California Ag Network

Category: Pest/Disease Management

  • $650,000 Grant to Study Wild Wheat to Help Prevent Diseases

    The 2Blades Foundation and collaborators at the University of Minnesota, Kansas State University, and the John Innes Center will study wild emmer wheat to discover genes that can help farmers combat devastating wheat rust diseases which are estimated to cost farmers and consumers nearly $3 billion each year.

    The United States Department of Agriculture’s National Institute of Food and Agriculture has awarded a grant through their Agriculture and Food Research Initiative (AFRI) for the study of emmer wheat — one of the very first cereals to be cultivated in agriculture — to identify genes that could help make wheat resistant to “rust” diseases.  Wheat rusts have destroyed crops since Roman times, including multiple epidemics in the US in the past century.

    The current project builds on 2Blades’ 12-year effort to source resistance genes from wheat and its domesticated and wild relatives, and to deploy them in finished wheat varieties. It brings together leading scientists in wheat and wheat rusts with key resources.

    The project team includes:  Jesse Poland, a wheat geneticist at Kansas State University’s Wheat Genetics Resource Center, which maintains extensive collections of wild wheat relatives including wild emmer wheat; Brian Steffenson, a plant pathologist at the University of Minnesota, with extensive expertise in cereal rusts and specialized facilities for conducting resistance assays; and Brande Wulff, from the John Innes Centre in the United Kingdom, who has developed the methodology to quickly identify resistance genes through association genetics.

    Wheat provides roughly 20 percent of calories and protein for human nutrition worldwide and is the third largest crop grown in the United States. It is attacked by a number of diseases, among the most damaging being stripe rust (Puccinia striiformis), stem rust (P. graminis), and leaf rust (P. triticina).

    The best and most environmentally sound way to defend against these diseases is through the deployment of resistance genes in wheat varieties. The use of genetic resistance is particularly important in developing countries where fungicides used to combat rust disease may be expensive or unavailable.

    The world wheat harvest is threatened by the recent emergence of new virulent forms of the fungal pathogen Puccinia graminis, which can cause pandemic disease with the rapid and complete destruction of infected crops.

    “In the face of this threat to world food security we are working with our partners in the United States, England, Australia and Japan to develop new wheat lines which are completely and securely disease resistant, and to ensure that these lines are available to farmers everywhere, and freely available to farmers throughout the developing world,” said 2Blades Chairman Roger Freedman.

    Read More at 2Blades.org

  • BASF Files Motion to Intervene in Ninth Circuit Case that Vacated Dicamba Registrations

    BASF has filed an emergency motion to intervene following the decision by the United States Court of Appeals for the Ninth Circuit to vacate the federal registrations of three dicamba-based herbicides, including BASF’s Engenia® herbicide. The Court’s June 3, 2020 decision brought BASF’s product into the case for the first time. BASF has now made the request to intervene after careful consideration of the sudden and severe financial impact vacating the registration has had on farmers during this critical application time, when farmers now have less than a month to protect millions of acres under threat from resistant weeds. The Ninth Circuit’s decision has caused immediate chaos among the agricultural community and threatens the livelihood of countless U.S. farmers. Seeking to make matters worse, the challengers have now asked the Ninth Circuit to undo the EPA’s order which implemented the panel’s decision and addressed the uncertainty it caused. BASF must act to protect its interests and those of its customers.

    “Taking this action during the height of the application season gives no regard to the significant investments farmers have made in their businesses and leaves them without viable options for the growing season,” said Paul Rea, Senior Vice President, BASF Agricultural Solutions North America. “Farming is difficult even in the best of times and remains challenging. Making this decision now, when weed resistance continues to threaten farming operations, is disastrous for our customers. Farmers have counted on applications of dicamba-based products to control troublesome weeds for decades, and they continue to need these tools now and in the future.”

    Since its original registration with the EPA in 2016, on-target applications of Engenia herbicide have helped farmers produce clean fields and robust yields of dicamba-tolerant soybeans and cotton. And because of BASF’s commitment to stewardship, the company provides customers with a range of practices, equipment, and trainings to make sure they have the tools to get the most out of BASF products, while protecting the environment.

