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Posts Tagged: food
Almond growers should prepare for possibility of unusual disease outbreak
Wet winter, El Niño create favorable conditions for aerial Phytophthora pathogen
With heavy rains in the forecast amid strengthening El Niño conditions, almond growers should be on the lookout for a rare disease that can cause severe damage to their orchards, according to Florent Trouillas, a University of California Cooperative Extension specialist in fruit and nut pathology.
Phytophthora, soilborne microorganisms dubbed “water molds” because of their dependence on water, typically cause root and crown rot at the base of trees. But a few aerial Phytophthora can travel upwards and infect the higher parts of the tree. One species – Phytophthora syringae – is drawing special attention due to an unprecedented outbreak last winter, fueled by the atmospheric rivers that lashed California.
“It was found statewide – meaning in every almond-producing county – and disease incidence in orchards ranged from 10% of the trees infected to 75%,” said Trouillas, a UC Davis plant pathologist whose lab is based at UC Agriculture and Natural Resources' Kearney Agricultural Research and Extension Center in Parlier.
Trouillas and his colleagues, UC Davis graduate student Alejandro Hernandez and UC Riverside plant pathology professor Jim Adaskaveg, recently published a detailed online article describing the pathogen, which can infect a range of crops but mainly impacts almonds in California.
Although it doesn't kill the tree, the disease causes branch dieback that requires significant additional work and expense for almond growers. In 2022, almonds were the state's fourth-highest valued commodity, at $3.52 billion.
During last year's aerial Phytophthora outbreak, researchers also observed a new and troubling phenomenon: P. syringae, historically known to attack the cuts caused by pruning, was directly infecting the young shoots on almond trees – without any wounds.
“This was really the first time we had seen widespread evidence of infection on the twigs,” Trouillas said.
Although generally rare, outbreaks of P. syringae have been traditionally associated with wet El Niño years, according to Trouillas – and recent and persistent rain across the state should have growers on high alert.
Prune in dry weather, monitor, mitigate if necessary
While almond growers tend to prune during the downtime of winter, they should keep an eye on the forecast and aim for a 10- to 14-day window of dry weather to perform those tasks, whether training young trees or maintaining the established ones.
“If growers were to prune around a rain event – before, during or shortly after – this increases the likelihood of infection because this pathogen moves around with water,” Trouillas explained.
Researchers speculate that P. syringae, normally found in the soil, gets carried into the upper parts of a tree through strong winds and heavy rain. Alternatively, harvest processes like shaking and sweeping also produce air movements that may blow the microorganism into the canopy, where it waits for a favorable wet environment. The pathogen then attacks the wounds or young shoots, producing characteristic cankers and gumming.
The patterns and colors of the gum balls are keys to diagnosing an infection of this particular aerial Phytophthora. Starting around bloom time (mid-February), growers should monitor pruning wounds and young shoots on their trees, especially in the canopy, for signs of the disease.
The unique coloration of the gum balls – ranging from gold and amber to dark burgundy to bright red (see photos) – generally indicates P. syringae infection. But growers are urged to contact their local Cooperative Extension advisor for confirmation.
“It is super critical for growers that, whenever they see gumming, not to assume that it is this aerial phytophthora, because there are many other diseases that can cause gumming on the tree,” Trouillas said.
If the diagnosis is confirmed, growers may apply a compound that can mitigate the infection. The plant pathologists' recent writeup describes several curative treatment options, as well as a preventive measure that reduces the amount of pathogen in the soil and thus the likelihood of infection.
For more information on the pathogen's history and biology, as well as various options for disease management, visit the article on Sacramento Valley Orchard Source: https://www.sacvalleyorchards.com/almonds/trunk-soil-diseases/aerial-phytophthora-outbreaks-in-wet-years.
UCCE advisor Bruno guides, learns from dairies switching to milking robots
Automatic milking systems increasingly used in California amid labor challenges
When third-generation dairy farmer Shonda Reid first saw a milking robot at a farm show 13 years ago, she immediately recognized that the technology represented the future. Her father, however, took a bit more convincing.
“I came home and showed him and said, ‘This is what we need to do.' And he thought I was kidding!” said Reid, dairy and farm manager for Fred Rau Dairy, which has a herd of 1,400 milk cows in Fresno County.
