California Ag Network

Tag: Asian Citrus Psyllid

  • CLas-positive Asian Citrus Psyllid Found in Riverside Commercial Grove

    An Asian citrus psyllid (ACP) sample – confirmed positive for Candidatus Liberibacter asiaticus (CLas) the bacteria that causes Huanglongbing (HLB) – was collected from a commercial citrus grove in the Woodcrest area of Riverside County. Confirmed by Citrus Research Board’s Jerry Dimitman Laboratory, this single adult psyllid is the first CLas-positive ACP found in a commercial citrus grove in California.

    While a positive ACP detection in a commercial grove is cause for serious concern, as of today, HLB has not been detected in any California commercial groves. That said, it is more crucial than ever that we stop the disease from spreading by eradicating the Asian citrus psyllid in commercial groves. 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.

    An expansion of the HLB quarantine zone will not be established as a result of the CLas-positive ACP detection and CDFA staff is swiftly conducting surveys and collecting samples per the ACP/HLB Action Plan  from the perimeter of all commercial groves and all residential HLB host plants that are located within a 250-meter radius around the find.

    While treatment is not mandatory as a result of the detection, all growers within 250-meters of the find site will be notified to apply insecticides to all HLB host material within the designated area with materials recommended by the University of California (UC).

    Currently, the best way to stop the disease from spreading is to stop the ACP. To stop the ACP, we must restrict its movement and suppress existing psyllid populations. It is critical to follow best practices and review recommendations from the UC on how to protect commercial citrus groves from HLB. Regulations are in place to help prevent the spread of the pest and disease. All growers, packers and haulers must comply with all California Department of Food and Agriculture, county and federal regulations, including quarantines.

    Growers in Riverside County may contact the County Agricultural Commissioner’s office or the CDFA Pest Hotline at 800-491-1899 for additional information. If you see or suspect ACP or HLB symptoms in your grove, please notify the CDFA hotline. – By the Citrus Pest & Disease Prevention Program

  • Argentine Ant Inhibits Biocontrol Options for Deadly Citrus Pests

    Growers want to minimize their pesticide use in the orchard; but when you have invasive pests like the Argentine Ant protecting aphids and psyllids from natural predators, your options are limited.  Watch this brief interview with Greg Simmons from the USDA-APHIS as he explains and read more about it in California Fresh Fruit Magazine.

  • CA Red Scale Resurfaces in Citrus Due to Asian Citrus Psyllid Treatments

    Bennett Water Systems

    With the threat of the deadly Huanglongbing citrus greening disease coming to the state, California citrus growers are doing all they can to keep the disease vector asian citrus psyllid out of their orchards; however, these treatments are also taking out natural enemies for red scale, causing a resurgence of the pest in California orchards. Watch this brief video as researcher David Holden explains, and read more about it in California Fresh Fruit Magazine.

  • Challenges and Successes for the California Citrus Industry

    With all the regulatory and economic challenges facing our agricultural industries, California growers understandably have a lot to grunt and complain about; however, if growers see these challenges as opportunities and work together to overcome them, so much more can be accomplished, as has been done in the California citrus industry.  Check out this brief video interview with former President of the California Citrus Mutual, Joel Nelsen, as he explains. Read more about it in the coming issue of California Fresh Fruit Magazine.  Don’t currently receive the publication?  Subscribe for free at https://malcolmmedia.com/california-fresh-fruit-subscriptions/.

  • CA Detections of Citrus Disease HLB up 160 Percent

    HLB infected Tree

    Stakes at All-Time High for Backyard & Commercial Trees in 2019

    Detections of Huanglongbing (HLB), an incurable plant disease that kills citrus trees, increased by 160 percent in 2018 compared to the previous year, signaling the growing threat to the state’s iconic citrus trees, landscape and economy.

    HLB is spread by a small pest called the Asian citrus psyllid as it feeds on citrus tree leaves. The disease is not dangerous to humans or pets, but it is fatal for citrus trees and has no cure. Once a tree is confirmed with the disease, it must be removed from the property in order to protect neighboring citrus trees.

    The disease was first discovered in California in 2012 in Hacienda Heights. HLB was detected in 269 trees in 2017 and 699 trees in 2018, with a majority of these occurring in Los Angeles and Orange counties. The disease has not yet been detected in a California commercial grove.

    HLB has devastated commercial citrus production in Florida. Over the course of 10 years, Florida’s commercial citrus industry lost $7.8 billion in revenue, 162,200 citrus acres and more than 7,500 jobs due to HLB. Should the disease spread from backyard trees in Southern California to nearby commercial citrus groves, the livelihood of California’s citrus production could impact about 3,900 farmers and 292,000 acres of citrus production in the state. Commercially grown citrus contributes $7 billion in economic impact to the state and employs more than 22,000 individuals.

    “The livelihood of California’s commercial citrus industry and the generations of families it supports is at risk because of HLB,” said Jim Gorden, a citrus grower in the San Joaquin Valley and chair of the Citrus Pest & Disease Prevention Committee. “We are at a crossroads, and we must all work together to do what is necessary to protect our citrus.”