    “I have been using Engenia for three years, and it is a critical part of my operation to reduce the threat of resistant weeds and ensure a successful yield each season,” said Brad Kallenbach, a soybean farmer from Jamestown, North Dakota. “My livelihood depends on tools like Engenia to tackle these challenges, and those of us that use it have dedicated a tremendous amount of time to ensure that we are doing it responsibly. The Court’s decision to vacate the Engenia registration leaves me with no good options for this year. It’s a steep cost that no grower under these circumstances was ready to bear.”

    The EPA’s approval process for crop protection products is science-based and data-driven. BASF invests in and uses the best science and testing protocols to develop next-generation innovations like Engenia herbicide. BASF scientists have over 50 years of experience in developing and improving dicamba for effective and safe applications.

    “Engenia and other dicamba-based herbicides are critical in ensuring the long-term sustainability of agriculture and crop protection products,” continued Rea. “Not only do they play a role in protecting crops, but also in ensuring an abundant, safe and affordable food supply. Continued innovation in crop protection and weed management must continue and be supported to sustain this industry.”

    BASF remains committed to meeting the needs of its customers and will continue to work on new dicamba-based innovations to assist farmers with weed control. In addition, BASF will also continue to pursue EPA re-registration of Engenia for the coming seasons.

    Engenia herbicide is a U.S. EPA Restricted Use Pesticide.

     Always read and follow label directions.

  • Three Ways to Prevent Almond Hull Rot

    As almond growers in California prepare for hull split, almond hull rot is often a problem on their minds during this time. As UC Cooperative Extension Orchard Systems Farm Advisor Franz Niederholzer says, prevention is key.  Watch this brief interview with Franz as he shares three tips on avoiding this costly issue in the orchard, and read more about it in Pacific Nut Producer Magazine. Don’t currently receive the magazine? Subscribe for free at: https://malcolmmedia.com/pacific-nut-producer-magazine-subscriptions/

  • Stinknet is Spreading in Southern California

    Stinknet (Oncosiphon piluliferum, aka globe chamomile) is a winter annual that is spreading across Southern California and poses threats to wildlands, rangelands and agricultural areas. Stinknet was first found in western Riverside County in the early 1980’s. It slowly spread to surrounding areas and by the late 1990’s it was found in over a half dozen locations in Riverside and San Diego Counties. By this time, it had also spread to Phoenix. While stinknet has not been one of the fastest weeds to spread across the state (stinkwort, Dittrichia graveolens, is definitely a top contender for that spot, see here) it is now currently found in every county in Southern California (except Imperial, yet) with the largest infestations in Riverside and San Diego Counties. Stinknet continues to spread north across Los Angeles, the central valley and coast, and east across Arizona, it was also recently found in Las Vegas.  

    Identification

    Stinknet is easiest to identify when in flower. At flowering, it grows from several inches to 3 feet tall.

    Stinknet in full flower (Image credit: Chris McDonald)
    A closeup of stinknet flowers (Image Credit: Chris McDonald)

    Stinknet is closely related to the pineapple weeds (Matricaria spp., see here) and brass buttons (Cotula spp. see here and here), and resembles those more common weeds. The main difference is the flower of stinknet is very round, like a globe, (see above) while the flowers of pineapple weed and brass buttons tend to be slightly conical to half a sphere.

    Brass buttons (Cotula coronopifilia Image credit: Carol Witham)

    Pineapple weed and brass buttons also tend to grow more along the ground, and stinknet grows upright. Another diagnostic feature is that stinknet stinks. All plant parts have an unpleasant turpentine, pine or tar-like smell, and even very small plants have this smell. You can even smell the odor of a large field of stinknet when you are near a very large infestation.

    Successful Control Options

    Stinknet can be controlled with several herbicides that can be used in wildlands. Milestone (aminopyralid), Capstone (aminopyralid and triclopyr) and glyphosate are all highly effective at controlling stinknet, but only before the plants have flowered. Often if herbicides are applied after flowering, stinknet can finish flowering before the herbicides have killed the plant. Milestone and Capstone also provide season-long control of stinknet with suppression lasting up to and in some cases beyond 12 months. Several researchers, including myself, are working on other control measures and understanding its biology to better help managers control stinknet. Those projects should wrap up in the next year or two.