Years later, after the family had visited several dairies using automatic milking systems (AMS) across the U.S., they installed their first six robots in November 2021. By fall 2022, they had 24 robots, evenly split between two newly built “free stall” barns where the cows can freely go to the milking machines.
As Fred Rau Dairy was one of the first in California to implement AMS at such a scale, Reid and her team have been instrumental in growing practical knowledge on these systems. She also has been a valued partner to Daniela Bruno, University of California Cooperative Extension dairy advisor for Fresno, Madera and Kings counties.
“Automatic milking robots are not a new technology, but it's new to California,” said Bruno, noting that the milking robots were first used on small, family-run farms in Europe, where the technology granted family members more time for rest and other pursuits.
To better understand the feasibility of milking robots for large dairies in California, Bruno – alongside former UC Davis School of Veterinary Medicine professor Fernanda Ferreira, University of Minnesota researcher Marcia Endres and other collaborators – began a project in 2020 to study the risks and opportunities of automated systems.
“The information is extremely useful for California producers to make informed decisions about implementing AMS on their facilities,” said Denise Mullinax, executive director of the California Dairy Research Foundation, which supported the effort through a competitive grant. “Cow care, labor requirements and profitability are key issues for producers, and CDRF was pleased to support this project which assists producers in understanding how AMS may impact those areas on their facility.”
Dairy farmer: ‘We needed to make some changes'
The project produced a paper analyzing existing research on automatic systems, which have been more widely used in the Midwest, where there are more small-scale, family-run dairies. In 2020, there were only 14 “box robots” in California, according to Bruno. Now there are about 200 across California – and both Bruno and Reid cited labor challenges as the primary reason for the increased use of automated systems.
“California suffers from labor quality and quantity issues,” Bruno said. “By bringing robots to California, you can minimize those problems.”
Higher costs of hiring and retaining employees, driven in part by new labor laws, are one factor. And then there's the reliability and availability of labor, as fewer people are willing to do the physically demanding work of conventional milking.
“People just don't want to milk in a flat barn [a conventional setup where the employee works at the same level as the cow] – there's a lot of kneeling, squatting, that type of thing – it's pretty tough on the body,” Reid explained.
Faced with labor shortages and mounting regulatory burdens, Reid said Fred Rau Dairy had to make the leap to automated systems to keep the 80-year-old dairy operation running.
“We needed to make some changes, or we're going out of the dairy business,” she said.
In a survey conducted by Bruno and her colleagues of large dairies using AMS across the U.S., a majority of the 29 respondents reported reductions in labor costs – but survey results did not offer a definitive picture on whether AMS improved bottom-line profitability.
Calmer, healthier cows
Nevertheless, most of the survey respondents said they were generally happy with their transition to automatic systems.
“It's totally met our expectations, and cow health has gotten much better, too,” Reid said.
In a typical conventional system where cows are outside in “open corral” pens, dairy employees must cajole the cows into the milking parlor. But within a “free stall” barn where the cows can voluntarily go to the milking robots when they want, as often as they want, the animals are much less stressed.
“When you think about cow handling, if you have robots, you don't have anybody pushing and screaming at them to walk to the parlor,” Bruno explained. “You have less cow-people interaction so they are more calm; there is less stress.”
In the survey of large dairies using milking robots, more than 90% of the respondents said their cows were calmer. Reid also noted that many people have noticed how calm their cows are in the free stall barns.
“They're not skittish, you can walk in and they don't run,” Reid said. “They'll just watch you or they'll even come up and start licking on your jacket or shirt.”
Bruno also said that many of the large dairies reported fewer cases of mastitis and other diseases, less lameness, and greater milk production. But she added it's hard to know whether the benefits can be attributed to the robots and their real-time monitoring technology – or to changes in the physical environment (cows save energy in the free stall barn setup, versus the open-corral system that requires walking to the milking parlor).
Dairy producers seek counsel on potential transition
Less bovine travel from outside to inside was a boon for Fred Rau Dairy during last year's unusually wet winter.
