» Publishers, Monetize your RSS feeds with FeedShow: More infos (Show/Hide Ads)
|
|
|
|
Why Invasive Plants Take Over
By Don ComisApril 30, 2009
New research shows that two key causes of plant invasion--escape from natural enemies, and increases in plant resources--act in concert. This result helps to explain the dramatic invasions by exotic plants occurring worldwide. It also indicates that global change is likely to exacerbate invasion by exotic plants.
Agricultural Research Service (ARS) ecologist Dana Blumenthal reached these conclusions after studying 243 European plant species and their fungal and viral pests, both in Europe and in the United States.
The study was published this week in the Proceedings of the National Academy of Sciences.
Blumenthal, based at the ARS Rangeland Resources Research Unit in Fort Collins, Colo., and colleagues at the University of North Carolina and in the Czech Republic showed that fast-growing plant species adapted to moist, nitrogen-rich soils had many fungal and viral pathogens in the areas where the weedy species evolved. Once these species arrived here, they escaped many of their long-time enemies.
Such an escape from numerous enemies is thought to provide exotic species with an advantage over native species still burdened by their enemies. This is the first study, however, to show that whether a plant escapes from a few or an unusually larger number of enemies can be predicted from the type of plant: Exotic species that are fast-growing and weedy are likely to have more enemies to escape from.
Unfortunately, these are the same species most favored by global change. Fast-growing weedy species thrive in environments with ample plant resources. And global change increases key plant resources, such as carbon dioxide and soil nitrogen, through increases in the greenhouse gases carbon dioxide and nitrous oxide, respectively.
Fast-growing, weedy exotic species therefore have a double advantage in today's world. Increases in resources enable them to outcompete slow-growing plants. An escape from an unusually large number of enemies enables them to outcompete even fast-growing native plants. As global change proceeds, continuing increases in resource availability are likely to exacerbate such plant invasions.
The National Science Foundation, the European Union, and the Czech Republic supported the study.
ARS is the principal intramural scientific research agency in the U.S. Department of Agriculture.
|
|
There’s Money in Managing Manure--When It’s Done Right
By Ann PerryApril 29, 2009
New and expanding swine production facilities in North Carolina are required to use manure management systems that meet the strictest environmental performance standards in the nation. Fortunately, Agricultural Research Service (ARS) scientists and cooperators have developed a system that exceeds state benchmarks for controlling pollutants from swine farms.
Soil scientists Matias Vanotti and Ariel Szogi worked with Super Soil Systems USA of Clinton, N.C., to develop a second-generation system that met North Carolina’s environmental standards for manure management. As would be expected for new technologies, significant cost reductions were achieved by innovations and on-farm testing. The revamped system was two-thirds less expensive to build and operate than the first-generation system, which was tested in 2003.
The two researchers work at the ARS Coastal Plains Soil, Water and Plant Research Center in Florence, S.C. For this full-scale project, they collaborated with ARS microbiologist Patricia Millner at the agency’s Environmental Microbial and Food Safety Laboratory in Beltsville, Md., and ARS chemist John Loughrin at the agency’s Animal Waste Management Research Unit in Bowling Green, Ky.
The new on-farm treatment system used solid-liquid separation and nitrogen and phosphorus removal processes. It removed high levels of several pollutants from manure wastewater, including almost all of the pathogens, odor-causing constituents and ammonia. Replacing anaerobic-lagoon-based systems with the new technology also reduced greenhouse gas emissions by 97 percent.
Animal health and production also benefited. Swine daily weight gain increased, feed conversion improved, animal mortality decreased and 5.6 percent more hogs were sold per growing cycle.
Separated manure solids were converted in a centralized facility into composted materials and used for organic plant fertilizer, soil amendments and plant growth media. Producers can also profit from the new system by selling greenhouse gas emission reduction credits and water quality credits.
The new technology could help swine-producing states protect existing jobs and keep the door open for future job expansion. This technology was featured in a chapter of “Manufacturing Climate Solutions: Carbon-Reducing Technologies and U.S. Jobs,” published in 2008 by Duke University’s Center on Globalization, Governance & Competitiveness.