    Asian Citrus Psyllid Adults

    The California Department of Food and Agriculture (CDFA) has established quarantines throughout the state that limit the transport of citrus across state and international lines, and between areas where the psyllid and disease have been found. Additionally, CDFA has agriculture crews canvasing the state to inspect backyard citrus trees for the Asian citrus psyllid and HLB.

    “The Department is committed to our partnership with California’s commercial citrus industry and residential citrus growers to fight HLB,” said Victoria Hornbaker, interim director of the citrus program at CDFA. “With more than half of California residences estimated to have a citrus tree on their property, and California citrus production supporting billions of dollars in our state’s economy, we all play an instrumental role in protecting our citrus.”

    California residents play an important role in protecting the state’s citrus trees. Residents should: 

    • Proactively inspect their citrus trees for the Asian citrus psyllid and HLB monthly, and whenever watering, spraying, pruning or tending trees.
      • Adult Asian citrus psyllids are brown, about one-eighth of an inch long, and feed with their body at a 45-degree angle on citrus leaves.
      • Symptoms of HLB include blotchy and yellowing leaves, premature and excessive fruit drop, lopsided fruit, and bitter, inedible fruit.
    • Call the state’s pest hotline at 800-491-1899 if the pest or disease is spotted.
    • Cooperate with agriculture officials who may ask to inspect or treat their citrus tree.
    • As part of tree maintenance, visit a local nursery or garden center to get advice on products that can help protect citrus trees.
    • When pruning citrus trees, be sure to dry out citrus clippings or double bag them before removing the plant material from the property.
    • Refrain from moving citrus plants, foliage or fruit as doing this may unknowingly spread the pest.

    More information and photos of Asian citrus psyllids and HLB symptoms are available at CaliforniaCitrusThreat.org.

  • Huanglongbing Eradication Status in California Citrus

    To date, the deadly citrus greening disease Huanglongbing or HLB has not been found in California’s commercial citrus orchards; however, it’s only a matter of time. HLB strikes continue to be detected in residential areas, and its vector has spread all over the state. Watch this brief interview with Victoria Hornbaker, head of the CDFA’s statewide citrus program, as she shares the current status of the spread of HLB and its vector the Asian citrus psyllid, and CDFA’s eradication efforts. Read more about it in California Fresh Fruit Magazine. Don’t currently receive California Fresh Fruit Magazine? Subscribe for free at https://malcolmmedia.com/california-fresh-fruit-subscriptions/.

  • Citrus Crop Update with Central Valley Grower Arlen Miller

    Harvest of the 2018-2019 citrus crop is underway, and growers are excited to reap the fruits of their labors.  Watch this brief interview with third generation  Central Valley citrus grower Arlen Miller as he shares his perspective on the coming crop and read more about him and his many diverse varieties of citrus in the coming issue of California Fresh Fruit Magazine.  Don’t receive California Fresh Fruit Magazine?  Subscribe for free at https://malcolmmedia.com/california-fresh-fruit-subscriptions/.

  • NEW STUDY REVEALS CA CITRUS ECONOMIC IMPACT 

    Citrus Research Board Quantifies Industry Importance

        The total economic impact of California’s iconic citrus industry is $7.117 billion according to a new study commissioned by the Citrus Research Board (CRB).

    Bruce Babcock, UC Riverside

    “In updating our economic analysis, we selected a well-known expert, Bruce Babcock, Ph.D., a professor in the School of Public Policy at the University of California, Riverside, to conduct the research. His findings quantified the significant impact of citrus on California’s economic well-being,” said CRB President Gary Schulz.

    According to Babcock, the California citrus industry added $1.695 billion to the state’s Gross Domestic Product (GDP) in 2016. “California citrus is a major contributor to the economic value of the state’s agricultural sector and is much larger than just the value of its sales,” he said. “Estimated full-time equivalent California citrus jobs totaled 21,674 in 2016-17, and estimated wages paid by the industry during that same timeframe totaled $452 million.”

    Babcock added, “The application of management skills and capital equipment to efficiently utilize land and water to produce high-quality citrus also generates upstream and downstream jobs and income that magnify the importance of citrus production beyond its farm value.”

       In 2016-17, the most recent marketing year of data compilation, Babcock found that the total direct value of California citrus production was $3.389 billion. This value generated an additional $1.263 billion in economic activity from related businesses that supplied materials and services to the citrus industry. Layered on top was another $2.464 billion in economic activity generated by household spending income that they received from California’s industry, according to Babcock, thus rendering a total economic impact of $7.117 billion.

    The study revealed that 79 percent of California’s citrus was packed for the fresh market and 21 percent was processed in 2016-17, which is economically significant because fresh market fruit has a higher value than processed fruit.”

    Of further note, California produced about 95 percent of all U.S. mandarins in the most recent reporting season.

    Joel Nelsen, President of the California Citrus Mutual

    California Citrus Mutual President Joel Nelsen commented, “The “wow” factor in this report is something as it relates to gross revenues and positive impact for the state, people and local communities.  This enthusiasm must be tempered by the fact that huanglongbing (HLB) can destroy all this in a matter of a year if the partnerships that exist between the industry and government cannot thwart the spread of this insidious disease.  Just this week, coincidentally, Brazil authorities reported a 20% reduction in fruit volume.  Reading how that would affect our family farmers, employees and the state is sobering.”

