- Author: Ben Faber
EMPLOYMENT OPPORTUNITY
University of California
Hansen Agricultural Research
and Extension Center
Position: Farm Supervisor
Posting Salary: $53,800 – $79,800/yr.
County Location: Santa Paula, Ventura County
Date Posted: September 4, 2019
Closing Date: September 21, 2019
The Hansen Agricultural Research and Extension Center (HAREC) located in Ventura County provides land, labor and facilities for research that supports the rich and diverse agricultural and natural resources of Ventura County and an extensive education program that promotes the sustainability and benefits of agriculture and natural resources in county communities. The HAREC facility encompasses 27 acres including demonstration gardens, orchards, research fields, a small greenhouse, as well as a historical barn and Queen-Anne Victorian house.
Under the direction of the Center Director, this position is responsible for the management, planning and implementation of field research, farming operations, physical plant operations, grounds and building maintenance, irrigation, and related administrative functions. Responsibilities also include participating in logistical planning and implementation of extension activities. Responsibilities include training and supervising field staff to maintain an orderly, safe, and efficient operation, and is responsible for staff annual performance evaluations. This position will serve as a member of the Center's executive management team and is expected to participate in facilities planning and budgeting, including providing recommendations regarding infrastructure, resources, and staffing needs.
This position includes verbal and written communication to staff, vendors, contractors, and other parties in Spanish.
This position will end after one year. Extension beyond this date is contingent on budgetary and/or operational considerations.
This position will promote, in all ways consistent with the other responsibilities of the position, accomplishment of the Affirmative Action goals established by the Division.
For further details and to apply please copy and paste this web link on to a URL:
https://jobs.ucop.edu/applicants/Central?quickFind=61996
"The University of California is an Equal Opportunity/Affirmative Action Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability, age, protected veteran status or other protected categories covered by the UC nondiscrimination policy."
/h2>/h2>/h1>/h1>/h1>/h1>- Author: Ben Faber
A “boring” problem that's generating
big interest in southern California
By Deena Husein, UCR Entomology, Ph.D. Candidate, Stouthamer Lab, UC Riverside
It has been a little over a decade since the first sighting of the polyphagous shot hole borer (PSHB) in Los Angeles County, yet a reliable control method has not been established. Part of the setback was caused by the misidentification of the species due to the beetle having a similar appearance to a low-risk pest — the tea shot hole borer. Aside from Los Angeles County, the PSHB is now established in Ventura, Orange, Riverside, San Bernardino and Santa Barbara Counties. We should be very alarmed at the rate the beetle has spread in southern California! The PSHB bores tunnels, also called galleries, in the xylem of the plant host and compromises the water transportation system. Tissue damage on the plant host is not only caused by the boring action alone, but also by the symbiotic, yet pathogenic, fungi the beetles carry to inoculate the gallery walls and utilize as a food resource. Consequently, the fungal buildup obstructs more water from reaching the branches, which can lead to dieback symptoms and eventually the mortality of the tree. The underlying issue lies in the gradual increase of plant species susceptible to being attacked. Currently, there are over 300 plants, 60 of which the beetle can reproduce on, including several native oaks, maples, sycamores, and willows along with ornamental plants and major agricultural crops (avocado) (Eskalen et al. 2013). A study by McPherson et al. 2017 showed that 23.2 million trees (32.8%) of southern California's region are susceptible to attacks by the PSHB beetle. Should half become infested, the approximate cost of removing and replacing those trees will be $15.9 billion with an annual accruement of $616.9 million over the next 10 years. The damage and loss the beetles have already costed the state will only continue to rise without the establishment of an effective management program.
We understand that this pest is a major threat to the forestry and agricultural industry, but what efforts have been made to stop it? So far, conventional methods such as pesticides and mate disruption through pheromone traps have been rendered ineffective due to the beetle's cryptic lifestyle. The PSHB mates prior to leaving its natal gallery and is only outside for a brief period of time spent entirely on finding a suitable plant host. With that in mind, our laboratory has taken a different course of action that focuses entirely on biological control. Analyses of beetles sampled worldwide paved the path to a foreign exploration trip to Taiwan in the hopes of finding promising natural enemies of the PSBH. Since we are dealing with a wood boring beetle that remains hidden inside of its host, the best approach to encounter any natural enemy is by collecting beetle-infested plant material such as logs. The collection sites can be seen on the map below, all of which were in the district of Tainan City. Infested logs were shipped to the Insectary and Quarantine facility located at the University of California, Riverside (Figure 1A). From there, logs were individually placed in separate containers and monitored daily for anything that emerged (Figure 1B). After three trips and many logs later, we were able to identify three promising parasitoid wasps and two fungal-feeding nematodes associated with the PSHB.