“Even if it's just a couple of weeks of rain, that mud and manure and everything – you do what you can, but oh my gosh – it's a mess,” said Reid, noting that easier facility maintenance during extreme weather was another benefit of switching to automatic systems within free stall barns.
Reid shared many of her experiences with attendees of an AMS Field Day in October 2022, arranged by Bruno, Ferreira and their collaborators. About 60 farmers, researchers, industry representatives and consultants visited Fred Rau Dairy and Jones Dairy in Merced County.
If a dairy producer is considering implementing automatic systems, Reid recommends that they research all their options, visit dairies that use the systems, and check who in their area would be providing service and technical support.
And there are crucial workforce considerations, as dairy workers must learn an entirely new set of skills and processes. Instead of spending their time fetching the cows, prepping them and milking them in the parlor, workers might need to gather and interpret data from the robots. “Cow people,” as Reid puts it, must become computer people.
“You have a group of people who have been with you for a while, and you hope that they can transition to the new technology of what you're doing,” Reid said.
During this technological transition, and on the myriad other challenges that dairy operators face, Reid said she is grateful for Bruno's expertise and responsiveness.
“If there's something that I need, she's been really good about trying to help – or putting me in contact with the right people,” she explained. “I've enjoyed working with her.”
The AMS project team also includes UC Davis School of Veterinary Medicine professor Fabio Lima, postdoctoral researcher Thaisa Marques and former postdoctoral researcher Camila Lage.
No-till annual wheat better for soil health in California’s climate
One more reason to adopt sustainable cultivation
California wheat farmers could both maintain their yields and improve soil health by growing annual wheat without tilling the soil year after year.
This could be one more encouragement to farmers to adopt a sustainable practice commonly called conservation tillage, no-till or minimum-till cultivation, impacting how we grow a grain that supplies about 20 percent of the calories and protein for people around the world.
A new study, by a team led by Mark Lundy, University of California Cooperative Extension specialist in UC Davis' Department of Plant Sciences, offers new insight for decades-long discussions around soil conservation, sustainable agriculture and climate-warming emissions related to growing our food. The study has been published in the journal Soil and Tillage Research. For the first time, researchers have shown that annual wheat that is not tilled each year is better for stashing carbon in the soil than perennial wheatgrass, while still yielding more crop in Central California.
Previous studies have looked at annual wheat that is tilled each year, annual wheat that is not tilled, and a cousin species, perennial intermediate wheatgrass (trademarked Kernza), which also is not tilled. But until now, no one has looked at all of the benefits and trade-offs together. Most importantly, “no one has ever controlled for tillage,” Lundy said. “And, no one has compared annual wheat to perennial intermediate wheatgrass over multiple years in a Mediterranean climate, which is what we have in California.”
This study also is unique because it delves into the deeper question of what is going on in the soil that drives the different results for carbon there. Soil carbon reflects various processes linked to plant activity and soil health. Measuring the different forms of soil carbon may also signal whether a farming system is accumulating carbon in the soil over time – a plus for reducing climate-warming gases in the atmosphere.
“Measuring soil carbon is complex and nuanced,” said Kalyn Taylor, the lead author on the paper. “We started this experiment because we wanted to know whether and how plant activity and tilling or not tilling would affect the carbon story belowground in California's climate.”
“When we started this study, we thought the crop being perennial or annual would drive the differences in carbon storage in the soil,” Lundy added. Specifically, they had expected perennial wheatgrass would lead to more carbon in the soil because of its deeper, better-established root system. “But that's not what we found,” he went on. “What we found was, it was the lack of tillage, plus the level of productivity of common annual wheat, that made the difference in soil carbon here in California.”
Soil carbon in annual vs. perennial grain
In 2017, Lundy, then-graduate-student Taylor, UC Davis Professor Emeritus Kate Scow and others on the team started measuring different forms of soil carbon in test plots at Russell Ranch, west of campus. Plots were planted with annual wheat that was tilled each spring, annual wheat that was not tilled and perennial intermediate wheatgrass (Kernza) that also was not tilled.
Each year, the researchers measured the carbon present in the soil, the amount of soil organisms (which have carbon in their bodies) and the amount of material the plants created.
At the end of three growing seasons, they found that land planted with no-till, common, annual wheat had the highest amount of soil organisms, measured as biomass, of the three treatments.
