The Fight Against the Asian Citrus Psyllid

California Citrus Mutual on the Fight Against the Asian Citrus Psyllid and HLB

By Laurie Greene, Editor

On Saturday, June 4, 2016, Patrick Cavanaugh, California Ag Today’s farm news director, hosted iHeart Media’s Ag Life Weekend show on “Power Talk 96.7 FM Fresno and 1400 AM Visalia stations, sitting in for broadcaster Rich Rodriguez. Cavanaugh’s invited guests included Alyssa Houtby, director of public affairs, and Chris Stambach, director of industry relations for the Exeter-based California Citrus Mutual, to discuss the status of the state’s citrus industry amidst the ACP and HLB Infestation.Ag Life Weekend

The Asian Citrus Psyllid (ACP), certainly the number one pest for California citrus, can spread a bacterium known as Huanglongbing (HLB) that is fatal to citrus trees. As of 2016, 22 trees in the state have been infected with the fatal disease and had to be destroyed. The entire citrus industry of California has been and continues to be concerned that the ACP could take down the citrus industry, as it has in Florida.

Alyssa Houtby explained that the fight against ACP in California “is going well, we hope. The Florida citrus industry has been completely decimated by HLB; an estimated 90 percent of their acreage is infested with this disease.”

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

“Here in California,” Houtby continued, “we saw it crop up in residential citrus before we saw it in commercial citrus. All of the HLB finds, to date, have been in the Los Angeles Basin.” Houtby said they are working diligently to keep the psyllid population down to decrease the exposure of trees to HLB.

The California citrus industry spends approximately $15 million annually on an ACP assessment program, which includes extensive public outreach. Part of the research entails trapping the pest, conducting survey work in the regions in question, applying treatments in residential areas, and managing a delimitation survey around the area of Los Angeles where the disease has populated.

“That means that we’re scouting very consistently,” explained Houtby, “looking for other trees with the disease and pulling those trees out as soon as we find them. We are doing everything we can here in California to keep the pest and disease from spreading—now that we have it,” she noted.

Alyssa Houtby, director of public affairs, California Citrus Mutual
Alyssa Houtby, director of public affairs, California Citrus Mutual

“The California industry has always been one to use a proactive approach,” Houtby elaborated. “We saw what happened in Florida, and we realized really early on that we couldn’t stand by and wait for this disease to find us. We had to actively go look for it and find it—before it found commercial citrus—and we’ve done that.” Regarding the 22 trees in the state that have been destroyed thus far, Houtby said, “It could be a lot worse if we weren’t as proactive as we are.”

When locating a positive ACP find in a residential area, Houtby noted, generally speaking, homeowners have mostly been compliant. “There are pockets in this state where folks don’t like government coming in, knocking on their door and asking to spray their trees with pesticides. We understand that. It’s an opt-in/opt-out scenario here. We’re not forcing homeowners in most cases to treat their trees.”

Chris Stambach
Chris Stambach, director of industry relations for California Citrus Mutual

“But that’s a different situation if HLB is present,” she emphasized. “Then we do. We get a warrant, and we go in and treat the surrounding trees. If we’re treating in response to an ACP find, homeowners can opt out, but overwhelmingly, they don’t. They support our program. They understand that citrus is a part of the California heritage, they like their citrus trees, and they want to keep them in their yards. They understand that the alternative to not treating is that tree will eventually die if it becomes infected. We’ve worked really hard to communicate to the general public about the seriousness of this issue. We’re pleased with the results.” Houtby said.

Chris Stambach discussed the importance of homeowners having a general understanding of the ACP, so if they find something unusual in their citrus tree, they know to call the local ag commissioner.

Stambach detailed ACP and HLB specifications to increase homeowners’ understanding about their beloved citrus trees. “HLB is symptomatic, but it takes a long time for those symptoms to show up in the tree,” said Stambach. “You really have to know what you’re looking for because some fertilizer deficiency issues in the tree will mimic what HLB looks like.”

“Though the ACP is a really tiny little bug, there are some key signs the public can look for,” explained Stambach. “You want to look for that psyllid and the little tubules it excretes on the new flush of growth—pretty much right there at the end of the terminals where all that new growth comes in the springtime and in the fall. That’s key to California, because there are only certain times of the year when that ACP is actively feeding on the citrus tree.”

California has a real benefit over the Sunshine State, where they have to spray 12 times a year to keep the psyllids at bay. “It hasn’t been effective for [Florida],” noted Stambach. “We had a couple of growers out this last winter to our Citrus Showcase. They planted new trees, 4 years old, and although they spray 12 times a year, their orchards are 100% infected with HLB. That’s the devastation that this insidious disease can bring. It’s really difficult to get your hands around it because it takes so long to be able to detect it.”

Another benefit for California citrus, according to Houtby, is, “We have a lot of areas in the state where we don’t have to spray at all because we can use beneficial insects. That’s just the great part about farming in California.”

Asian Citrus Psyllic Yellow Trap 2 (Source: Citrus Pest & Disease Prevention Program)
Asian Citrus Psyllic Yellow Trap (Source: Citrus Pest & Disease Prevention Program)

Houtby and her team often look to Florida for ideas and recommendations on what has worked for them, what hasn’t and what citrus growers here can do to prevent the disease from taking hold of their citrus. She clarified that 90 percent of the Florida citrus market is used for juice production; whereas, California is a “fresh-oriented industry, meaning that over 90 percent of our product goes into the fresh market.”