The first parasitoid wasp we have encountered belongs in the family Bethylidae (Figure 2). A closely related species in the same genus has been documented to parasitize the coffee berry borer, another invasive pest with a similar lifestyle to the PSHB. While breaking apart some of the logs, we were able to find parasitized beetles with silk cocoons extending from their heads. Inside one of these cocoons was a bethylid pupa, which looks very promising (Figure 3). The second parasitoid is a braconid with an interesting method of attack. This novel species in the genus Sinuatophorus has prominent and large mandibles to 1) remove any excess material, such as frass and sawdust, at the entrance of the beetle gallery then 2) clasp the head of the beetle and eventually parasitize it. However, most taxonomic descriptions of wasps in this genus always cite Seitner and Notzel's publication from 1925, which mainly focuses on the development and lifecycle of another closely related wasp in a different genus. This poses as a challenge since our understanding of the lifecycle of this novel wasp is limited. Despite this setback, we were able to rear 4 generations by reintroducing every newly emerged wasp to multiple PSHB-infested castor bean logs.
The third parasitoid belongs to a very small, yet unique, group. Not only does this wasp attack beetles in their adult stage, but it also lays two eggs: one male and one female. Once fully developed, the female chews a hole from the inside of the abdomen and creates an exit path for herself and the male wasp. But the excitement doesn't stop there! While rearing beetles that emerged from the shipped logs, we were able to come across multiple nematodes. While most of them appeared harmless, some were categorized as fungal feeders. By introducing these fungal-feeding nematodes to beetle galleries, we could potentially use them as an indirect approach to mitigate the population of the beetles by attacking their food supply.
We have come pretty far in the past three years and are now able to narrow our efforts on these natural enemies. Though, as is the case with most biological control programs, there are many challenges and failures that will be faced. Our biggest hurdle to overcome is the cryptic lifestyle of the beetle. Once we introduce newly emerged wasps to beetle-infested logs, any control we have over the rearing process is taken away. Basically, this becomes a black box with no way of observing any parasitization occurring inside without breaking into the logs and jeopardize killing the insects by accident. We are currently trying to improve our rearing methods in the hopes of increasing our wasp colony size. Eventually with large numbers, we can move forward with non-target testing and come to a decision on whether or not we can utilize these natural enemies as a biological control agents to suppress the PSHB population.
Map: collection sites of PSHB beetle-infested avocado logs from Tainan City, Taiwan.
Figure 1A (left): Bag with beetle-infested avocado logs from Taiwan. Figure 1B (right): Temperature-controlled room with logs separated in plastic containers in the Insectary and Quarantine facility at UCR.
Figure 2:Image taken of Bethylid adult that emerged from beetle-infested avocado logs collected from Taiwan. Credit: Iris Chien
Figure 3 (top): Parasitized PSHB found with a silk cocoon extended from the head of the beetle. Bottom:A cocoon was dissected, adjacent from the intact cocoon, with a visible bethylid pupa.
Read and see more at:
http://ceventura.ucanr.edu/newsletters/Topics_in_Subtropics80946.pdf
Literature Cited:
Eskalen, A., Stouthamer, R., Lynch, S. C., Rugman-Jones, P. F., Twizeyimana, M.,
Gonzalez, A., and Thibault, T. (2013). Host range of Fusarium dieback and its
ambrosia beetle (Coleoptera: Scolytinae) vector in Southern California. Plant Dis,
97(7), 938–951.
McPherson, G., Xiao, Q., Van Doorn, N. S., De Goede, L., Bjorkman, J., Hollander, A., Boynton, R. M., Quinn, J. F., and Thorne, J. H. (2017) The structure, function and value of urban forests in California communities.Urban Forestry & Urban Gardening 28: 43-53.
Seitner, M. and Notzl, P. (1925). Pityophthorus Henscheli Seitner und sein Parasit
Cosrnophorus Henscheli Ruschka.
- Author: Ben Faber
BUFFALO, N.Y. -- We now know the DNA of guacamole. A repost from: https://www.eurekalert.org/pub_releases/2019-08/uab-glr080619.php
Scientists have sequenced the avocado genome, shedding light on the ancient origins of this buttery fruit and laying the groundwork for future improvements to farming.
With regard to modern affairs, the study reveals for the first time that the popular Hass avocado inherited about 61 percent of its DNA from Mexican varieties and about 39 percent from Guatemalan ones. (Avocados come in many types, but Hass -- first planted in the 1920s -- comprises the bulk of avocados grown around the world.)