The researchers also found soil carbon is more likely to remain stable in the no-till, annual plots, compared to both tilled wheat and wheatgrass.
In addition, the no-till, annual wheat produced plant material more consistently than the perennial wheatgrass across the three years, which saw variation in rainfall.
“Overall, annual wheat grown without soil disturbance or tillage had both higher productivity and higher potential for storing carbon in the topsoil than perennial wheatgrass in our Mediterranean climate,” Lundy said.
Related research
“No-till annual wheat increases plant productivity, soil microbial biomass, and soil carbon stabilization relative to intermediate wheatgrass in a Mediterranean climate,” is online now and will be published in the January 2024 edition of Soil and Tillage Research.
The team also found that tilled annual wheat vs. Kernza stores total carbon at different depths in the soil profile and hosts distinct soil fungal communities, primarily in the root zone and topsoil: Taylor, K., Samaddar, S., Schmidt, R., Lundy, M. and Scow, K., 2023. Soil carbon storage and compositional responses of soil microbial communities under perennial grain IWG vs. annual wheat. Soil Biology and Biochemistry, p.109111.
Previous work comparing the perennial grain known as intermediate wheatgrass (trademarked Kernza) to annual wheat had not distinguished the extent to which soil health benefits are a function of the perennial nature of the crop. Read the story here.
This story was originally published on the UC Davis News site.
First-ever Queensland fruit fly quarantine restricts moving homegrown produce
QFF quarantine in LA, Ventura counties among seven fruit fly quarantines statewide
Residents in multiple Southern California and Northern California counties should not move homegrown fruits and vegetables from their properties to help contain several species of fruit fly that can destroy crops and impact the livelihoods of local farmers.
With sharing and gifting of food integral to the holiday season, the California Department of Food and Agriculture is reminding people to heed the seven active fruit fly quarantines aimed at controlling the Mediterranean fruit fly, Oriental fruit fly, Tau fly and Queensland fruit fly. The links below describe quarantine zone boundaries:
- Mediterranean fruit fly: Los Angeles County, Leimert Park Area
- Oriental fruit fly: San Bernardino and Riverside Counties, Redlands and Yucaipa Areas
- Oriental fruit fly: Sacramento County, Rancho Cordova Area
- Oriental fruit fly: Contra Costa County, Brentwood Area
- Oriental fruit fly: Santa Clara County, Santa Clara Area
- Tau fly: Los Angeles County – Stevenson Ranch, Valencia, Santa Clarita Areas
- Queensland fruit fly: Ventura and Los Angeles Counties, Thousand Oaks Area
People within these zones should consume or process (i.e., juice, freeze or cook) their homegrown fruits and vegetables at the place of origin and not move them off their property. Uneaten produce should be double-bagged in plastic bags and disposed of in the landfill bin – not compost or green waste.
Queensland fruit fly threatens California citrus, other crops
The Queensland fruit fly (Bactrocera tryoni) quarantine is the first of its kind in the U.S. Although QFF was first seen in California in 1985, the recent detection of two adult males triggered the unprecedented quarantine action by USDA's Animal and Plant Health Inspection Service and CDFA.
“This pest has earned a bad reputation for wreaking havoc on fruit production in Australia, where it is native,” said Hamutahl Cohen, University of California Cooperative Extension entomology advisor for Ventura County. “Adult flies lay their eggs in fruit, and the eggs hatch into larvae that then feed on the fruit, causing damage.”
And while females of other fruit fly species live for only two or three months, QFF females are unique in that they can live up to a year, according to Cohen.
“Once QFF populations take root, they're challenging to manage because females can each lay up to 100 eggs per day,” Cohen said.
In addition to being highly adaptable to a variety of environmental conditions, QFF has more than 170 host plants – including a wide range of California commodities such as citrus, grape, strawberry, fig, avocado, apricot, peach, cherry, nectarine, plum, pear, apple, tomato and sweet pepper.
The threat to citrus is especially concerning, as Southern California growers continue to grapple with the specter of spreading huanglongbing (HLB) disease, which kills citrus trees. Cohen said residents of citrus-growing regions can do their part to help their neighbors and local economy by respecting quarantine restrictions.
