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.

Citrus Showcase Had Strong Showing

Citrus Showcase News

Area-Wide ACP Spraying To Start Soon

By Patrick Cavanaugh, Editor

The 2014 California Citrus Showcase in Visalia, hosted by the Exeter based California Citrus Mutual, brought a record crowd.

“It was the largest event we have had in our 15 years,” said Joel Nelson, President of the California Citrus Mutual, the organization that hosts the annual event. “We had about 100 exhibitors and about 650 people for lunch, and roughly 1,000 growers who meandered though the entire show throughout the course of the day,”  Nelson said.

There were also six workshops that focused on the Asian Citrus Psyllid, the vector of the fatal HLB disease, water quality and even GMO research to help find HLB resistant citrus stock.

“What we wanted to do  was  give our growers a bit of optimism,” said Nelson. “Our citrus industry has been hit with so many challenges, not withstanding the ACP/HLB issue, the  disease that is ravaging Florida; the freeze in December and now the drought conditions.”

“We wanted the industry to be aware that there are opportunities to fix these problems that are facing our industry, and I think that the growers left here much more positive than when they came in,” said Nelson.

Joel Nelson and Felicia Marcus
Joel Nelson, President of California Citrus Mutual, with Felicia Marcus, Chair of the State Water Resources Control Board

Some of the highlights of the half-day event included:

The keynote speaker for the inaugural Citrus Showcase Breakfast was Felicia Marcus, Chair of the State Water Resources Control Board. “This is a scary and uncertain drought, and it is going to be painful,” Marcus said.

“There is no question that we would not be where we are today if we had more storage,” Marcus said. “We are concerned with climate change when we could be facing the regular loss of half of our storage…snow in the mountains.”

She also said that nitrates in the ground water are a legacy issue.

Another big topic centered on what can be done to suppress the ACP, which will help prevent HLB infected trees.

The San Joaquin Valley Citrus Industry has been discussing area-wide treatment of orchards, on top of the mandated treatments when a psyllid is found.

Kevin Severens
Kevin Severns

“As it stands right now, there would be logical areas where geographically it would make sense to have that as a treatment zone,” said Kevin Severns, a grower and  the new Chairman of California Citrus Mutual.

“There will be area captains in each of the zones, such as a grower or other person well-known in the area. They would work with an area-wide coordinator, and the state-wide coordinator will be responsible for coordinating treatment,” Severns said.

The spray timing would be when new growth flushes occur on citrus trees, a time when the ACP is attracted too.

Attendees also heard from Mike Sparks, President of the Florida Citrus Mutual, who painted a grim picture of what has happened to the Florida citrus industry and described its uncertain future.

“The losses due to HLB over the last seven years have been more than $70 million, said Sparks. “Before HLB disease hit us, the Florida Citrus industry was at 815,000 acres. Today the acreage is at 525,000.  And we are losing orange juice processing plant infrastructure due to the low volume, pegged at only  115 million boxes, down from 133 million boxes last season.”

“Every orchard in the state is infected and growers are doing every thing they can to reduce ACP numbers and remove HLB-infected trees,” said Sparks.

Mike Sparks President Florida Citrus Mutual
Mike Sparks

There is particular concern for orchards that have been abandoned.

“The cost of production in order to fight ACP with sprays continues to go up, while production goes down. We know this is not sustainable,” said Sparks.

“Over the years, Florida citrus growers have had to deal with freezes, citrus canker, and even powerful hurricanes that have wiped out orchards. At least those orchards could be replanted and production would resume. HLB, is a far different threat. It has put growers to their knees,” Sparks said.