- Author: Ben Faber
SACRAMENTO — The California Department of Food and Agriculture (CDFA) and the United States Department of Agriculture (USDA) have established a 94-square mile quarantine in portions of Riverside and San Bernardino counties following the detection of the citrus disease huanglongbing (HLB), or citrus greening, in a single citrus tree in the city of Riverside. HLB is a deadly disease of citrus plants and closely related species, and can be transmitted from tree to tree by the Asian citrus psyllid.
The quarantine boundaries are on the north, Interstate 10; on the east, Box Springs Mountain Reserve; on the west, Riverside Municipal Airport; and on the south, East Alessandro Boulevard. HLB quarantine maps for Riverside and San Bernardino counties are available online at: www.cdfa.ca.gov/plant/pe/InteriorExclusion/hlb_quarantine.html. Please check this link for future quarantine expansions in these counties, should they occur. Quarantines are already in place for HLB in portions of Los Angeles and Orange counties.
The quarantine will prohibit the movement of all citrus nursery stock out of the area, while maintaining existing provisions allowing the movement of only commercially cleaned and packed citrus fruit. Any fruit that is not commercially cleaned and packed, including residential citrus, must not be removed from the property on which it is grown, although it may be processed and/or consumed on the premises.
Residents are urged to take several steps to help protect citrus trees:
- Do not move citrus plants, leaves or foliage into or out of the quarantine area, or across state or international borders. Keep it local.
- Cooperate with agricultural crews placing traps, inspecting trees and treating for the pest.
- If you no longer wish to care for your citrus tree, consider removing it so it does not become a host to the pest and disease.
CDFA crews have already removed the infected tree and are in the midst of a treatment program for citrus trees to knock down Asian citrus psyllid infestations within 800 meters of the find site. By taking these steps, a critical reservoir of the disease and its vectors will be removed, which is essential to protect the surrounding citrus from this deadly disease.
HLB is a bacterial disease that attacks the vascular system of plants. It does not pose a threat to humans or animals. The Asian citrus psyllid can spread the bacteria as the pest feeds on citrus trees and other plants. Once a tree is infected, there is no cure; it typically declines and dies within a few years.
CDFA, in partnership with the USDA, local county agricultural commissioners and the citrus industry, continues to pursue a strategy of controlling the spread of the Asian citrus psyllids while researchers work to find a cure for the disease.
—California Department of Food and Agriculture
Over 20 new trees in Southern California have been confirmed HLB-positive. The new finds raise the total number of trees with huanglongbing disease found in California to around 100. All of the trees found in the state have been located in residential areas.
The Citrus Pest and Disease Prevention Program (CPDPP) issued a press release that stated 21 trees in Anaheim, and four trees in Pico Rivera tested HLB-positive. The CPDPP, a program of the California Department of Food and Agriculture (CDFA), stated the current quarantine in Southern California would be slightly expanded in Orange and Los Angeles Counties.
The new detections were found due to intensive surveying that's part of the response program. Highly trained crews sample trees where HLB-positive Asian citrus psyllids have been found. CDFA says their Sacramento facility can process 10,000 samples a month.
All of the detections in California have been residential trees. The CPDPP is currently running an outreach program that involves public service announcements, coordination with officials, and large public events in the quarantine area. The goal is to educate residents on the disease and the insect that spreads it. Go to the CPDPP website to find out more about the disease, insect, and quarantines.
Photo: HLB symptoms
- Author: Ben Faber
Task Force ACP-HLB update
HLB update
To date, 232 residential citrus trees in Southern California have tested positive for the HLB bacterium. All have been, or are being, removed. Most were in neighborhoods in LA and Orange counties. Three of the trees were in Riverside, and although they were residential trees, the resulting 5-mile radius quarantine for HLB is affecting a few growers in Riverside and San Bernardino counties.
The latest HLB quarantine map with the running tally of HLB detections in the state can be found at the Citrus Insider website: https://citrusinsider.org/maps/. The maps are updated every week.
