AgEd Today - Oct 25, 2023 - PDF

AgEdNet.com 1-800-236-7862 AgEd Today for Wednesday, October 25, 2023 TOP OF THE NEWS: Turning the Tables on Tar Spot Fungus in Corn ... $1M Awarded for CDFA Sustainable Pest Management Pilot Study ... The Rio Grande isn't just a border – it's a river in crisis Turning the Tables on Tar Spot Fungus...

AgEdNet.com 1-800-236-7862 AgEd Today for Wednesday, October 25, 2023 TOP OF THE NEWS: Turning the Tables on Tar Spot Fungus in Corn ... $1M Awarded for CDFA Sustainable Pest Management Pilot Study ... The Rio Grande isn't just a border – it's a river in crisis Turning the Tables on Tar Spot Fungus in Corn First reported in Illinois and Indiana in 2015, tar spot has now expanded to include other nearby states, as well as Florida and Canada USDA ARS WASHINGTON -- Agricultural Research Service (ARS) scientists are leaving no stone -- or rather, leaf -- unturned in their search for new ways to counter the fungus that causes tar spot, a yield-robbing disease of field corn in the midwestern United States. The scientists’ studies are in the early stages and more First reported in Illinois and Indiana in 2015, tar spot has now expanded to include other nearby states, as well as Florida and Canada. The disease manifests as raised black spots that mottle the leaves, husks and stalks of susceptible corn varieties, diminishing their photosynthetic ability and, in severe research will be necessary to fully ascertain the fungi and bacteria’s potential to biologically control tar spot in commercial fields when applied during the growing season or to kill overwintering. cases, killing the plants and inflicting grain yield losses of 20 to 60 bushels an acre. Now, however, those same spots may reveal a hidden foe of the fungus that causes tar spot, Phyllachora maydis. The spots, called stromata, are a tough, structural form of the fungus that enables it to survive the winter and release a bevy of spores the following spring that infect the next corn crop. But a team of sharp-eyed scientists with ARS’s National Center for Agricultural Utilization Research in Peoria, Illinois, observed that some stromata specimens they collected failed to germinate -- the “handiwork” of other fungi and bacteria that parasitize the tar spot fungus, potentially opening the door to a biologically based approach to controlling it. The scientists’ observation came while inspecting a research plot of corn near the ARS center in April 2022. Mild outbreaks of tar spot can generally be reduced with synthetic fungicide applications and corn varieties that can tolerate some damage from the fungus. But under the right weather conditions, severe outbreaks can overwhelm these defenses, exacting a costly toll on farmer profits and underscoring the need for additional countermeasures that can be deployed. Fortunately, nature, with its system of checks and balances, offered several different species of fungi and bacteria that grow and reproduce on or inside the fungus’s stromata -- some of which appeared as a whitish fuzz on the stromata when researchers examined them under a microscope in the laboratory. The researchers’ use of DNA-based identification methods revealed that some of the fungi and bacteria were known biological control agents of diseases affecting other crops. In trials, for example, exposure to spores of Gliocladium catenulatum (a commercially available biocontrol fungus) prevented 88 percent of the tar spot fungus’ stromata from germinating. An Alternaria fungus isolated from a tar spot stroma prevented about 45 percent of stromata from germinating. Several research studies have demonstrated that some strains of Alternaria alternataare effective biocontrol organisms that can reduce the damage caused by plant pathogens, said Eric Johnson, a research molecular biologist with the ARS center’s Crop Bioprotection Research Unit in Peoria. Additionally, laboratory assays indicated that the Alternaria strain tested did not cause disease in a susceptible variety of corn when added to damaged portions of leaves. It may be additionally useful in killing overwintering tar spot stromata given that the tested strain grew well at cold temperatures, Johnson added. The scientists’ studies are in the early stages and more research will be necessary to fully ascertain the fungi and bacteria’s potential to biologically control tar spot in commercial fields when applied during the growing season or to kill overwintering. In the meantime, other approaches for managing the disease are also being explored, both in Peoria and at ARS’s Crop Production and Pest Control Research Unit in West Lafayette, Indiana. These include: Examining the basic biology and genetic underpinnings of the tar spot fungus for clues to new ways of controlling it. Developing molecular markers to speed the search for new sources of tar spot resistance in corn. Exploring strategies to make better use of fungicides registered for use against tar spot in corn as part of an integrated approach to managing the disease. Details on the biocontrol potential of the tar spot fungus’s natural rivals were published in the June 2023 issue of the journal Microorganisms by Johnson