    What doesn’t work well at controlling stinknet? 

    Telar XP (chlorsulfuron) was not effective at controlling stinknet in Southern California. Transline (clopyralid) was inconsistent at controlling stinknet. Transline had shown promise of effective control in relatively dry years, but in other more wet years the treated plants were able to grow out of the treatment. Mechanical removal (mowing or string trimmers) has shown to be of limited effectiveness, mostly because the cut plants resprout and flower closer to the ground. Multiple cuttings close to the ground alleviate this problem and can provide good control, but a simple single cutting is not very effective. Stinkent can grow in dense patches so hand pulling will only work on a very small scale, and multiple sessions are needed. Stinknet is not palatable to livestock, so grazing will not be an effective management strategy and can make the problem worse.

    Threats to California Agriculture

    In Western Australia, stinknet is a problem weed in small grain crops. In both South Africa (the home range of stinknet) and Austrailia stinknet is a problem weed in rangelands too. This is because stinknet is unpalatable to many livestock. While stinknet is not currently known to be toxic, there are reports it can taint the meat and milk from those animals. If the patterns in Australia and South Africa hold in the US (and so far in a few observed cases it appears to be similar) and if stinknet continues to spread into rangelands and agricultural areas in California, then it will cause problems.

    EDRR

    Right now, the best way to keep stinknet from spreading locally in California is to identify early infestations and rapidly respond to those initial infestations. This strategy is called early detection and rapid response (EDRR). Fortunately, the largest stinknet populations are found in only a few locations in Riverside, San Bernardino and San Diego Counties. However, numerous small populations occur across Southern California. I have also noticed that very few stinknet patches decline in size, once stinknet colonizes a site it tends to expand, or even hold its ground during a drought. The areas with the earliest known stinknet populations, in both California and Arizona, now have large, very high-density patches. Those patches can be over a dozen and up to hundreds of acres in extent. Stinknet appears to be a strong competitor especially in disturbed areas, but also in undisturbed wildlands too, and can quickly become the dominant plant. It does this by creating numerous small patches and as those patches grow, they form large blankets carpeting acres or long strips along roads and trails. Stopping those small stinknet patches can prevent them from turning into large infestations.

    More information on stinknet will be available as our research progresses and we learn more about its biology, spread and controlling it. — By Chris McDonald, UCANR

  • New Recommendations for Laurel Wilt Disease

    By Ben Faber, UC Cooperative Extension — Laurel Wilt Disease of Avocado and the relatives of avocado in the Laurel Family has devastated the the forests along the east coast from North Carolina down to Florida and along the Caribbean into Texas.  It has caused significant losses to wildlands and to the Florida avocado industry.

    Ambrosia Beetle

    The extent of the native tree loss is shocking and there is very little that can be done to correct the problem, other than to curb the spread of contaminated wood that is spread by humans,  There has been some success in the avocado orchards. While there is no “silver bullet”, there is some progress, e.g. pruning to increase light levels to suppress Ambrosia Beetle activity.  In addition, research has continued for:

    • Vaccinations to protect avocado trees from the LW pathogen
    • Developing a faster LW diagnostic tool
    • Screening scions and rootstocks for tolerance/resistance
    • AB control tactics and suppression
    • Molecular understanding of the pathogen
    • Economics and the LW epidemic

    Read the latest results in these two recent publications:

    Recommendations for the Detection and Mitigation of Laurel Wilt Disease in Avocado and Related Tree Species in the Home Landscape

    Recommendations for Control and Mitigation of Laurel Wilt and Ambrosia Beetle Vectors in Commercial Avocado Groves in Florida1

    Dead avocado trees from Laurel Wilt in Florida

  • Bringing the Next Generation of Avocados to Market

    UC Riverside has entered into a $2.25 million partnership with Spain-based Eurosemillas S.A., a global leader in the commercialization of agriculture innovations, to help the university bring to market the most promising and advanced avocado scions and rootstocks in its collection.

    If successful, these varieties would meet diverse regional growing requirements, exhibit better post-harvest characteristics, increase yields, provide resistance against disease, and expand consumer market diversity.