Tree removal
As HLB detections increase and spread closer to commercial citrus, it is a good time to consider removing any citrus trees that are unloved, uncared for, or not worth the time and resources required to protect them from ACP and HLB. Untreated citrus can serve as a reservoir for ACP and possibly the disease HLB, increasing the risk to other citrus in the area. The Citrus Matters ACT NOW program may be able to assist with tree removal at little or no charge to you. Find more information at: https://citrusmatters.cropscience.bayer.us/commercial-grower/act-program. Or if you need referrals for tree removal services, contact Sandra or Cressida.
ACP-HLB program meetings
The California Citrus Pest & Disease Prevention Committee (CPDPC) is made up of growers and other representatives of the citrus industry, working with the California Department of Agriculture (CDFA) and others. The CPDPC is funded in large part by grower assessments and steers the statewide effort to protect our citrus from ACP and HLB. The full committee meets every other month, with subcommittees meeting in between. All committee and subcommittee meetings are public and open to anyone to attend or listen remotely via computer or phone. Agendas for upcoming meetings and minutes from previous meetings are posted on the CDFA website: https://www.cdfa.ca.gov/citruscommittee/.
Coastal citrus representative needed for CPDPC
There is an opening for a grower representative from the coast to serve on the CPDPC. Be a part of deciding how grower funds are spent to protect our industry. Details can be found here: https://www.cdfa.ca.gov/egov/Press_Releases/Press_Release.asp?PRnum=17-069.
Santa Paula crew boss workshop
On Wednesday, Nov. 29, the Citrus Pest & Disease Prevention Program and California Citrus Mutual are hosting a free train-the-trainer workshop in Santa Paula. This Spanish-only workshop for crew bosses, ranch managers, etc., focuses on preventing human-aided spread of ACP and HLB. It has been approved by the Department of Pesticide Regulation for 2 hours of continuing education in the "other" category. For details see:
https://citrusinsider.org/2017/11/santa-paula-crew-boss-workshop/#more-2956
Feel free to contact your ACP-HLB grower liaisons if you have any questions or need assistance:
Cressida Silvers
(805) 284-3310
and
Sandra Zwaal
(949) 636-7089
- Author: Ben Faber
At a recent meeting for current and prospective avocado growers near Visalia, Yosepha Shahak a retired researcher from Israel's Volcani Institute presented information on photo-selective netting. This netting was an outgrowth of netting that is used in the Mediterranean region to protect crops from frost damage and the unpredictable hail storms that can occur just as fruit might be coming to harvest. Netting is currently used in commercial orchards and vineyards throughout Europe. San Joaquin Valley growers like the idea of frost protection.
Netting over loquats (nespero) in Spain (Espana)
Netting over apples in Australia
Netting for light modification in Israel. Tractors can work here.
Photo-selective netting refers to covering crops by nets having the capacity to selectively filter the intercepted solar radiation, in addition to their protective function. The technology is based on plastic net products into which light dispersive and reflective elements are introduced during manufacturing. These nets are designed to screen various spectral bands of the solar radiation, and/or transform direct light into scattered light. The spectral manipulation intends to specifically promote desired physiological responses, which are light-regulated, while the scattering improves the penetration of the modified light into the inner plant canopy. So, depending on the crop, more and better fruit set, bigger fruit and some other desirable properties. The netting can also substantially reduce evaporative demand and wind damage. This can lead to not only lower water use, but also such water stress related diseases, such as blight caused by Botryosphaeria fungi. Lower evaporative demand and less water application can lead to less salt damage.
A recent additional aspect to the photo-selective nets refers to their effects on pest behavior. The photo-selective netting concept was developed and tested in Israel in ornamental, vegetable and fruit tree crops. It is gradually spreading all over the world, for implementation in different crops, climatic regions and cultivation methods. Applying it to avocado orchards is going to require pruning and keeping trees so that they can be picked and pollinated. And would probably lead to high density orchards.
And how we do pest management – more or less, and maybe not by helicopter?
This might also be the future for how citrus is grown in an HLB environment. 24 sprays a year to control ACP in Florida -Yikes.