U.S. Patent Application Serial No. 11/820,396 was filed for this system on June 19, 2007.
ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture.
|
|
|
|
A Biocontrol for a Wide-Ranging Thrips
By Dennis O'BrienApril 28, 2009
A pest with a voracious appetite may have met its match in a predatory mite being evaluated as a biocontrol agent by Agricultural Research Service (ARS) scientists in Fort Pierce, Fla. in collaboration with University of Florida researchers.
The chilli thrips is an invasive pest that feeds on leaves, turns them brown, kills new growth and attacks up to 150 crops, including peppers, strawberries, tomatoes, peanuts, cotton and a variety of ornamentals.
Detected in Palm Beach County, Fla. in 2005, it has spread to 24 Florida counties and parts of Texas, damaging roses and other ornamentals in both states. Left unchecked, it could reach west to California and north along the Pacific Coast to Canada, causing losses of up to $3.8 billion annually.
Pesticides are effective, but the chilli thrips may develop resistance with repeated treatments, and pesticides are not an option for organic nurseries and gardeners, according to entomologist Cindy L. McKenzie, at the ARS U.S. Horticultural Research Laboratory in Fort Pierce.
Researchers at Fort Pierce and the University of Florida have turned to two mites, Neoseiulus cucumeris and Amblyseius swirskii, which have been used commercially to combat other pests since at least 2005. The researchers put 30 adult chilli thrips on ornamental pepper plants in greenhouse and outdoor settings, waited a week for thrips larvae to hatch and, in separate treatments, released 30 mites of each species on the plants. They checked the plants weekly for four weeks.
Their results, published in Biological Control, showed that the mites--particularly A. swirskii--significantly reduced the number of thrips. A. swirskii left no more than one thrips insect per leaf. That compared with up to 60 thrips larva found on leaves of untreated pepper plants. The work was funded in part by the American Floral Endowment and the Floriculture and Nursery Research Initiative.
The researchers have set up a chilli thrips website for gardeners and commercial growers at http://www.mrec.ifas.ufl.edu/lso/thripslinks.htm.
ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture.
|
|
National Arboretum Unveils First Solar-Powered Irrigation System
By Stephanie YaoApril 27, 2009
The U.S. National Arboretum is "going green" with the installation of its first solar-powered drip irrigation system that will save electricity and water at the 446-acre facility operated by the Agricultural Research Service (ARS) in Washington, DC.
The new system is part of a long-range plan to update and improve the arboretum grounds. Future plans include installing a larger solar collector near the National Capitol Columns and solar shingles on the Arbor House, which houses the gift shop and visitor restrooms.
Installation of the new system marked the end of a week-long workshop conducted by students and faculty from Alfred State College of the State University of New York. The workshop—attended by arboretum staff, contractors and homeowners—provided hands-on instruction on how to construct and use the system and its many benefits.
Located in Nursery 5, which is used to conduct research aimed at the development of improved trees for landscape use, the new system consists of six solar panels that collect sunlight, a battery that stores the energy, and a converter box that converts the stored energy into electricity used to run the nursery's drip-irrigation system. Because of the nursery's remote location, installing solar panels was less expensive than running an electrical line from the main power source, approximately a half mile away. As a result, the arboretum will see immediate savings on costs.
The latest project is a staff-driven effort to cut energy costs and conserve resources. The new system took less than one year to complete. Arboretum Director Tom Elias first met Alfred State representatives during the U.S. Department of Agriculture's (USDA) Bio Energy Awareness Days (BEAD II) exhibition held at the arboretum last June. The meeting led to a five-year cooperative agreement to develop and install green technologies that will help the arboretum reduce its carbon footprint.
The arboretum's new system serves as a model for more energy-efficient landscape gardening. Solar power can be used in urban and suburban areas and is applicable to all types of power systems. Gardeners can use it to power water features, such as fountains and waterfalls, and irrigation systems.
