Posts Tagged: HLB
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:
Task Force ACP-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.
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:
Feel free to contact your ACP-HLB grower liaisons if you have any questions or need assistance:
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
The California Department of Food and Agriculture (CDFA) and the United States Department of Agriculture (USDA) have confirmed the detection of the citrus disease known as Huanglongbing (HLB), or citrus greening, in Riverside County. The disease was detected in plant material taken from a grapefruit tree in a residential neighborhood in the city of Riverside near I-215.
The infected tree has been removed and agriculture officials are moving swiftly on mandatory surveying in an 800-meter area. Mandatory treatments will soon follow. CDFA staff will visit all regulated entities in the quarantine area, including retail and production nurseries and packinghouses. Additionally, local, state and federal agriculture authorities are working together to determine potential implications to the University of California, Riverside, which will fall within the 5-mile quarantine area.
Riverside County Agricultural Commissioner/Sealer Ruben Arroyo plans to take an aggressive stance on any abandoned groves in the area, and the Citrus Pest & Disease Prevention Program outreach team is already working with the City of Riverside to inform residents of the actions needed to stop HLB's spread.
Please read the full press release shared on July 25 by Riverside County.
For more information about ACP or HLB, Riverside County residents may call the Agricultural Commissioner's Office at (951) 955-3045 or CDFA's toll-free pest hotline at 1-800-491-1899 or visit: www.cdfa.ca.gov/plant/acp//span>
California citrus farmers have their ears perked for all news related to Asian citrus psyllid (ACP) and huanglongbing (HLB) disease, but the very latest advances have been available only in highly technical research journals, often by subscription only.
UC Cooperative Extension scientists are now translating the high science into readable summaries and posting them on a new website called Science for Citrus Health to inform farmers, the media and interested members of the public.
“The future of the California citrus depends on scientists finding a solution to this pest and disease before they destroy the industry,” said Beth Grafton-Cardwell, UC Cooperative Extension citrus entomology specialist. “Our farmers want to stay on top of all the efforts to stop this threat.”
Grafton-Cardwell and UC Cooperative Extension biotechnology specialist Peggy Lemaux are the two scientists behind the new website. When scientists make progress toward their goals, Grafton-Cardwell and Lemaux craft one-page summaries with graphics and pictures to provide readers with the basics.
For example, the website outlines scientific endeavors aimed at stopping the spread of huanglongbing disease by eliminating the psyllid's ability to transfer the bacterial infection. This section is titled NuPsyllid, and contains summaries of three research papers including one by UC Davis plant pathologist Bryce Falk.
Falk is collecting viruses found in Asian citrus psyllid; so far he has identified five. He is looking into the potential to utilize one of the viruses as is or modify one of the viruses to block the psyllid's ability to transmit the bacterium. For example, the virus might out compete the bacterium in the psyllid's body.
Another focus of the website is HLB early detection techniques (EDTs). If HLB-infected trees are found and destroyed before they show symptoms, ACP is less likely to spread the disease to other trees. EDT research described on the website includes efforts to detect subtle changes in the tree that take place soon after infection, such as alterations in the scents that waft from the tree (studied by UC Davis engineer Cristina Davis), changes in the proteins in the tree (studied by UC Davis food scientist Carolyn Slupsky) and starch accumulation in the leaves (studied by UC farm advisor Ali Pourreza).
As more research is published, more one-page descriptions will be added to the website. The website contains a feedback form to comment on the science and the summaries.
Photo: ACP traps