For the past 18 months, a team led by University of California research entomologist Beth Grafton-Cardwell has been conducting an Asian citrus psyllid monitoring project to determine the efficacy of Ventura County's area-wide ACP suppression strategy. Based on her analysis of the survey data, Dr. Grafton-Cardwell has recommended changes in the area-wide management (AWM) protocol to provide better control of the invasive pest. The Ventura County ACP-HLB Task Force has endorsed her recommendations and incorporated them into the AWM schedule for 2018-2019.
The primary change will be the addition of a second fall treatment, which may be a perimeter spray, for lemons and mandarins. Fall is when ACP populations reach their highest level, and the research data indicate a single pesticide application is inadequate. The research data also show that ACP is most abundant on grove perimeters, and only expands into the center rows when the population is large. In recognition of this, the new Task Force protocol allows one of the two fall applications to be applied to only the grove perimeter, as long as the grower, grove manager or PCA/PCO has scouted the orchard and determined that center rows are free of ACP nymphs on flush. The other fall application, however, must cover the entire grove.
As in previous cycles, the treatment window for each psyllid management area (PMA) will last three weeks, but it now will overlap with the next window by two weeks instead of one. This will compress each treatment cycle from four months in length to two and a half months, heightening the area-wide effect. (See below for the schedule.)
The annual AWM program for lemons and mandarins will now consist of four applications: a coordinated AWM whole-orchard treatment in winter, individual applications of an ACP-effective material (either alone or piggybacked on a spray for another pest) in late spring-early summer, and two coordinated AWM treatments in late summer and fall (one of which may be a perimeter spray).
The annual cycle for oranges, which do not flush year-round, remains two coordinated applications, one during the first fall window and one in the winter. For organic growers, each "treatment" must consist of two applications of Entrust and oil or Pyganic and oil, or other approved alternative material, to compensate for their limited residual activity. The list of approved materials for both conventional and organic operations is at http://ipm.ucanr.edu/PMG/r107304411.html.
Members of the Ventura County citrus community are invited to a workshop to learn more about these changes, and the research data upon which they are based. The workshop will be from 9:30 to 11:30 a.m. on Thursday, April 26, at the Agriculture Museum, 929 Railroad Ave., Santa Paula. Attendance is free, but advance registration is required. Please register online at: https://vctaskforce-workshop.eventbrite.com.
During the workshop, Dr. Grafton-Cardwell will present findings from her continuing survey of ACP populations across the county, including data on the effects of AWM pesticide treatments on ACP abundance. Other speakers will present updates on the statewide Citrus Pest and Disease Prevention Program, the status of Huanglongbing disease in California, and grower participation in the local ACP suppression effort.
The Task Force is also planning outdoor workshops to help grove owners, managers or farm employees develop an effective ACP scouting strategy. Topics will include how to scout for ACP, and how to identify symptoms of HLB. More information will be distributed in coming weeks.
The following is the new schedule for Fall 2018 and Winter 2019 treatments, organized by groups of PMAs. Overview maps of Ventura County's PMA boundaries are available at http://www.farmbureauvc.com/issues/pest-issues/asian-citrus-psyllid#task-force.
Individual maps of Ventura County's PMA boundaries, along with many other documents pertaining to the Ventura County AWM program, can be viewed or downloaded at
As was the case with the previous AWM treatment cycles, growers will be notified about the date of their treatment window either by their packinghouse field reps, their PCAs or by the Ventura County grower liaisons: Sandra Zwaal (firstname.lastname@example.org) and Cressida Silvers (email@example.com). It will be up to growers to work with their PCAs and applicators to schedule those treatments.
This note from Cressida Silvers, either go to Temecula or maybe do a more local version of the training:
The upcoming CAPCA meeting (see below for details) in Temecula is a 2-day event (12 CEUs), including a workshop and field visit focused on detecting live ACP in citrus trees, and using monitoring strategies to evaluate ACP presence in orchards.
If there is enough interest locally (SLO, Santa Barbara, Ventura), we could put on a similar workshop/field training for ACP monitoring for anyone interested. Let me know if that would be helpful, and how far you would be willing to travel for that.
ACP/HLB Grower Liaison
Ventura, Santa Barbara and San Luis Obispo Counties
CAPCA Spring Summit Focuses on
Asian Citrus Psyllid:
April 24 – 25
The California Association of Pest Control Advisers (CAPCA) will host its 2018 Spring Summit on April 24 – 25 in Temecula. Summit attendees will tour UC Riverside's citrus grove and experiment station, and will learn about Asian citrus psyllid mitigation standards for bulk citrus movement, scouting techniques, identification and management strategies.
With more than 500 HLB-positive trees confirmed in Southern California, it is critical that pest control advisers involved with citrus stay up to date with ACP detection and management strategies. The Spring Summit will include the following topics and speakers:
- Strategies for management of Asian citrus psyllid in California – Dr. Beth Grafton-Cardwell, University of California Division of Agriculture and Natural Resources
- Mitigation standards for the new Asian citrus psyllid regional quarantine – Victoria Hornbaker, California Department of Food and Agriculture
- Scouting techniques and identification of Asian citrus psyllid in the field – Alan Washburn, Citrus Pest & Disease Prevention Program
- Update on Asian citrus psyllid and HLB management – Bob Atkins, Citrus Pest & Disease Prevention Program
The event is accredited for 12 hours (2.50 Laws and 9.50 Other) of continuing education units by the Department of Pesticide Regulation, as well as 11.50 California Crop Advisers hours. To view the full program schedule, click here.