    “Eurosemillas has successfully commercialized citrus varieties developed at UC Riverside in the past. They have the global network and expertise to do the same with the next generation of avocados,” said Brian Suh, director of technology commercialization in the Office of Technology Partnerships at UC Riverside, who worked with a team on this initiative for the past four years.

    Eurosemillas will obtain access to a small subset of the overall university avocado variety and rootstock collection for evaluation and testing on various continents to see if they perform as well as they do in California. At the same time, they will forge partnerships for commercialization that could lead to global market penetration of some of these selections.

    Niwala Abeysekara uses a leaf sensor on avocado plants in the Manosalva lab at UC Riverside. (UCR/Stan Lim)

    “After 31 years of working with UC on many other crops, we are delighted to partner with UCR again in a new product like avocado,” said Javier Cano Pecci, Chief Executive and Development Officer of Eurosemillas. “The avocado market is growing and is currently dominated by the Hass variety. This is a great opportunity for growers, marketers, retailers, and consumers to have options and diversify to include better avocado varieties and rootstocks adapted to their regions.”

    UC Riverside’s 70-year old avocado breeding programs house one of the most elite germplasm collections of scion and rootstock breeding material in the world. The University of California has partnered with California avocado growers since the inception of the industry a century ago and has had several plant breeders developing new varieties and rootstocks for the industry.

    Bob Bergh headed the variety improvement program for nearly 40 years, which released among other varieties, the ‘Lamb Hass’ and ‘GEM.’  This program is under the leadership of Mary Lu Arpaia, an extension horticulturist. The goal of the variety breeding program is to develop trees with high eating and market quality while increasing yield efficiency.

    Arpaia said for the California industry to remain viable, growers must have new varieties that yield more than Hass, are more tolerant to environmental stress, and can be produced reliably under high-density planting systems.

    “I am delighted by this partnership with Eurosemillas since it will help UC take this vision for the future toward reality,” Arpaia said.

    Mary Lu Arpaia, UC Riverside Extension Horticulturist

    The variety improvement program has four selections being readied for release that can augment the ‘Hass’ variety in terms of seasonality and have potential for expanded environmental adaptation within California.

    The rootstock breeding program was started in the 1940s by George Zentmyer and is currently directed by Patricia Manosalva, an assistant professor of plant pathology at UCR. The UCR Rootstock Breeding Program is one of the few well-recognized rootstock breeding programs worldwide and has been historically funded by the California industry through the California Avocado Commission. The main goal of the rootstock program is to develop and release the next generation of rootstocks that meet the most pressing needs of growers using traditional breeding complemented with genomic-assisted breeding approaches.

    The program is selecting rootstocks that can resist Phytophthora root rot, the most common avocado disease worldwide, as well as salinity, drought, and heat, all of which are expected to become worse as the climate warms. In collaboration with the California Avocado Commission, five UC Riverside advanced rootstocks exhibiting resistance to these major challenges are being evaluated by growers throughout California.

    “This partnership with Eurosemillas will allow us to test our five advanced rootstocks in combination with ‘Hass’ and local scions in other countries to determine their potential outside California,” Manosalva said.

    Peggy Mauk, director of agricultural operations and cooperative extension horticulture specialist, has been active in avocado research and extension for more than two decades. Over the past 25 years, avocado production in California and worldwide has been challenged by declining water quality. Avocado is the most salinity sensitive tree crop and ‘Hass’ is very susceptible to damage caused by salts. She initiated a program to find rootstocks tolerant to saline water.

    “Our UCR team in partnership with Eurosemillas is focused on finding rootstock/scion combinations that increase salinity tolerance,” Mauk said.

    Over the last 30 years, the avocado market has increased 2.5-fold and per capita consumption has quadrupled, generating interest in avocado production in many other countries, Manosalva said. But diseases, climate change, and the worldwide market’s dependence on the Hass variety threaten this burgeoning market.

    “The funding from Eurosemillas will allow UC Riverside to maintain the plant material and support and complement the current California Avocado Commission funding of the avocado scion and rootstock breeding programs, respectively, which have significant value given their uniqueness,” said Kathryn Uhrich, dean of UC Riverside’s College of Natural and Agricultural Sciences. — By Holly Ober, UC Riverside

    For more information on this avocado program contact Joyce Patrona: joyce.patrona@ucr.edu

  • Houston Wilson Named Presidential Director for the Clif Bar Endowed Organic Agriculture Institute

    Houston Wilson has been named the Presidential Director for the University of California’s Organic Agriculture Institute, which was established in January 2020 with a $500,000 endowment by Clif Bar and a matching $500,000 endowment from UC President Janet Napolitano.