and co-authors Pat Dowd, Jose Ramirez and Robert Behle -- all with the ARS center’s Crop Bioprotection Research Unit in Peoria. Additional research on biological control of tar spot disease in Peoria is now being funded by the Illinois Corn Growers Association and ARS National Plant Disease Recovery System. The Agricultural Research Service is the U.S. Department of Agriculture’s chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. Each dollar invested in U.S. agricultural research results in $20 of economic impact. Photo credit: U.S. Department of Agriculture, Public domain $1M Awarded for CDFA Sustainable Pest Management Pilot Study The project will develop data on existing practices and utilize it to produce educational courses California Department of Food and Agriculture SACRAMENTO -- CDFA has awarded $1 million in funding to the California Association of Pest Control Advisors to support a two-year project evaluating statewide pest management (SPM) practices. The project will develop data on existing practices and utilize the data to produce new educational courses for pest control advisors (PCAs) – highly trained agricultural consultants who serve at the forefront in plant protection across the state. This award is from the agency’s Sustainable Pest Management Pilot Grant Program. The award is intended to help guide the transition to safer, sustainable pest control practices by assessing current practices in California and enlisting the help of PCAs to promote SPM. The project aligns with the state’s new pest management strategy, “Accelerating Sustainable Pest Management: A Roadmap for California,” which underscores SPM as a whole-system approach that promotes human health, resilient ecosystems, and economic viability in agricultural production. PCAs survey millions of acres annually for pests, nutrient challenges, and irrigation issues, and they recommend strategies to contend with them. PCAs play a pivotal role in promoting SPM in California agriculture and improving producers’ ability to practice SPM. “PCAs are our boots-on-the-ground partners and have first-hand experience with the multitude of pressures that our producers face every day,” said CDFA Undersecretary Christine Birdsong. “The information they will gather through this pilot study will provide a clear analysis of the pests our producers are addressing. This information is essential for understanding the current state of pest management and the impacts of any future changes.” As part of the study, the California Association of Pest Control Advisers will partner with PCAs, commodity groups, growers, and CDFA scientists to collect and analyze pest control practices in pistachio, grape, tomato, and lettuce production. Participating PCAs will receive stipends in exchange for consistently reporting detailed information on their management strategies, including pest surveillance, plant health diagnostics, and recommendations for pesticide applications. And then a curriculum will be developed of SPM Continuing Education courses targeted at filling in gaps in SPM training. The Rio Grande isn't just a border – it's a river in crisis Vianey Rueda, University of Michigan and Drew Gronewold, University of Michigan (THE CONVERSATION) The Rio Grande is one of the longest rivers in North America, running some 1,900 miles (3,060 kilometers) from the Colorado Rockies southeast to the Gulf of Mexico. It provides fresh water for seven U.S. and Mexican states, and forms the border between Texas and Mexico, where it is known as the Río Bravo del Norte. The river's English and Spanish names mean, respectively, "large" and "rough." But viewed from the Zaragoza International Bridge, which connects the cities of El Paso, Texas, and Ciudad Juárez, Mexico, what was once mighty is now a dry riverbed, lined ominously with barbed wire. In the U.S., people often think of the Rio Grande mainly as a political border that features in negotiations over immigration, narcotics smuggling and trade. But there's another crisis on the river that receives far less attention. The river is in decline, suffering from overuse, drought and contentious water rights negotiations. Urban and rural border communities with poor infrastructure, known in Spanish as colonias, are particularly vulnerable to the water crisis. Farmers and cities in southern Texas and northern Mexico are also affected. As researchers who study hydrology and transboundary water management, we believe managing this important resource requires closer cooperation between the U.S. and Mexico. A hidden water crisis For nearly 80 years, the U.S. and Mexico have managed and distributed water from the Colorado River and the Lower Rio Grande – from Fort Quitman, Texas, to the Gulf of Mexico – under the 1944 Water Treaty, signed by presidents Franklin D. Roosevelt and Manuel Avila Camacho. The Colorado River was the central focus of treaty negotiations because officials believed the Colorado basin would have more economic activity and population growth, so it would need more water. In fact, however, the Rio Grande basin has also seen significant growth. For the Rio Grande, the treaty allocates specific shares of water to the