To register for the CAPCA Spring Summit, click here.
This is the summary of a recent article by Allen Morris, a retired University of Florida Extension Economist
Even when a cure for HLB is implemented, unless something is done to stop the decline in orange juice consumption, the citrus-growing part of the industry will become too small to support the infrastructure of input suppliers, harvesters, grove caretakers, etc. necessary for it to function competitively. For example, assume that the lower prices from lower cost production get into the orange juice market evenly over the 2023–24 to 2031–32 nine-year period, reflecting the time required for fruit produced from new plantings of HLB-resistant trees to increasingly impact prices. Ten years after the first plantings, by 2031–32, only 58 million boxes of Florida oranges and no orange juice imports will be needed. In spite of an 11 percent increase in the orange juice market stimulated by the lower prices, the underlying rate of decline in orange juice consumption eliminated its benefit.
The three major orange juice brands will probably continue mainly as juice storing, blending and packaging operations, using orange juice imported primarily from Brazil and Mexico, but also using juice from the small declining volumes of Florida fruit still available to process. However, because of the high costs of processing small volumes of fruit in the large processing plants owned by the brands and the companies processing oranges for the Coca-Cola Company's Minute Maid and Simply brands, it is likely that one of the bulk processors may have an opportunity to process fruit for all three of the brands. This would reduce costs by processing all of the industry's remaining volumes of oranges in one plant, and thus allow that processor to continue to operate. The bulk processors, other than the ones storing and blending juice for the Coca-Cola Company's Minute Maid and Simply brands and the one which processes the remaining volumes of oranges, will soon have no economic reason to exist in Florida. Private labels' orange juice needs will be supplied by imports, primarily from Brazil and Mexico.
Because of the declining U.S. orange juice market, the brands will probably increase their focus on the European orange juice market, which, as was pointed out, is being positioned to grow. There will also probably be a proliferation of exotic juice blends like blueberry mango, pomegranate limeade, strawberry banana, watermelon, berry greens, etc. being introduced by the brands as they begin to position themselves away from citrus.
This conclusion doesn't have to happen. But it is likely to happen if something isn't done to restore the U.S. orange juice market to growth. One way to fund that is to partner with Citrus BR the way AIJN and the European orange buyers/packagers are doing. The U.S. orange juice market is second only to Europe in importance to Brazil as an export market for its orange juice. If approached, the Brazilians would probably be interested in working with the Florida Citrus Commission the way they are working with AIJN to restore growth to the U.S. orange juice market.
For the complete article, go to:
ITHACA, N.Y. — 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.
The number of trees confirmed as being infected by HLB has reached 520 (300 in Orange County, 217 in Los Angeles County and 3 in Riverside County). All were in residential settings, not commercial groves. The HLB quarantine boundaries and the latest tally of HLB confirmations, updated weekly, is available online at https://citrusinsider.org/maps/. As confirmations increase and spread closer to commercial citrus, it is a good time to consider removing citrus trees not worth the resources required to protect them from ACP and HLB.
ACP Areawide Treatments
The winter ACP areawide treatment window ended March 16. Please remember to submit your Pesticide Use Reports (PURs) to the County Ag Commissioner's office immediately after treatment to ensure your ACP treatment is recognized. ACP treatment percentages will be calculated in about a month, to allow time for all PURs to be filed.
The spring-summer uncoordinated ACP treatment window begins now and continues through July. Although these treatments are not coordinated, psyllid populations need to be kept low to reduce the risk of HLB. Scout/monitor and treat if you see any ACP, and use an ACP-effective material during spring/summer management. Click here to access the University of California recommendations for ACP monitoring.
Save the Date
The fall 2018 areawide-treatment protocols and schedule will be discussed at a grower workshop on Thursday, April 26, at the Agriculture Museum in Santa Paula. Additional details will be distributed soon.
The Citrus Pest & Disease Prevention Program will conduct a free crew boss training from 7 to 9 a.m. on March 28 at the Limoneira Visitor Center, 1141 Cummings Road, Santa Paula. Growers and packers are encouraged to send crew bosses, foremen, ranch managers and packinghouse representatives to this hands-on learning experience. Presented in Spanish, these trainings will inform front-line leaders in the field about what they can do to reduce the risk of spreading HLB and ACP at work. Click here for more information and to register.
The Citrus Pest and Disease Prevention Committee will meet in Ventura County on Wednesday, May 9. Attendance is free. The CDFA site with agenda, venue, and webinar information is at https://www.cdfa.ca.gov/citruscommittee/. On a related note, the CPDPC recently approved the appointment of Ted Grether of Somis to represent coastal citrus growers on the committee. Ted works for the family farming business, Grether Farming Company, growing lemons, avocados and mandarins as an operations manager and administrator.
Please direct questions about regulatory or compliance agreement issues to the County Agricultural Commissioner's Office (David Navarro, firstname.lastname@example.org, 805-388-4343) or CDFA (Michael Soltero, Michael.Soltero@cdfa.ca.gov, 805-445-1382).
Click here to sign up for the Ventura County ACP-HLB Task Force mailing list.
If you need pest control or tree removal referrals, please contact your grower liaisons, Sandra Zwaal and Cressida Silvers. Low- or no-cost tree removal assistance can also be obtained through California Citrus Mutual's ACT NOW program. More information can be found at https://citrusmatters.cropscience.bayer.us/commercial-grower/act-program.