    Wilson, a UC Riverside agricultural entomologist based at the Kearney Agricultural Research and Extension Center, joined UC ANR as assistant Cooperative Extension specialist in 2017. He will launch the institute and chart a path for future growth while also focusing on immediate priorities such as a survey of organic production in California, multiple outreach and training opportunities for growers, publication of organic production guidelines, and developing research programs. Wilson’s long-term goal is to continue to grow the endowment and position the organization to successfully support the state’s growing organic farming economy.

    “Organic growers in California face an array of interconnected agronomic, economic and regulatory challenges,” said Wilson. “Tackling these issues simultaneously requires a multidisciplinary approach to develop solutions that work in all scales of production. The economic opportunities are there, and we want to help position California growers to reap these benefits, and in doing so increase the supply of affordable organic food for consumers.”

    Since 2007, Wilson has conducted research and extension in orchard and vineyard systems with a focus on integrated pest management strategies, many of which are readily applicable to organic agriculture. Key studies have included evaluating the use of mating disruption to control navel orangeworm in fig production, cover crops to increase biological control of vineyard leafhoppers, pheromone lures to improve monitoring of leaffooted bug in almonds, and more.

    “We are excited about Houston’s vision for establishing and growing California’s first organic institute,” said Glenda Humiston, UC vice president for agriculture and natural resources (UC ANR). “Continued research advancements will be critical to the future of organic farming in our state as well as the health of our environment.”

    “Clif Bar is thrilled to see Houston’s appointment. We’ve heard from orchardists in our supply chain who have worked with him in the past and are excited that he’ll have more resources to help serve the needs of organic producers,” said Matthew Dillon, senior director of agriculture for Clif Bar. “We look forward to working with Houston, UC ANR, and the organic agriculture community to continue to improve the sustainability and economic resiliency of California farmers.”

    Wilson earned his doctoral degree in environmental science, policy and management and also holds a bachelor’s degree in international area studies, both from UC Berkeley.

    About UC ANR

    UC Agriculture and Natural Resources brings the power of UC to all 58 California counties. Through research and Cooperative Extension in agriculture, natural resources, nutrition, economic and youth development, our mission is to improve the lives of all Californians. Learn more at ucanr.edu.

    About Clif Bar & Company

    Clif Bar & Company is a leading maker of nutritious and organic foods and drinks, including CLIF® Bar energy bar, LUNA®, The Whole Nutrition Bar for Women®; and CLIF Kid®, Nourishing Kids in Motion®. Focused on sports nutrition and snacks for adventure, the family and employee-owned company is committed to sustaining its people, brands, business, community and planet. For more information on Clif Bar & Company, please visit www.clifbar.com, check out our Facebook page at www.facebook.com/clifbar and follow us on Twitter at: www.twitter.com/clifbar.

    — By Pamela Kan-Rice, UC Cooperative Extension

  • Spotted Lanternfly – A Threat to CA Winegrapes (June 11 Webinar)

    The spotted lanternfly (SLF) is an invasive insect from Asia that was first found in Pennsylvania in 2014. The spotted lanternfly can decimate entire grape vineyards and damage fruit orchards, hops, walnuts, hardwoods, and landscape trees. While the SLF has not yet reached California, officials at CDFA are already engaged and the Pierce’s Disease and Glassy-Winged Sharpshooter Board has designated the SLF as a threat to CA winegrapes. Join CAWG, Wine Institute, and Family Winemakers of CA for a webinar on Thursday, June 11th at 10:00am where CDFA will provide an overview of SLF efforts in California, detection and regulatory possibilities, and how growers can be on the lookout for this invasive pest.  
    Presenting will be Dr. Matt Kaiser, Senior Environmental Scientist, CDFA and Dr. Andrew R. Cline, Assistant Director of the Plant Health and Pest Prevention Services Division and Acting Statewide Coordinator for the Pierce’s Disease Control Program of CDFA This webinar is co-hosted by the California Association of Winegrape Growers, Wine Institute, and Family Winemakers of California. We welcome and encourage all members of the wine industry to join us. Register HERE.