ARS is the principal intramural scientific research agency of the USDA.
Read the magazine story to find out more. |
|
|
Arcobacter: Foodborne Pathogen's Genome Exposed
By Marcia WoodApril 24, 2009
If a little-known microbe called Arcobacter butzleri has contaminated the water you drink or the food you eat, this troublesome pathogen could make you sick. Symptoms include diarrhea, stomach cramps, nausea, vomiting and fever, all of which can become chronic if left untreated.
But investigations by Agricultural Research Service (ARS) microbiologist William G. Miller and colleagues may speed discovery of innovative ways to control this microbe.
In 2007, Miller and co-researchers deciphered the sequence of the pathogen's genetic material, or genome. This work was a scientific "first" for any of the world's Arcobacters. Based at the ARS Western Regional Research Center in Albany, Calif., Miller did the research with co-investigators there and with others in the United States and abroad.
Since then, Miller has employed the genomic data in developing what's known as a "typing method" to differentiate A. butzleri from look-alike species, and to distinguish specific strains within those species. Medical professionals, public health agencies and researchers can use it when they're tracking the source of foodborne-illness outbreaks. In the past, for example, A. butzleri has been implicated as a cause of such outbreaks in Europe and Southeast Asia.
Read more about this research in the April 2009 issue of Agricultural Research magazine.
ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture.
Read the magazine story to find out more. |
|
|
|
Technologies Improve FMD Detection and Control
By Laura McGinnisApril 23, 2009
Improving the detection and control of foot and mouth disease (FMD) in cattle could result from technology being developed and tested by Agricultural Research Service (ARS) scientists.
The United States hasn't had an outbreak of FMD since 1929, but being prepared for an outbreak is a priority for the U.S. government.
One study used infrared cameras to detect elevated hoof temperatures, a symptom of FMD in cattle. That work was conducted by research leader Luis Rodriguez, microbiologist Juan Pacheco and research fellow Kaitlin Rainwater-Lovett with ARS at the Plum Island Animal Disease Center at Orient Point, N.Y., in collaboration with University of Minnesota biologist Craig Packer.
Infrared technology could detect elevated temperatures up to two days before cattle develop clinical signs. Cheaper and faster than existing screening methods, this technology could allow scientists and veterinarians to identify potentially infected cattle in large groups, without examining animals individually.
The ARS scientists have also collaborated with the biotechnology company Tetracore to develop a test that can detect RNA from the FMD virus in less than two hours. In the event of an FMD emergency, laboratories throughout the United States could use this technology to diagnose samples rapidly.
In related work, ARS chemist Marvin Grubman and his colleagues are making improvements to the FMD vaccine they developed. The vaccine can be produced without using infectious FMD materials, which means it can be produced on the U.S. mainland without the need for expensive, high-containment production facilities.
Tests have shown that the vaccine becomes effective a mere seven days after it's been administered. Although this is one of the fastest vaccines available, Grubman and his colleagues wanted faster protection. After all, a lot can happen in seven days, particularly during an outbreak. In a recent study, Grubman found that proteins called interferons can offer protection while animals are developing an antibody response to the vaccine, increasing their resistance.
ARS, the U.S. Department of Homeland Security and biopharmaceutical company GenVec, Inc., in Gaithersburg, Md., are now collaborating to develop the new FMD vaccine for inclusion in the U.S. Veterinary Vaccine Stockpile. They are also working to combine the interferons and the FMD vaccine so they can be administered concurrently.
Read more about this research in the April 2009 issue of Agricultural Research magazine.
ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture.
|
|
|
|
Organic Dairy Manure May Offer Fertilizer Option
By Ann PerryApril 22, 2009
Dairy cows that produce USDA-certified organic milk also produce manure that may gradually replenish soil nutrients and potentially reduce the flow of agricultural pollutants to nearby water sources, according to findings by Agricultural Research Service (ARS) scientists and colleagues.
