Posts Tagged: Agriculture
Visual ID guide from UC aids in managing new almond pest
Nut orchard hygiene key to control carpophilus beetle, say UCCE, UC Integrated Pest Management experts
Since the first reports of a new almond pest – the carpophilus beetle (Carpophilus truncatus) – came in during fall 2023, it has become clear that the beetle is widely dispersed across the San Joaquin Valley.
“My lab has identified infestations from every county in the San Joaquin Valley; we have found infestations in both almonds and pistachios, and we will likely find infestations in walnuts this fall,” said Houston Wilson, a University of California Cooperative Extension entomology specialist at UC Riverside. The California Department of Food and Agriculture has confirmed the beetle's presence in Stanislaus, Merced, Madera and Kings counties.
Historically a major threat to almond production in Australia, the beetle – as larvae and adults – feeds directly on the nut kernel. In California, some almond growers have lost 10 to 15% of their yield – a “significant economic loss,” according to Jhalendra Rijal, University of California integrated pest management (IPM) advisor for the region. Given the prominence of almonds as a commodity, even a 1% overall reduction statewide represents an approximately $70 million loss.
“This year there has been a lot more reports from PCAs [pest control advisers]; they're sending me the pictures of the damage and beetles,” said Rijal, noting that the increase is likely due to greater awareness of the pest.
To help almond growers identify the carpophilus beetle and develop management plans, Rijal, Wilson and their IPM colleagues have put together a visual ID guide for the beetle and the damage it causes, as well as telltale signs of navel orangeworm (Amyelois transitella) and ant damage. In particular, the experts would like PCAs and growers to differentiate between the carpophilus beetle and navel orangeworm, another key pest in almonds.
“Even though their way of causing damage looks more or less similar, we're dealing with two different types of insects,” Rijal explained. “One is a Lepidoptera moth [navel orangeworm], and the other one is a beetle – many of the management practices and biological controls would be different for these two different things.”
To control carpophilus beetle, ‘sanitize, sanitize, sanitize'
One crucial cultural practice for managing both pests, however, is destroying the remnant “mummy” nuts – the nuts that remain in the orchard postharvest. They serve as overwintering habitat for the carpophilus beetle, as well as its sustenance for the next generation of beetles in spring.
“The best way to manage this pest is to do the orchard hygiene – continuing the winter sanitation, destroying the nuts that are on the ground and on the tree and on the berms,” Rijal said.
Based on observations in Australia and locally, carpophilus beetles tend to rely more on mummies on the ground, whereas navel orangeworm generally favors mummies in the tree canopy. Correctly identifying the pest – with help from the new ID guide – enables growers to better target and prioritize their management efforts, Rijal said.
“What we are strongly emphasizing is that growers need to sanitize, sanitize, sanitize to control both pests,” Wilson added.
Correct identification of the pest would also prevent unnecessary application of insecticides, as those used for controlling Lepidoptera such as navel orangeworm would be largely ineffective on the beetle.
Indeed, another insight shared by Australian experts is that the carpophilus beetle cannot be controlled just by insecticide.
“Insecticides are not very efficient, given the cryptic nature of these beetles; exposing these beetles to the insecticide is very hard,” said Rijal, noting that the beetle spends most of its life cycle protected inside the nut.
Reporting carpophilus beetle infestation helps researchers
This harvest season, Rijal advises almond growers to harvest as efficiently as possible, to minimize the number of mummies that need to be cleaned up. And because signs of damage (like damaged hulls and frass) are most obvious during harvest time, Rijal said growers should review the new guide, using the photos and other resources to help identify potential pests.
If the grower or PCA suspects a carpophilus beetle infestation, they should contact the UCCE farm advisor in their area.
Scientists are looking to expand their knowledge about this relatively new pest to California. In the coming weeks, for example, researchers are planning to survey for the carpophilus beetle in the Sacramento Valley.
“Technically it has not been found there, but we suspect that we'll find it this fall when we go looking for it,” Wilson said.
Researchers are also collecting samples from infested orchards to better understand the biology of the species, as well as how it progresses through and responds to seasonal and climactic changes. In addition, they are analyzing data from a trial study of an insecticide that might be used as a supplemental control measure.
“This is our first full season dealing with this insect, and there are still many things we need to understand,” Rijal said. “We are continuing our research efforts on all fronts.”
/h3>/h3>/h3>Could empty lots be growing food, economic opportunity?
UCCE scientists study feasibility of specialty crops for small urban growers
The vacant lots around your neighborhood could be growing fruits and vegetables and making local produce more accessible – while reducing energy needed to transport and distribute the food. Could turning those empty lots into small farms also become opportunities for economic development?