A link to a Shahak talk that she gave to Washington state apple growers can be found at:
- Author: Kathy Keatley Garvey
The Asian citrus psyllid, the most devastating threat to the worldwide citrus industry, may have met its match.
In a ground-breaking discovery encompassing six years of research, an international team of scientists led by UC Davis chemical ecologist Walter Leal announced they've identified the sex pheromone of the pest, which feeds on citrus and transmits the bacteria that causes the deadly citrus greening disease known as Huanglongbing (HLB).
Leal, a native of Brazil and a fellow of both the Entomological Society of America and the Entomological Society of Brazil, revealed the discovery during his presentation Dec. 5 at the 10th Annual Brazilian Meeting of Chemical Ecology in Sao Paulo. His team included scientists from UC Davis, University of Sao Paulo, and the Fund for Citrus Protection (FUNDECITRUS) from the state of Sao Paulo.
“Dr. Leal's discovery of the Asian citrus psyllid pheromone is a significant breakthrough in preventing the spread of this serious citrus insect, and may offer a less toxic method for its control,” said integrated pest management specialist Frank Zalom, distinguished professor with the UC Davis Department of Entomology and Nematology and a past president of the Entomological Society of America. He was not involved in the study.
“Having a lure to dramatically improve captures of this psyllid with the conventional sticky traps is a major progress toward integrated pest management,” said Professor Jose Robert Parra of the University of Sao Paulo.
Identifying the sex pheromone proved “complicated and quite a challenge” because of the insect's complex behavior and biology, said Leal, a UC Davis distinguished professor who has discovered the sex pheromones of moths, beetles, bugs, cockroaches, mites and other arthropods. A patent was filed Friday, Dec. 1, and journal publication is pending.
Citrus trees infected with HLB usually die within five years, according to the UC Statewide Integrated Pest Management Program. There is no known cure. “The only way to protect trees is to prevent spread of the HLB pathogen in the first place, by controlling psyllid populations and removing and destroying any infected trees,” UC IPM says on its website.
Native to Asia, the Asian citrus psyllid, Diaphorina ciri, was first detected in the United States in June 1998 in Palm Beach County, Florida, and in California in August 2008 in San Diego County. Scientists discovered HLB in Florida in August 2005, and in Los Angeles in March 2012. The mottled brown insect, about 3 to 4 millimeters long, or about the size of an aphid, is now widespread throughout Southern California and is now found in 26 of the state's 58 counties.
The Asian citrus psyllid, or ACP, feeds on new leaf growth of oranges, lemons, mandarins, grapefruit and other citrus, as well as some related plants. Infected psyllids can transmit the bacterium Candidatus Liberibacter asiaticus, which causes the fatal citrus disease. An early symptom of HLB in citrus is the yellowing of leaves on an individual limb or in a sector of a tree's canopy.
Currently growers are using yellow sticky traps to detect the insect and to monitor the population. “Efficient lures,” Leal said, “are sorely needed for sticky traps, particularly for early ACP detection. Otherwise, growers have to resort to regular sprays to avoid infection given that infected insects from gardens and noncommercial areas migrate to citrus farms.”
Pheromones and other semiochemicals are widely used in agriculture and medical entomology. “Growers use them as lures in trapping systems for monitoring and surveillance, as well as for strategies for controlling populations, such as mating disruption and attraction-and-kill systems,” Leal noted.
Although ACP is present in Arizona and California, the disease itself has not been established, Leal said. “The emphasis is on detection, eradication and limiting the spread of the disease. In Florida, where HLB is widespread, monitoring ACP populations is essential to avoid reinfection after eradication of infected plants.”
The detection of the pest has led to widespread eradication of citrus trees in China, Brazil and the United States. “In Brazil as many as 46.2 million citrus trees, representing 26 percent of the currently planted trees, have been eradicated since the detection of HLB in 2004,” Leal said. “In Florida, HLB has caused severe losses to the citrus industry. This year's production loss is estimated to be about 28 million fewer boxes of oranges than in 2014-2015.”