Cows on organic dairy farms generally consume forage feeds cultivated on soils that are fertilized with manure and compost rather than manufactured fertilizers. This organic management, in turn, may significantly affect how easily nutrients are converted in soil into forms readily taken up by crops.
Working with colleagues at the ARS New England Plant, Soil, and Water Laboratory in Orono, Maine, and elsewhere, chemist Zhongqi He showed that conventional and organic dairy manures from commercial dairy farms differed in concentrations of plant nutrients, including phosphorus, metals and minerals.
The team used two different types of nuclear magnetic resonance (NMR) to pinpoint these differences. Solution NMR spectroscopy is already widely used to analyze phosphorus content in manure. For this study, the scientists also analyzed manure content using solid-state NMR spectroscopy, which is especially effective at finding unique “signatures” of the different kinds of metals and minerals.
The researchers found that the two types of manure had at least 17 different chemical forms of phosphorus that varied in concentrations. The organic dairy manure had higher levels of phosphorus, calcium, potassium, manganese, zinc and magnesium.
Organic dairy manure also contained more types of phosphorus found in association with calcium and magnesium. Such forms are comparatively slow to dissolve and would thus gradually release the nutrients. Slow-release fertilizers generally increase the likelihood that they eventually will be taken up by crops, rather than being washed out of fields into nearby surface or groundwater sources.
Because of this, slow-release fertilizers often can be applied at comparatively low rates. Manure produced by cows in organic production systems may show similar characteristics compared to manure from conventional systems.
ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture.
Read the magazine story to find out more. |
|
|
ARS Investigate Genes Involved in Forming Plum Pits
By Sharon DurhamApril 21, 2009
Agricultural Research Service (ARS) scientists are making progress in determining the genes that control pit formation in plums—the first step in a project to develop pitless varieties of this fruit.
ARS molecular biologists Chris Dardick and Ann Callahan and Prunus breeder Ralph Scorza at the ARS Appalachian Fruit Research Station in Kearneysville, W.Va., discovered that a set of genes necessary for production of lignin is rapidly turned on specifically in pit tissue—not the flesh or skin—just before hardening. Then these genes quiet down just as quickly after the stone hardens.
Lignin is a material involved in the formation of pits in stone fruit. Fruit pits consist of the seed and the hard woody material, or stone, surrounding the seed.
The researchers' goal is to establish techniques to stop the genes' activity and prevent hardening of the pit, thus producing a pitless plum that would be more appealing to consumers. Pitless fruit would be a premium product that could provide higher income for growers and could increase consumption of these nutritious foods.
The idea of pitless fruits is not new. In the early 1900s, Luther Burbank, a prolific horticulturalist, crossed a partially stoneless wild plum with California French prune varieties. These crosses led to commercial-quality fruit that almost completely lacked the stone, but still contained the seed. The group used samples of Burbank's crosses for their work.
The research team engineered Burbank's stoneless variety with an early-flowering trait that will greatly speed up the breeding program. The resulting fruit has remarkably little stone tissue, but further improvements are needed to make it edible, according to Dardick. Early flowering will substantially shorten the time it takes to test the strategies that may lead to pitless plums.
According to Dardick, if successful, the research may be applicable to other stone fruits, such as cherries, peaches, nectarines and apricots.
Read more about this research in the April 2009 issue of Agricultural Research magazine.
ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture.
|
|
ARS Dietary Supplement Data Supports Nutrient Intake Assessments
By Rosalie Marion BlissApril 20, 2009
More than 50 percent of adults in the United States consume dietary supplements, according to experts. Now, a newly launched resource, the Dietary Supplement Ingredient Database (DSID), will help researchers improve estimates of the U.S. population's total nutrient intakes. That's because the DSID was developed to improve estimates of the U.S population's nutrient intakes based not only on the beverages and foods people consume, but also on their dietary supplement intake.
The Agricultural Research Service (ARS) Nutrient Data Laboratory at the Maryland-based Beltsville Human Nutrition Research Center and the National Institutes of Health Office of Dietary Supplements (ODS) planned and developed the DSID with other government collaborators. Joanne M. Holden is the ARS laboratory's research leader, and Paul M. Coates is the ODS director.