“Growers are already dealing with other invasive species like Asian citrus psyllid [vector of HLB pathogen], so we as homeowners need to prevent the spread of fruit flies to reduce the burden on them,” she explained.
While a spike this year in the detections of multiple fruit fly species was likely caused by a host of factors, Cohen speculates that increased post-pandemic travel is helping to move the flies. And with holiday travel in full swing, she said it's important to practice “Don't Pack a Pest” principles.
“Invasive species often hitchhike on fruits and vegetables brought into California by travelers – that's why we often first find invasive species in urban and suburban backyards, and not on farms,” Cohen said. “Travelers entering the U.S. can visit dontpackapest.com to learn about which products they can and cannot bring back with them.”
To report a suspected infestation of fruit fly larvae in homegrown produce, call the CDFA pest hotline at 1-800-491-1899. Growers with questions and concerns are urged to contact their local agricultural commissioner's office.
Winter season: A time for food safety systems re-evaluation and education for food hubs
The holiday meal season is often a busy time for food hubs – entities that handle the aggregation, distribution and/or marketing of source-identified regional food – as restaurants, retailers and consumers fill their tables and shelves with an abundance of fresh, local products. However, the subsequent winter months can provide a valuable time for reflection and re-evaluation of a food hub's systems and processes. In this spirit, it may be helpful to remind people working at food hubs that University of California Sustainable Agriculture Research and Education Program (UC SAREP) offers a suite of food-safety resources – in English and in Spanish – on its website.
- A step-by-step guide for food hubs on how to pursue a third-party food safety audit with guidance on how to navigate buyers' questions.
- Two sample food-safety plans intended as a starting point to be adapted to a food hub's specific operations and practices.
- Example standard operating procedure, or SOP, documents related to 11 common tasks carried out by food hubs.
“We hope these resources can play a role in helping food hubs to adopt best practices and control risks related to food safety,” says Gwenael Engelskirchen, sustainable food and farming coordinator with UC SAREP, who led the development of these educational tools.
According to the Centers for Disease Control and Prevention, approximately, 1 in 6 Americans (or 48 million people) gets sick and 3,000 die of foodborne diseases annually. In 2011, to help prevent the occurrence of foodborne illness, the federal government enacted the Food Safety Modernization Act (FSMA), designed to outline actions to be taken at various points along the supply chain for both human and animal food.
UC SAREP's Food Safety Resources for Food Hubs are intended to help food hubs navigate these food-safety regulations and accompanying best practices. Resources are also available in Spanish at Recursos de seguridad alimentaria para los centros de distribución de alimentos.
Food safety certification guide
Some buyers verify a supplier's food safety program by requiring an audit performed by a third-party certification body or auditing company. This Guide to Food Safety Certification offers key considerations before deciding to pursue a food safety audit and helps users navigate the food safety certification process.
Food safety plan
Food hubs that meet the criteria for full compliance with FSMA's Preventive Controls for Human Food Rule are required to have a food-safety plan in place. And for all food hubs, having a shared document describing the facility's operations and how potential risks of food contamination are managed is a good idea. Two sample food safety plans, inspired by the operations of food hubs in California, provide a starting point and can be adapted to a hub's own operations.
Standard operating procedures
Standard operating procedures provide detailed step-by-step instructions for how to carry out operational tasks within a food facility. The standard operating procedure samples cover common topics such as handwashing, facility cleaning and more, and are intended to be adapted to a food hub's specific operations and practices.
Jacob Weiss from Spork Food Hub in Davis said, “the templates were a great starting place for us to build the framework of our food safety plan. It helped us figure out what we needed to (and didn't) need to include. I think the SOPs are also really useful because they are broad enough to get you started but flexible enough to add the specific practices of your business or hub.”
For additional information, visit UC SAREP's webpages on Food Safety Resources for Food Hubs or Recursos de seguridad alimentaria para los centros de distribución de alimentos.
These resources and tools were developed in collaboration with various project partners, including Department of Food Science and Technology at UC Davis, Department of Population Health and Reproduction at UC Davis School of Veterinary Medicine, Center for Precision Medicine and Data Science at UC Davis Health, and Community Alliance with Family Farmers.