    The CRB study also looked at the possible impact of a potential 20 percent reduction in California citrus acreage or yield or a combination of the two that could result from increased costs associated with meeting government regulations, combatting the Asian citrus psyllid (ACP) and warding off the invasion of HLB, a devastating disease that has decimated citrus production in many other growing regions such as Florida. Babcock calculated that such a reduction could cause a loss of 7,350 jobs and $127 million in associated employment income and could reduce California’s GDP by $501 million in direct, indirect and induced impacts. The CRB currently is devoting most of its resources to battling ACP and HLB to help ensure the sustainability of California citrus.

    Babcock is a Fellow of the Agricultural and Applied Economics Association and has won numerous awards for his applied policy research. The economist received his Ph.D. in Agricultural and Resource Economics from the University of California, Berkeley and his Masters and Bachelors degrees from the University of California, Davis.

    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. Read the full report on the “Economic Impact of California’s Citrus Industry” Here.

  • Research Reveals a New Direction for Halting the Citrus Greening Epidemic

    Ithaca, New York, (April 2, 2018) – New clues to how the bacteria associated with citrus greening infect the only insect that carries them could lead to a way to block the microbes’ spread from tree to tree, according to a study in Infection and Immunity by Agricultural Research Service (ARS) and Boyce Thompson Institute (BTI) scientists.

    Citrus greening, also known as “huanglongbing,” is a serious disease dramatically affecting citrus production across the world. Trees with this disease all die after only a few years. Citrus greening has been detected in every citrus-producing county in Florida, throughout the southern citrus growing states and in isolated spots in southern California. There is no effective prevention or cure.

    The disease is associated with the bacterium Candidatus Liberibacter asiaticus, CLas for short, which is spread from tree to tree only by a tiny insect vector—the Asian citrus psyllid. If CLas cannot infect the psyllid, its ability to spread citrus greening is halted.

    With the long-term goal of disrupting this CLas-Asian citrus psyllid interaction, research molecular biologist and BTI professor Michelle Heck, with the ARS Emerging Pests and Pathogens Research Laboratory, and BTI researcher Marina Mann focused on an important point: not all psyllids spread CLas equally well.

    To be spread by the Asian citrus psyllid (ACP) effectively, the bacteria must pass through the cells lining the insect’s gut and multiply. Scientists in Heck’s lab had previously shown that the gut cells of adult ACP show severe stress responses when infected by CLas. The cell nuclei become fragmented, and some cells react to the point of dying, allowing the bacteria to move out of the psyllid and into the tree.

    Now, the researchers have found that, unlike adult psyllids, young psyllid nymphs appear to be resistant to the effects of exposure to CLas, and their nuclei rarely reach the same level of disruption. This means CLas cannot enter psyllid gut cells to multiply.

    The next step will be to identify the mechanism for this resistance in the nymphs so that it might be manipulated to also halt the spread of CLas by the adults. An important clue lies in how psyllid nymphs interact with symbiotic bacteria in their gut, especially Wolbachia pipientis.

    Many insects are hosts for Wolbachia and often depend on these bacteria for important benefits—much like how human health depends on gut bacteria. In their study, Mann and Heck showed that in psyllid nymphs, Wolbachia and CLas are commonly found within the same cells.

    The authors hypothesize that, in accommodating the beneficial bacteria, the nymphs also let in more CLas. This is supported by their finding that CLas levels in psyllid nymphs are strongly correlated with Wolbachia levels. Though this link remains to be tested directly, understanding its mechanism could yield an important target for disrupting CLas-psyllid interaction.

    “CLas exploits the way nymph and adult psyllids differ in their guts to gain entry into its insect vector,” Heck said. “We may be able to use this new foothold in our understanding to develop ways to block transmission by insects in the citrus grove.”

    If this works, “citrus growers will be in a much better situation in terms of disease control and saving the U.S. citrus industry,” said Dan Dreyer, Chairman of the California Citrus Research Board, which funds this and other research aimed at developing a management strategy for citrus greening.

    “There are still many unanswered questions about CLas, how it is acquired and transmitted via the Asian citrus psyllid, and how it causes the disease,” continued Dreyer. “The more we learn about CLas and its vector, the closer we will get to moving citrus production past the threat of citrus greening.”

    The Agricultural Research Service is the U.S. Department of Agriculture’s chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. Each dollar invested in agricultural research results in $20 of economic impact.

  • Statewide Citrus Grower Approaches for Controlling ACP & HLB

    Special Thanks to This Video’s Sponsor!

    The deadly HLB spreading asian citrus psyllid (ACP) continues to make its way through citrus orchards all over California, and the industry is going to need to work together to slow the spread of this pest to buy researchers sufficient time to come up with a solution for HLB. Watch this brief interview with UC Entomologist Beth Grafton-Cardwell as she discusses what works for controlling ACP and growers are doing in southern and central California to manage the pest.