The collaborators rolled out the new public-access database during the annual meeting of the American Society for Nutrition, held in conjunction with the Experimental Biology 2009 meeting this week in New Orleans, La. The conference is sponsored by member societies of the Federation of American Societies for Experimental Biology.
The database provides statistical estimates—based on chemical analysis—of the nutrient content of selected ingredients in dietary supplements, compared with label-reported ingredient levels. The first release of the DSID provides estimated levels of 18 vitamin and mineral ingredients derived from analytical data for 115 representative unspecified adult multivitamin/multimineral supplements (MVMs).
ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture (USDA). The DSID has been developed as a complement to the USDA-ARS National Nutrient Database for Standard Reference, the source of food-nutrient data used for the ARS What We Eat in America study component of the National Health and Nutrition Examination Survey.
Total nutrient intake data is based on the foods, beverages and dietary supplements people consume. The DSID, as a resource, will increase researchers' ability to investigate relationships between dietary supplement intakes and health indicators in future applied research studies.
To access DSID-1, go to:
http://dietarysupplementdatabase.usda.nih.gov
Future releases are planned to include evaluations of nutrients in other commonly used supplements.
Read the magazine story to find out more. |
|
|
Pest-Resistant Potato on Tap
By Jan SuszkiwApril 17, 2009
A new russet potato germplasm line developed by Agricultural Research Service (ARS) scientists and collaborators could help cut the cost of using chemical fumigants to fight Columbia root-knot nematodes (CRN).
The wormlike pests are problematic in the Pacific Northwest, where two-thirds of America's potatoes are grown, as well as in Florida. Although fumigating the soil before planting time diminishes the pest's numbers, the practice isn't cheap, with some chemicals costing $300 per acre. Beneficial, soil-dwelling insects can also be harmed, according to geneticist Chuck Brown, with the ARS Vegetable and Forage Crops Research Unit in Prosser, Wash.
Thanks to genetic resistance, the new russet potato, PA99N82-4, offers a way to naturally protect the roots and tubers against nematode feeding. Putting that resistance to work hasn't been easy, though.
Brown and colleagues conducted painstaking screening of material from Solanum bulbocastanum and other wild species kept at the ARS U.S. Potato Genebank in Sturgeon Bay, Wis. Because wild and cultivated potatoes are chromosomally incompatible, the researchers resorted to bridging, a technique that fused S. bulbocastanum and domesticated potato cells together, which forced the DNA of both to combine. The cells were then stimulated to become plantlets. Later, "backcrossing" was used to eliminate unwanted traits (like tiny tubers and poor taste) from CRN-resistant plants that the researchers had created.
They also used DNA marker technology to identify plants harboring the S. bulbocastanum gene for resistance, namely RMc1(blb). Normally, resistance levels are determined by inoculating potted plants with nematodes, waiting seven weeks and removing and washing the roots so the pests' eggs can be counted. Use of DNA marker streamlines this process and identifies resistant plants in one day, according to Brown.
PA99N82-4 will undergo two more years of field-testing before it is released for use in developing commercial varieties.
Read more about the research in the April 2009 issue of Agricultural Research magazine.
ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture.
|
Read the magazine story to find out more. |
|
|
|
|
Knowing Where to Look for Invasive Leafy Spurge
By Don ComisApril 16, 2009
The invasive weed leafy spurge is now easier to locate, thanks to a new detection method developed by Agricultural Research Service (ARS) scientists and their cooperators.
ARS physical scientist Raymond Hunt developed and tested the method using NASA's advanced hyperspectral sensor, the Airborne Visible Infrared Imaging Spectrometer (AVIRIS). Hunt works at the ARS Hydrology and Remote Sensing Laboratory in Beltsville, Md.