U.S. and Mexico from both the river's main stem and its tributaries in Texas and Mexico. Delivery of water from six Mexican tributaries has become the source of contention. One-third of this flow is allocated to the U.S., and must total some 76 million cubic feet (2.2 million cubic meters) over each five-year period. The treaty allows Mexico to roll any accrued deficits at the end of a five-year cycle over to the next cycle. Deficits can only be rolled over once, and they must be made up along with the required deliveries for the following five-year period. These five-year periods, called cycles, are numbered. Cycles 25 (1992-1997) and 26 (1997-2002) were the first time that two consecutive cycles ended in deficit. Like the Colorado River, the Rio Grande has become over-allocated: The 1944 treaty promises users more water than there is in the river. The main causes are persistent drought and increased water demand on both sides of the border. Much of this demand was generated by the 1992 North American Free Trade Agreement, which eliminated most border tariffs between Canada, the U.S. and Mexico. From 1993 through 2007, agricultural imports and exports between the U.S. and Mexico quadrupled, and there was extensive expansion of maquiladoras – assembly plants along the border. This growth increased water demand. Ultimately, Mexico delivered more than the required amount for Cycle 27 (2002-2007), plus its incurred deficit from cycles 25 and 26, by transferring water from its reservoirs. This outcome appeased Texas users but left Mexico vulnerable. Since then, Mexico has continued to struggle to meet its treaty responsibilities and has experienced chronic water shortages. In 2020, a confrontation erupted in the state of Chihuahua between the Mexican National Guard and farmers who believed delivery to Texas of water from the Rio Conchos – one of the six tributaries regulated under the 1944 treaty – threatened their survival. In 2022, people lined up at water distribution sites in the Mexican city of Monterrey, where the population had doubled since 1990. As of 2023, halfway through Cycle 36, Mexico has only delivered some 25% of its targeted amount. Border politics overshadow water shortages As climate change makes the Southwest hotter and drier, scientists predict that water shortages on the Rio Grande will intensify. In this context, the 1944 treaty pits humanitarian needs for water in the U.S. against those in Mexico. It also pits the needs of different sectors against one another. Agriculture is the dominant water consumer in the region, followed by residential use. When there is a drought, however, the treaty prioritizes residential water use over agriculture. The Rio Grande is affected by nearly the same hydroclimate conditions as the Colorado River, which flows mainly through the southwest U.S. but ends in Mexico. However, drought and water shortages in the Colorado River basin receive much more public attention than the same problems on the Rio Grande. U.S. media outlets cover the Rio Grande almost exclusively in stories about immigration and river crossings, such as Texas Gov. Greg Abbott's 2023 decision to install floating barriers in the river at widely used crossing points. The compact that governs use of Colorado River water has widely recognized flaws: The agreement is 100 years old, allocates more rights to water than the river holds, and completely excludes Native American tribes. However, negotiations over the Colorado between compact states and the U.S. and Mexico are much more focused than decisionmaking about Rio Grande water, which has to compete with many other bilateral issues. Adapting to the future As we see it, the 1944 water treaty is inadequate to solve the complex social, economic, hydrological and political challenges that exist today in the Rio Grande basin. We believe it needs revision to reflect modern conditions. This can be done through the minute process, which permits Mexico and the U.S. to adopt legally binding amendments without having to renegotiate the entire agreement. The two countries have already used this process to update the treaty as it pertains to the Colorado River in 2012 and again in 2017. These steps allowed the U.S. to adjust its deliveries of Colorado River water to Mexico based on water levels in Lake Mead, the Colorado's largest reservoir, in ways that proportionally distributed drought impacts between the two countries. In the Rio Grande basin, Mexico does not have similar flexibility. The U.S. also has the ability to proportionally reduce deliveries under a separate 1906 agreement that outlines water delivery from El Paso to Ciudad Juarez. In 2013, for example, Mexico received only 6% of the water it was due under the 1906 Convention. Enabling Mexico to proportionally reduce Rio Grande deliveries according to drought conditions would distribute drought and climate change impacts more fairly between both countries. As we see it, this kind of cooperation would deliver human, ecological and political benefits in a complex and contentious region. All (AP) news items on this page are Copyright © 2023 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed. END