The research also provides vital reference material for learning about the function of individual avocado genes, and for using genetic engineering to boost productivity of avocado trees, improve disease resistance and create fruit with new tastes and textures.
The study is important for agriculture. The growing global market for avocados was worth about $13 billion in 2017, with Mexico, the largest producer, exporting some $2.5 billion worth of the fruit that year, according to Statista, a provider of market and consumer data. Around the world, avocados are spread on tortillas, mashed up to flavor toast, rolled into sushi and blended into milkshakes (a popular treat in parts of Southeast Asia).
Scientists sequenced not only the Hass avocado, but also avocados from Mexico, Guatemala and the West Indies, which are each home to genetically distinct, native cultivars of the fruit.
The project was led by the National Laboratory of Genomics for Biodiversity (LANGEBIO) in Mexico, Texas Tech University, and the University at Buffalo. The research was published on Aug. 6 in the Proceedings of the National Academy of Sciences.
"Avocado is a crop of enormous importance globally, but particularly to Mexico. Although most people will have only tasted Hass or a couple of other types, there are a huge number of great avocado varieties in the species' Mexican center of diversity, but few people will have tried them unless they travel south of the U.S. border. These varieties are genetic resources for avocado's future. We needed to sequence the avocado genome to make the species accessible to modern genomic-assisted breeding efforts," says Luis Herrera-Estrella, PhD, President's Distinguished Professor of Plant Genomics at Texas Tech University, who conceived of the study and completed much of the work at LANGEBIO, where he is Emeritus Professor, prior to joining Texas Tech University.
"Our study sets the stage for understanding disease resistance for all avocados," says Victor Albert, PhD, Empire Innovation Professor of Biological Sciences in the UB College of Arts and Sciences and a Visiting Professor at Nanyang Technological University, Singapore (NTU Singapore). Albert was another leader of the study with Herrera-Estrella. "If you have an interesting tree that looks like it's good at resisting fungus, you can go in and look for genes that are particularly active in this avocado. If you can identify the genes that control resistance, and if you know where they are in the genome, you can try to change their regulation. There's major interest in developing disease-resistant rootstock on which elite cultivars are grafted."
The family history of an eccentric, big-pitted fruit
While the avocado rose to international popularity only in the 20th century, it has a storied history as a source of sustenance in Central America and South America, where it has long been a feature of local cuisines. Hundreds of years ago, for example, Aztecs mashed up avocados to make a sauce called āhuacamolli.
Before that, in prehistoric times, avocados, with their megapits, may have been eaten by megafauna like giant sloths. (It's thought that these animals could have helped to disperse avocados by pooping out the seeds in distant locations, Albert says.)
The new study peers even further back into time. It uses genomics to investigate the family history of the avocado, known to scientists as Persea americana. "We study the genomic past of avocado to design the future of this strategic crop for Mexico," Herrera-Estrella said. "The long life cycle of avocado makes breeding programs difficult, so genomic tools will make it possible to create faster and more effective breeding programs for the improvement of this increasingly popular fruit."
The avocado belongs to a relatively small group of plants called magnoliids, which diverged from other flowering plant species about 150 million years ago. The new research supports -- but does not prove -- the hypothesis that magnoliids, as a group, predate the two dominant lineages of flowering plants alive today, the eudicots and monocots. (If this is right, it would not mean that avocados themselves are older than eudicots and monocots, but that avocados belong to a hereditary line that split off from other flowering plants before the eudicots and monocots did.)
"One of the things that we did in the paper was try to solve the issue of what is the relationship of avocados to other major flowering plants? And this turned out to be a tough question," Albert says. "Because magnoliids diverged from other major flowering plant groups so rapidly and so early on, at a time when other major groups were also diverging, the whole thing is totally damn mysterious. We made contributions toward finding an answer by comparing the avocado genome to the genomes of other plant species, but we did not arrive at a firm conclusion."
Magnoliids were estimated by a 2016 research paper to encompass about 11,000 known living species on Earth, including avocados, magnolias and cinnamon. In comparison, some 285,000 known species were counted as eudicots and monocots.
The avocado as a chemist, and the heritage of the hybrid Hass
Scientists don't know how old the avocado is, and the new study doesn't address this question. But the research does explore how the avocado has changed -- genetically -- since it became its own species, branching off from other magnoliids.
The paper shows that the avocado experienced two ancient "polyploidy" events, in which the organism's entire genome got copied. Many of the duplicated genes were eventually deleted. But some went on to develop new and useful functions, and these genes are still found in the avocado today. Among them, genes involved in regulating DNA transcription, a process critical to regulating other genes, are overrepresented.
