACP), the vector of HLB.
One will produce and release the insect Diaphorencyrtus aligarhensis as a second biological control agent in California.
One project will use a biocontrol fungus to kill ACP adults.
One project will use a trap to attract and kill ACP adults.
One project will increase the use of field cages for the production of the insect Tamarixia radiata in residential areas, especially those that are adjacent to commercial groves in Texas. Tamarixia has already proven to be an effective biological control agent for ACP. Using field cages will enable the wider use of this effective ACP control.
In addition to these projects, USDA’s National Institute of Food and Agriculture funded more than $23 million dollars for research and education project to find lasting solutions to citrus greening disease. Examples of funded projects include developing HLB-resistant citrus cultivars, the development of field detection system for HLB, using heat as a treatment for prolonging productivity in infected citrus trees, creating a new antimicrobial treatment, among others. A fact sheet with a complete list of awardees and project descriptions is available on the USDA website.
Fiscal year 2014 grants have been awarded to two California universities, University of California, Davis, $4.6M and University of California, Riverside, $1.7M. The University of Florida, Gainesville and Kansas State University, Manhattan, are also receiving research awards.
CDRE is a supplement to the Specialty Crop Research Initiative (SCRI). The focus of this year’s funding was specifically on citrus greening disease. Because there are wide differences in the occurrence and progression of HLB among the states, there were regional as well as national priorities for CDRE. These priorities, recommended by the Citrus Disease Subcommittee, fall within four categories: 1) priorities that deal with the pathogen; 2) those that deal with the insect vector; 3) those that deal with citrus orchard production systems; and 4) those that deal with non-agricultural citrus tree owners.
One subcommittee member is Justin D. Brown, Vice President and General Manager, D Bar J Orchards, Inc. in Orange Grove, California.
The Farm Bill builds on historic economic gains in rural America over the past six years, while achieving meaningful reform and billions of dollars in savings for taxpayers. Since enactment, USDA has made significant progress to implement each provision of this critical legislation, including providing disaster relief to farmers and ranchers; strengthening risk management tools; expanding access to rural credit; funding critical research; establishing innovative public-private conservation partnerships; developing new markets for rural-made products; and investing in infrastructure, housing and community facilities to help improve quality of life in rural America. For more information, visit www.usda.gov/farmbill.