To answer this question, a team of researchers from University of California Cooperative Extension in San Diego County are investigating the economic feasibility of growing high-value specialty crops in urban settings like vacant lots. The project – led by Eric Middleton, UCCE integrated pest management advisor for San Diego, Orange and Los Angeles counties – is currently in progress at The Flower Fields in Carlsbad, a seasonal attraction for locals and tourists.
Tucked away in the back of the field is the Small-Scale Urban Ag Demonstration Site where Middleton and his team established a small farm on approximately 17,000 square feet, starting fall 2023. Funded by the U.S. Department of Agriculture National Institute of Food and Agriculture, the farm is designed to evaluate containerized production both outdoors and under high tunnels.
Growers don't necessarily need land, just space
High tunnels, also referred to as hoop houses, are semi-permanent structures that act similarly to greenhouses in providing a controlled environment. For the experiment, Middleton will compare cost, effort and durability of two types of high tunnels: one made of steel and the other out of PVC pipes.
“We want to give interested growers information on as many options as we can,” said Middleton, who explained that the project is motivated by the challenges of urban settings, including limited space and lack of arable land.
In the trial, they are growing turmeric, ginger and blueberries. The high-value crops were selected because of their potential to earn a profit. Data evaluating plant variety, soil mix, fertilizer, growth performance, yield and pest and disease pressures will be collected and reported when the project concludes in 2026.
As the crops develop in containers – blueberries in pots and turmeric and ginger in grow bags – Middleton pointed out the mobility aspect of the study, noting that growers don't necessarily need land, just space.
Whether it's a backyard or a rooftop, containerized production means easier transport, especially since vacant land doesn't always remain vacant forever and urban lots may often need soil remediation. Growing in containers solves the anticipated problem of having to relocate.
Where to set up shop in San Diego County
Jan Gonzales, project coordinator and community education supervisor for UCCE San Diego County, is leading the effort to identify available urban land in San Diego County as well as the policies and procedures for growers to access these spaces.
Gonzales is collaborating with community members who are working on similar projects to identify space for prospective growers.
“This has been done before for different objectives and for specific areas in the region, but the information was either project-specific and not publicly available, or not easy to find,” Gonzales said.
Having spoken with people associated with previous or ongoing agricultural land mapping projects, Gonzales has agreed to coordinate and facilitate an advisory work group to discuss areas of potential collaboration and develop project efficiencies. She anticipates holding the first group meeting before the end of the summer.
A production guide to help community members re-create the project
The ideal audience for a study like this is anyone who wants to grow specialty crops, according to Lindsey Pedroncelli, interim director of UC South Coast Research and Extension Center in Irvine, who worked on the project alongside Middleton when she was a staff research associate with UCCE San Diego.
“If you're a new grower or a grower who wants to diversify your crop production, what we're learning here can be applied to you,” said Pedroncelli.
Pedroncelli has been instrumental in bringing the experiment to life and documenting its step-by-step workflow thus far. The production guide, which is being created as the study unfolds, will include instructions detailing how to replicate the experiment from the ground up. Currently, it contains information on how to design your farm, the materials to buy, building structures, irrigation setup and crop management.
The most intriguing open question, whether the operation is profitable, is the driving force behind the production guide and will certainly be addressed, Pedroncelli said.
Book a tour and visit the farm
When visiting the farm, you'll encounter three varieties of blueberries: Star, Snowchaser and Misty. Snowchaser has been a top producer since it was planted in January, but the variety is known to be an early season producer.
Using only one variety of each, the turmeric and ginger were planted in late March-early April. With some unanticipated cold weather in San Diego County, both crops struggled when transitioning out of dormancy, leading to very slow progress, which the team is still navigating today.
Visually, Middleton and his team have noticed differences between the crops growing under the high tunnels versus those grown outdoors, although the data has not been analyzed to confirm or explain notable differences.
Attempting to demonstrate how to profitably grow high-value crops in urban settings using limited space and resources, Pedroncelli said she hopes this study will also encourage people to grow culturally significant crops for their communities.
To tour the Small-Scale Urban Ag Demonstration Site at The Flower Fields in Carlsbad, email Eric Middleton at egmiddleton@ucanr.edu with "Urban Agriculture Demonstration Site Tour" in the subject line.
To learn more about the project and its progress, visit https://ucanr.edu/sites/socalIPM/Small_Scale_Urban_Agriculture_Project_/.
/h4>Paper highlights how climate change challenges, transforms agriculture
As the climate continues to change, the risks to farming are only going to increase.
That's the key takeaway from a recent paper published by a team that included UC Merced and UC Agriculture and Natural Resources researchers. The paper dives into what those challenges are, how farmers are working to address them and what should come next.