The research also finds that avocados have leveraged a second class of copied genes -- tandem duplicates -- for purposes that may include manufacturing chemicals to ward off fungal attacks. (Tandem duplicates are the product of isolated events in which an individual gene gets replicated by mistake during reproduction.)
"In the avocado, we see a common story: Two methods of gene duplication resulting in very different functional results over deep time," Albert says.
"In plants, genes retained from polyploidy events often have to do with big regulatory things. And genes kept from the more limited one-off duplication events often have to do with biosynthetic pathways where you're making these chemicals -- flavors, chemicals that attract insects, chemicals that fight off fungi. Plants are excellent chemists," Herrera-Estrella says.
Having addressed some ancient mysteries of the avocado, the new study also moves forward in time to explore a modern chapter in the story of this beloved fruit: how humans have altered the species' DNA.
Because commercial growers typically cultivate avocados by grafting branches of existing trees onto new rootstocks, today's Hass avocados are genetically the same as the first Hass avocado planted in the 1920s. These modern-day Hass avocados are grown on Hass branches grafted onto various rootstock that are well adapted for particular geographic regions.
While the Hass avocado was long thought to be a hybrid, the details of its provenance -- 61 percent Mexican, 39 percent Guatemalan -- were not previously known. The scientists' new map of the Hass avocado genome reveals huge chunks of contiguous DNA from each parental type, reflecting the cultivar's recent origin.
"Immediately after hybridization, you get these giant blocks of DNA from the parent plants," Herrera-Estrella says. "These blocks break up over many generations as you have more reproductive events that scramble the chromosomes. But we don't see this scrambling in the Hass avocado. On chromosome 4, one whole arm appears to be Guatemalan, while the other is Mexican. We see big chunks of DNA in the Hass avocado that reflect its heritage."
"We hope that the Mexican Government keeps supporting these types of ambitious projects that use state-of-the-art technology to provide a deep understanding of the genetics and genomics of native Mexican plants," Herrera-Estrella said.
###
In addition to LANGEBIO, UB and Texas Tech University, the avocado genome sequencing team included scientists from the Swedish University of Agricultural Sciences; Instituto de Ecología, A.C.; Universidad Nacional Autónoma de México; Nanyang Technological University; University of Ottawa; VIB-UGent Center for Plant Systems Biology; Universidad de Guanajuato; University of Florida; University of Nevada, Reno; Queensland Alliance for Agriculture and Food Innovation; Universitat de Barcelona; USDA-ARS Subtropical Horticulture Research Station; Universidad Autónoma Chapingo; Natural History Museum of Denmark; and Université Paul Sabatier.
The research was funded by SAGARPA/CONACYT, the Governors University Research Initiative of the State of Texas, the U.S. National Science Foundation, Horticulture Innovation Australia Ltd. and the Australian Bureau of Agricultural and Resource Economics and Sciences.
- Author: Ben Faber
A team of dogs trained to identify Huanglongbing-infected citrus trees by scent has detected evidence of early HLB infection in commercial groves in Ventura County.
The canine visit was arranged on behalf of the ACP-HLB Task Force by Farm Bureau of Ventura County, which signed a contract with the commercial company that trains and manages the dog teams. Four dogs and two handlers from F1K9, along with the company's operations manager, departed from Florida on July 24 and arrived in Ventura on July 26. Grove scouting began July 29 and ended Aug. 1.
During that time, the team inspected approximately 3,500 trees on 20 ranches in three major citrus production areas: the Las Posas Valley, the Santa Clara River valley, and the Ojai Valley. The dogs alerted on 211 trees, indicating early HLB infection is present in all three areas.
In preparation for the scouting visit, we prioritized potential locations on the basis of four criteria:(1) the presence of "hot spots" where plant and/or ACP samples yielded inconclusive DNA test results during the California Department of Food and Agriculture's periodic HLB surveys; (2) proximity to major transportation arteries; (3) a long history of established Asian citrus psyllid populations; and (4) a low level of participation in ACP suppression efforts by both growers and homeowners.
We also sought volunteers who would allow their ranches to be scouted, agree to pay for the cost (about $4.50 per tree), and agree to remove suspect trees. We agreed to keep the specific locations confidential unless granted permission to share that information by the owner.
The ranches the dogs scouted included one west of Fillmore along Highway 126, one west of Santa Paula without highway frontage, eight at the east end of the Ojai Valley, one outside of Moorpark along Highway 23, one north of Somis without highway frontage, and nine along a 4-mile stretch of Highway 118 west of Somis.