Although California citrus looks for recommendations from Florida, “here in California, there are a lot of things that we can’t afford to do because of the [fresh] market that we’re serving,” said Houtby.”  That is what we’re fighting so hard to maintain because we cannot sustain as long as Florida has; we don’t have the luxury of sending a bad-looking piece of fruit into the marketplace like Florida can, because they just juice it. Knowing that, we’re working really hard to never get to the point that Florida has reached.”

As if the dire situation in Florida couldn’t be any worse, they battled with “another deadly bacterial-based citrus disease, citrus canker, brought in from the far reaches of the world,” Stambach said. “That’s a concern we always have with importing citrus. When we import Argentine lemons, for example, we risk our domestic plant health by exposing orchards to a lot of plant diseases they have that we don’t. We want to keep those out of our country,” noted Stambach.

Abandoned citrus trees also pose problems for the industry; they can be sanctuaries for ACP. “If those trees are dead, that’s not a problem. They may look bad, but if they are not living, that’s not a problem. It’s when those trees aren’t cared for, aren’t sprayed in a normal routine, and there is a flush of new growth, the trees provide a sanctuary for the psyllids,” he said.

Abandoned Citrus
Abandoned Citrus

“And ACP are very good at finding citrus. They’ll target the perimeters of new growth on the very first citrus they find. Boom, they’re right on it,” he noted.

“Those abandoned groves create a real problem, particularly when they’re in close proximity to other commercial acreage or even homeowners,” he said. Neglected neighborhood citrus trees can become ACP sanctuaries. “ACPs will feed on them and move on to another tree, and feed there,” Stambach explained. “All that time, if an ACP is infected with the HLB bacteria, it will spread that disease, with a latency period of 2 to 5 years.”

Stambach and his team are working on a critical program in Southern California to remove abandoned citrus trees. “Sometimes it’s just getting a hold of the landowner and making them aware of the situation,” he said. “Our county ag commissioners are really key in contacting those people. We’ve had growers go in and spray their neighbor’s orchard to help them out. There are a lot of different ways to attack that problem.”

Compared to counties in the San Joaquin Valley, Riverside and Ventura Counties typically have a big-ag urban interface, which means there is a lot of acreage intermixed with home sites—small homes with citrus trees. Stambach said, “It’s not really commercial production, but it’s a significant amount of acreage with a number of trees that don’t get treated.”

“We’ve gotten some support from some of our partners in the chemical industry. Bayer CropScience has stepped up and worked with us to put together a program. We’re really happy. We’re working hard to take [ACP and HLB] out.” Stambach said.

“Fresno has even found ACPs in residential areas,” commented Houtby on the Central Valley situation. “ACPs are endemic in Southern California, but we’re still at a point in the Central Valley at which we can control these populations and knock them down really quickly when they arrive here.”CA Citrus Mutual

Houtby points to the Central Valley’s vulnerability when citrus plant material is moved over the grapevine or from the Central Coast. “We ask that homeowners, and the citrus industry as well, not move plant material out of Southern California into the Central Valley,” she stated. “The psyllid lives on that plant material and not on the fruit. If you’re going to buy a citrus tree, buy it at a local plant nursery or a local Home Depot or Lowe’s. Don’t buy it in Southern California and drive it to the Central San Joaquin Valley,” she urged.

“Our biggest task for homeowners is that they cooperate when the California Department of Food and Agriculture knocks on the door and wants to look at their trees,” Stambach said. “That is the best way you can help us win this battle against the ACP.”

Homeowners can learn how to protect their citrus trees at:

CaliforniaCitrusThreat.org

U.S. Department of Agriculture

California Department of Food and Agriculture

University of California Cooperative Extension

Contributors to this report include Patrick Cavanaugh and Emily McKay Johnson.

Dogs Detect Citrus Diseases

Dogs Detect Citrus Diseases

By Charmayne Hefley, Associate Editor

Animals have been known to be able to use their senses to detect things that humans require extensive technology to detect. Mary Palm, USDA Animal and Plant Health Inspection Service (APHIS) national coordinator for citrus pest programs, said dogs have been successfully trained to detect canker disease, and now Huanglongbing disease (HLB), in citrus.

“Over the past four to five years,” Palm said, “a researcher in Florida first determined dogs could actually detect canker, began training dogs,” Palm said, “and then trained different sets of dogs to detect it. It turned out that they were very good at it. In a demonstration there, none of the people could find any symptoms in a particular citrus tree, but the dogs came through and found the symptoms. Once the people came back and looked very closely, sure enough, it was there.”

Palm said the USDA Huanglongbing Multi Agency Coordination (MAC) Group funded research to determine if dogs could detect HLB in citrus as well as they detected canker. There are now five dogs being trained and tested daily. If grower demand increases, the use of canines in pest management could increase.

Palm said they will probably come up in the next year or two with certification criteria for other companies to train dogs and certify them as detectors. Palm said, “They would be able to get a certificate to show they had conducted all of the tests necessary with the [proper] degree of accuracy.” Palm said the dogs in this program have a 99 percent success rate at detecting HLB disease.

Palm said approximately 80 trees are put inside every night, the positive ones in one greenhouse and the negative ones in another. The trees are taken out the next day and positioned in different patterns for dogs to inspect throughout the day. When the dogs are brought out, even their trainers don’t know which trees are positive or negative. The trained dogs are more than 99 percent accurate.”

Link:

USDA Huanglongbing Multi Agency Coordination (MAC) Group Funded Projects: List for the Control and Mitigation of Huanglongbing FY 2015

USDA Funds $30M to Fight Citrus Greening

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.

USDA NIFA Citrus Greening Awardees Fact Sheet
USDA NIFA Citrus Greening Awardees Fact Sheet