"Climate Smart Agriculture: Assessing Needs and Perceptions of California's Farmers" was first authored by Samuel Ikendi, academic coordinator, with Tapan Pathak, UC Cooperative Extension climate adaptation in agriculture specialist, as a corresponding author. Both are based at UC Merced. Pathak is also a project director of National Institute of Food and Agriculture-funded project "Multifaceted Pathways to Climate-Smart Agriculture through Participator Program Development and Delivery," which supported this study. The study appeared in the open access journal Frontiers in Sustainable Food Systems.
The needs assessment was designed to understand farmers' perceptions and experiences with climate change exposures; the risk management practices they currently use; and what tools and resources would assist them in making strategic decisions.
Of the farmers surveyed, roughly two-thirds agree climate change is occurring and requires action. Even more said they are interested in learning more about the impacts of climate change on the agricultural industry. Most respondents said they experience greater climate change impacts on their farms today compared with 10 years ago.
Farmers were very concerned with water-related issues, with those in the San Joaquin Valley, Central Coast and Inland Empire areas particularly worried about a reduction in the availability of groundwater. Increased drought severity was a very significant concern among farmers in the Inland Empire, Central Coast and Southern regions. Farmers in the North Coast and Southern regions were concerned about increased damage to crops due to wildfire.
Closely related were temperature-related issues, including crop damage due to extreme heat.
Those who farm vegetables were more concerned about water availability for irrigation, while fruit farmers were more concerned about increased crop/water stress and increased crop damage due to extreme heat.
Many respondents said they are implementing climate adaptation practices including managing water resources, maintaining soil health and making more use of renewable energy sources. They are seeking insurance and government help to pay for these adaptations and increase their agricultural resilience, the researchers wrote.
The farmers expressed interest in learning more about measures they might take to mitigate climate change. But they cited significant barriers to this work, including government regulations, high implementation cost, labor access/cost, access to water and the availability of money to pay for it.
"Climate change is significantly altering California's highly diverse agricultural landscape, posing challenges such as increased water stress, heat stress, and shifting growing seasons," Pathak said. "Climate-smart agriculture practices can alleviate some of those stresses."
But, he said, research and UC Cooperative Extension efforts only have value if they lead to enhanced climate-informed decision-making at the local level.
"Assessing their level of knowledge, perception and needs will help in tailoring research and extension activities that are most relevant to farmers on the ground," Pathak said. "Results from this study could also provide important policy insights on financial incentives and technical assistance."
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Almond crop yields threatened by disease new to California
Detection of fungus causing red leaf blotch spurs call for grower vigilance
Symptoms of red leaf blotch (RLB), a plant disease caused by the fungus Polystigma amygdalinum, have been observed for the first time in California across the Northern San Joaquin Valley.
Molecular DNA testing by the laboratory of Florent Trouillas, University of California Cooperative Extension fruit and nut crop pathology specialist, has detected P. amygdalinum. Pest identification was confirmed by the California Department of Food and Agriculture and U.S. Department of Agriculture.
The disease, named for the characteristic orange-to-dark red blotches that appear on infected leaves, is typically nonlethal for trees but has been a long-standing problem for almond-growing regions across the Mediterranean. Causing trees to lose their leaves prematurely, the fungal pathogen can significantly diminish crop yields in the current year and the next.
“It is one of the most severe diseases of almonds for Spain and the Middle East,” said Trouillas, an associate professor in the UC Davis Department of Plant Pathology. He recently co-authored an explanatory article on the UCCE San Joaquin Valley Trees and Vines blog.
With symptomatic trees seen in multiple orchards across Madera, Merced, San Joaquin and Stanislaus counties, Trouillas said RLB is already “somewhat widespread.”
“From the first observations so far, it seems like it affects some of the most-planted cultivars, like Nonpareil and Monterey,” he added. “We've observed it in a diversity of cultivars already.”
UC Cooperative Extension specialist urges taking preventive measures
According to Trouillas, RLB caused by P. amygdalinum is “highly specific” to almond trees, and generally only affects their leaves. Infection typically happens at petal fall, when small leaflets are first emerging and most susceptible to disease. After the pathogen's latent period of about 35 to 40 days, the first symptoms appear – small, pale-yellow spots on both sides of the leaves.
Those blotches become yellow-orange and then reddish-brown in the advanced stages of the disease during June and July. Now, with RLB symptoms becoming more prominent, Trouillas and UC Cooperative Extension advisors across the Central Valley have seen an uptick in calls.
“PCAs [pest control advisers] have been confused because they've never seen anything like this,” said Trouillas, noting that the yellow-orange-red blotches are symptoms unique to RLB and cannot be confused with other known almond diseases.