The dogs alerted on a single tree at one of the eight ranches they scouted in the Ojai Valley. Dogs indicated early HLB infection in multiple trees at every other location they scouted.
Although more than 1,600 HLB-infected trees have been confirmed and removed in urban yards in Los Angeles, Orange and Riverside counties, the recent dog alerts here are the first evidence of widespread HLB infection in commercial citrus in California. It is also the first time this early detection technique (EDT) has been deployed for non-experimental purposes, as a tool for commercial growers to make decisions about tree removal to potentially eliminate sources of infection and halt or delay the epidemic's spread. (Up-to-date summaries of the HLB epidemic can be found here: https://www.datoc.us/the-hlb-epidemic).
Because neither the U.S. Department of Agriculture nor the California Department of Food and Agriculture recognize dog alerts as direct proof of the presence of the causal agent of HLB, the canine alerts do not trigger regulatory action. This allows growers to remove suspect trees voluntarily without the complications and cost associated with quarantine requirements that would be triggered by confirmation through official DNA testing.
Despite their non-regulatory status, the dogs' ability to accurately identify early HLB infection in citrus trees has been scientifically demonstrated and validated. The four canines that traveled to Ventura County last month are part of a 19-dog group trained to detect HLB through a multi-year research and development program funded by the U.S. Department of Agriculture and overseen by Dr. Tim Gottwald at the USDA research station in Fort Pierce, Fla. Dr. Gottwald has presented updates on the project at the last four International Research Conferences on HLB, including the most recent one this year in Riverside, as well as at many other scientific gatherings. One of his presentations on the project is available to view online.
The dog's indication of early HLB infection in local commercial groves is a watershed moment in the history of Ventura County's citrus industry. We've long known this day would come, but that doesn't prevent the news from landing as a gut punch. The knowledge we are gaining through strategic deployment of the canine team, however, gives growers here a fighting chance to stem the epidemic's spread while there is still time to do so
And so far, the distribution pattern of dog-alert trees - in general, widely scattered along grove perimeters - suggests we may be catching the epidemic in its very early stages. If this proves to be the case countywide, prompt tree removal and a zero-tolerance policy toward the Asian citrus psyllid - meaning total commitment to the ACP-suppression treatment program - may buy us years of continued viability and profitability even in the face of this threat.
To that point, it is more critical than ever for ACP to be well-controlled: No psyllids means no spread of disease. Growers should continue to treat when asked to for the area-wide treatments. But in addition, Dr. Beth Grafton-Cardwell of UC Riverside now recommends that perimeters be scouted every two weeks, and if psyllid eggs or nymphs are found, that the orchard be treated immediately. These additional treatments, above and beyond the area-wide treatments, must be applied whenever psyllids are found, to keep ACP suppressed below detectable levels.
We are planning to bring the dogs back out for additional scouting as soon as it is feasible. We need to visit other areas that meet the risk-factor prioritization test, so we can establish a baseline picture of how HLB is distributed throughout the county. This will help guide our ACP-suppression and HLB-eradication strategy going forward.
Potential participants are welcome to contact Farm Bureau CEO John Krist for inclusion on the list of properties prioritized for future scouting, so long as they are willing to pay for the cost (currently estimated at about $4.50 per tree), and agree to remove suspect trees. The dogs' time is too valuable and their availability too limited to deploy them where the information they provide won't be acted upon. Ultimately, our intent is to have a team based here permanently, but that will take time and money. We're exploring ways to make it happen.
For a full report on the Ventura County scouting visit, including documents describing the scientific basis of the canine program, go to http://bit.ly/HLB-K9
- Author: Ben Faber
The 2019 Pitahaya/Dragon Fruit Festival/Field Day
Saturday, September 14, 2019
Located at the UC South Coast Research & Extension Center
1601 Irvine Boulevard, Irvine, CA 92618
6:30am - 2:30pm
Please join us as we discuss how to grow a pitahaya from a seed, irrigation and design considerations, weed management strategies without glyphosate, nematode issues, and much more! To view the entire agenda, click here. We expect this Festival to sell out, so register early!
Registration is $40.00 per person if paid online or postmarked by Monday, September 9, 2019. The price will be $50.00 after this date or at the door, if space allows (checks only at the door). Register early as attendance is only limited to 100 participants. Click here to continue on with registering.
Registration fee includes continental breakfast, lunch, pitahaya or dragon fruit ice cream tasting, and an informational packet.
Please Note: refunds will not be issued, but substitutions are allowed.
For questions regarding registration and substitutions, please contact Erin Spaniel at 858-822-7919. For general program information, please contact Ramiro Lobo at 858-243-4608.