  • Protecting American Wheat Fields from Aphids

    Fields of wheat are so associated with the U.S. that they’re featured in the song America the Beautiful as “amber waves of grain.” But those amber fields face a big threat: Russian wheat aphids.

    As their name suggests, these aphids hail from Eurasia. These invasive pests first made their way to Texas in 1986. They’ve since spread to many states and cause billions of dollars of damage to wheat fields. So, crop scientists are desperate to find ways to stop the aphids in their tracks.

    “Our major goal is to find genes connected with the resistance to all Russian wheat aphid types in the U.S. and transfer these genes to best wheat varieties,” says Xiangyang Xu. Xu is a scientist with the U.S. Department of Agriculture who studies these aphids. “When farmers grow these aphid-resistant varieties of wheat, they don’t need to worry about the pest.”

    Unfortunately for farmers, there are at least five major variations of aphids in the U.S. Each type can survive on wheat with different resistance genes.

    Until now, no wheat variety was known that could resist all five types of aphids. That makes genetic resistance the ideal way to protect against the aphids.

    Xu and his team tested over a hundred varieties of wheat to find ones that were resistant to the aphids. The tests included wheat from Afghanistan, Denmark, Iran, Switzerland and the U.S.

    After exposing all wheat varieties to all five types of aphids, researchers observed how much damage the aphids did to the plants. The plants that suffered only minor damage or no damage at all were counted as resistant.

    At the end of the experiment, they found 14 strains of wheat that were able to resist most damage by all five aphid types. The team spotted another nine types of wheat that were able to resist all types of aphids at least some of the time.

    “These wheat varieties are very valuable for breeding durable Russian wheat aphid-resistant wheat cultivars,” says Xu.

    The strongest varieties came from Iran, where both the aphids and wheat are native. That long history of coexistence likely explains why Iranian wheat has developed such strong resistance.

    Now breeders can begin studying how these wheat varieties resist the aphids. And they can use these varieties in breeding programs to provide resistance to American varieties of wheat.

    The aphids feed on the leaves of young wheat plants. This stunts the plant’s growth and can drop yield by up to 60%. Damaged leaves tend to curl around the insects. That curling can protect the aphids from pesticides sprayed on fields. And pesticides are expensive.

    “Pesticides are available to control Russian wheat aphids in the field,” says Xu. “But the considerable costs will significantly reduce farmers’ profit. “

    With these resistant plants identified, the next step is to cross resistant wheat varieties with high performing, but susceptible, varieties.

    “We need to locate the genes first, and then transfer these genes into high-performing wheat varieties in the U.S.,” says Xu.

    The researchers will first find DNA sequences linked with genes creating resistance to track during wheat breeding. Creating new American wheat varieties resistant to all aphid types should take four to five years.

    That will ensure that amber waves of grain stand strong in America for years to come.

    Read more about this research in Crop Science. This work was funded by the United States Department of Agriculture in-house project 3072-21000-009-00D.

  • Research Opp: Improving Our Understanding of Antibiotics in Dairy Farms

    Antibiotics play an essential role in maintaining animal health and productivity. To provide guidance and knowledge on antibiotic use and management practices, it is important to constantly update our understanding on the role of therapeutic antibiotic use and its impact on animal health. A veterinary project is being conducted by UC Davis to better understand antimicrobial resistance patterns in dairy calves, and we are looking for interested farms to participate in the study.

    The project will last around 1-2 months, with up to 2 people visiting the farm a few times a week to collect fecal samples and health data from animals. Any and all data generated will be made available to the owner/manager, and anyone entering the premises is willing to sign a waiver liability release if requested. Identity of participants will remain confidential. No photos will be taken on the facility without consent, and participants are free to back out of the study at any point, if they wish to do so.

    If interested and/or to obtain more information, please contact:
    Katie Lee (UCD, graduate student): lctlee@ucdavis.edu (408-239-9140) Rob Atwill (UCD, Professor): ratwill@ucdavis.edu (530-754-2154)