Applying fungicides after RLB symptoms appear is ineffective, Trouillas said. The best thing growers can do at this point is to report symptomatic trees to researchers so they can track the prevalence and distribution of the disease.
Growers who see signs of this new disease in their orchard should contact their local UC Cooperative Extension farm advisor.
Preventive measures are the best way to manage RLB, Trouillas said. He urges concerned growers to think ahead to next winter/spring and plan for fungicide applications at petal fall and – if rains persist – also at two weeks and five weeks after petal fall. Fortunately, those are the same three key timings for managing other diseases, like shot hole and almond anthracnose.
“Because RLB is something that is introduced and potentially aggressive, it will be important for growers to keep that in mind next year and be on schedule for next year's spraying program,” Trouillas said.
Additional information on RLB can be found at https://www.sjvtandv.com/blog/first-detection-of-red-leaf-blotch-a-new-disease-of-almond-in-california.
/h3>/h3>Diagnosing herbicide problems takes detective work
Field day offers examples, tips for solving the mystery
A grower applies an herbicide to his tomato plants, or thinks a neighbor's treatment is drifting over her almond trees. A short time later, the leaves start to bleach or shrivel. Was it the herbicide? Or maybe water stress? Soil nutrients? Perhaps an insect?
Figuring out the causes of crop problems takes detective work, and like solving any mystery, it starts with knowing the signs, gathering evidence and asking questions.
The Diagnosing Herbicide Symptoms field day at UC Davis was an opportunity to see, up close, the shriveled cotton, scorched corn and dying sunflowers that can result when herbicides are applied incorrectly. Using the right herbicide – in the right proportion, at the right time and in the right field – can make the difference between a thriving crop and a financial loss.
A top take-away to avoid problems: “Don't do stuff at night!” laughed Becky Wheeler-Dykes, a UC Cooperative Extension farm advisor attending the June 26 event to better serve growers in Glenn, Tehama and Colusa counties. “The packages look the same. People grab the wrong jug.” And then, disaster.
Instructors were Brad Hanson, professor of Cooperative Extension; and Kassim Al-Khatib, the Melvin D. Androus endowed professor for weed science; both in the Department of Plant Sciences. They were joined by John Roncoroni, a Cooperative Extension emeritus farm advisor rooted in the department's weed science program. Attendees were a mixture of people from agriculture, industry, government officials, university researchers and Cooperative Extension advisors. The event was hosted by the Weed Research and Information Center, based in the Department of Plant Sciences.
Out in a field west of campus, visitors could see the progression of damage, from control plots with green and healthy crops to plants that looked sadder as herbicide concentrations increased. Visitors could see the patterns of damage for common foliar chemicals such as glyphosate, paraquat, and 2,4-D, as well as soil-applied herbicides from several chemical classes.
“There's a lot of detective work,” said Stephen Chang, a master's student in Hanson's lab aiming for a career in Cooperative Extension. “For example, the company that makes the herbicide says there shouldn't be a problem, but the grower says, there is a problem. This course helps with developing the skills to figure out what happened.”
It might not be the herbicide at all
Detective work and problem-solving frame the approach, Hanson explained. The cause of crop damage can be simple or complex. Like a good mystery, what appears to be a clue can turn out to be a red herring. Professionals need to draw on their inner Sherlock Holmes to observe and document symptoms, look for patterns in the plants and in the field, ask questions, gather information about the larger environment and collect samples.
An herbicidal Agatha Christie would then suggest: What if it's not herbicide damage at all? Participants learned to consider the possibility of insects, pathogens and viruses, as well as problems with water, nutrients, soil condition and even root damage from cultivation practices.
Hanson recalled puzzling over symptoms he found in an orchard. The culprit? “A leaking natural gas line,” he said.
More resources for herbicide issues
Participants also heard from Molly Mathews, deputy agriculture commissioner from Yolo County, on how a field investigation is conducted. Lawyer Robert Davies, of Donahue Davies LLP in Folsom, outlined the basics of what happens when there are lawsuits related to crop damage from herbicide drift.
The Diagnosing Herbicide Symptoms field day is part of a larger program of education and outreach offered through the Weed RIC, said director Julia Stover-Blackburn. It was the first time the event has been offered since the COVID-19 pandemic, she added.
- For more information about field days and resources, visit the Weed RIC webpage.
- For a thorough discussion of herbicide symptoms, visit this page overseen by Al-Khatib and sponsored by University of California Agriculture and Natural Resources.
- This online course follows an earlier version of the Diagnosing Herbicide Symptoms field program.
This story was originally published on the UC Davis Department of Plant Sciences website.
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