The announcement of the discovery coincides with the 40th anniversary celebration of FUNDECITRUS in Araraquara, Sao Paolo. “I am delighted that Walter Leal accepted our challenge to work on this project as the lead investigator,” said Juliano Ayres, FUNDECITRUS director. “The combination of his work ethics and qualifications are unparalleled. And, he loves challenges.”
In response to the ACP invasion in California, the California Department of Food and Agriculture (CDFA) has launched an extensive monitoring program to track the distribution of the insect and disease. They check yellow sticky traps in both residential areas and commercial citrus groves, and also test psyllids and leaf samples for the presence of the pathogen.
Survey methods for ACP include visual inspections, sweep netting, and placement of yellow sticky traps in trees in citrus nurseries, commercial citrus-producing areas and residential properties throughout the state, according to the CDFA. They also place sticky traps in California fruit packing houses, specialty markets, retail stores and airports that receive such produce from areas known to be infested with ACP.
Since August 2008, ACP has now been detected in 26 of California's 58 counties: Alameda, Contra Costa, Fresno, Imperial, Kern, Kings, Los Angeles, Madera, Merced, Monterey, Orange, Placer, Riverside, San Benito, San Bernardino, San Diego, San Joaquin, San Luis Obispo, San Mateo, Santa Barbara, Santa Clara, Solano, Stanislaus, Tulare, Ventura, and Yolo. “The ACP has the potential to establish itself throughout California wherever citrus is grown,” the CDFA says on its website.
CDFA has set up a hotline at 1-800-491-1899 for residents to report suspicious insects or disease symptoms in their citrus trees.
Resources:
UC IPM|
http://ipm.ucanr.edu/PMG/r107304411.html
California Department of Food and Agriculture (CDFA)
https://www.cdfa.ca.gov/plant/PDEP/target_pest_disease_profiles/ACP_PestProfile.html
Save Our Citrus: Hotline Information
UC Agriculture and Natural Resources (UC ANR)
http://anrcatalog.ucanr.edu/pdf/8205.pdf
- Author: Ben Faber
HLB confirmations The number of trees in Southern California confirmed to be infected with HLB has risen to 347, distributed across 16 communities in four counties. So far, all are in residential plantings, not in commercial groves. As HLB detections increase and spread closer to commercial citrus, it is a good time to consider removing citrus trees that are uncared for or not worth the resources required to protect them from ACP and HLB. The distribution of HLB confirmations, updated weekly, can be found on https://citrusinsider.org/maps/. Winter ACP area-wide cycle As a reminder, due to the Thomas Fire the treatment window for psyllid management areas in West Ventura and the Ojai Valley (PMAs 44-50) was delayed until Feb. 23-March 16. If you wish to confirm your treatment window or interim treatment percentages, or obtain referrals for pest-control or tree-removal services, 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 Citrus Matters ACT NOW program. More information can be found at https://citrusmatters.cropscience.bayer.us/commercial-grower/act-program. HLB in the news ABC7 news and The San Bernardino Sun recently picked up a story regarding a San Bernardino County nursery caught up in the HLB quarantine, which led to destruction of its inventory of citrus trees. ABC News7 article with clip: http://abc7.com/food/ie-nurserys-citrus-trees-to-be-destroyed-by-ca-agriculture-department/2959173/ The Sun article: https://www.sbsun.com/2018/01/19/more-than-4000-citrus-trees-destroyed-while-disagreement-between-bloomington-nurseries-state-continues/ Meetings UC Riverside & Citrus Research Board Citrus Day for the Industry will be on Tuesday, Feb. 6, at UC Riverside. The deadline to register is Jan. 30. Registration is $35 and includes lunch. Online registration is available at https://form.jotform.com/80016278039152. Click here to download the program. The Citrus Pest and Disease Prevention Committee's operations and outreach subcommittees will meet Wednesday, Feb. 7, at the Mission Inn Hotel in Riverside. Attendance is free. The CDFA website with agenda, venue, and webinar information is at https://www.cdfa.ca.gov/citruscommittee/. If you have any questions, please contact one of the grower liaisons: Cressida Silvers (805) 284-3310 Sandra Zwaal (949) 636-7089 |