Leafy spurge (Euphorbia esula L.) is a noxious invasive weed that causes more than $200 million in losses annually in the Great Plains and western United States. It displaces native vegetation and spreads both by seeds and by underground rhizomes. Shoots produce a milky-white sap that is toxic to cattle and horses. Infestations can be controlled by pesticides, goats or Aphthona flea beetles.
Hunt and his colleagues were among the first researchers to detect invasive weeds by using algorithms developed to detect minerals in rocks and soil by hyperspectral remote sensing. The method works by analyzing visible and near-infrared light from the sun, reflected off vegetation, and back to the AVIRIS sensor aboard NASA aircraft.
They used the algorithms to detect leafy spurge during its flowering stage, from June to July.
Different colors of light are reflected from the showy yellow-green flowers compared to the surrounding grass and other green vegetation. When tested against field data, the method proved to be 85 to 95 percent accurate--much higher than other methods of remote sensing tested in the same area.
Working with USDA's Forest Service, Hunt is also refining the Weed Invasion Susceptibility Prediction (WISP) model to show areas where spurge and other invasive species are likely to grow.
When the model is ready for national use, Hunt would like to see it published on Google Earth or some other Internet site.
Read more about this research in the April 2009 issue of Agricultural Research magazine.
ARS is the principal intramural scientific research agency in the U.S. Department of Agriculture.
Read the magazine story to find out more. |
|
|
Palm Oil Not a Healthy Substitute for Trans Fats
By Rosalie Marion BlissApril 15, 2009
Manufacturers are now required to state on food labels the amount of trans fatty acids, also called hydrogenated fats, in packaged foods. Both trans fatty acids and saturated fatty acids are associated with elevated heart disease risk factors.
Now, authors of an Agricultural Research Service (ARS)-supported study have addressed the question of whether palm oil, whose functional characteristics are similar to trans fats, would be a good substitute for partially hydrogenated fat.
Trans fatty acids (trans fats) are created during a hardening process called hydrogenation, which serves to make oils suitable for use in products that require solid fats, such as baked goods and breakfast bars. The clinical trial was designed to compare—on heart disease risk—the effect of four different oils as they are commonly consumed.
Lead scientist Alice H. Lichtenstein and colleagues conducted the study. She is with the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, Mass.
Fifteen adults, both male and female, volunteered for the study. Their levels of LDL "bad" cholesterol were moderately high at 130 milligrams per deciliter of blood or above, and all were aged 50 or older. They each consumed each of four 35-day experimental diets. The fats tested were partially hydrogenated soybean oil (moderately high in trans fat), palm oil (high in saturated fat), canola oil (high in monounsaturated fat), and soybean oil (high in polyunsaturated fat).
The findings suggest that consuming either of the diets enriched with equivalent high amounts of palm oil or partially hydrogenated soybean oil would result in similar unfavorable levels of LDL cholesterol and apolipoprotein B (a protein, attached to fat particles, that carries bad cholesterol throughout the bloodstream). That's when compared to consuming either of the diets enriched with canola and soybean oils high in monounsaturated and polyunsaturated fats, respectively.
The results suggest that palm oil would not be a good substitute for trans fats by the food industry, the authors wrote.
Read more about this research in the April 2009 issue of Agricultural Research magazine.
ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture.
|
|
ARS Food and Nutrition Research Briefs Issued
By Kim KaplanApril 14, 2009
Neutralizing an acid-producing diet may be an important key to reducing bone breakdown while aging. That's among the new findings noted in the most recent issue of the Agricultural Research Service's (ARS) Food and Nutrition Research Briefs and its Spanish-language edition, Informe de investigaciones de alimentos y nutrición.
View the English edition at http://www.ars.usda.gov/is/np/fnrb/fnrb0409.htm.
The popular online newsletter reports discoveries from researchers at ARS laboratories nationwide.
Among other findings, the current issue reports:
-- Supplemental UV-A plus UV-B light can greatly increase the carotenoid and chlorophyll concentrations of some green leaf lettuce varieties in the greenhouse.
-- A diet rich in the berry and grape compound pterostilbene was effective in reversing cognitive decline and improving working memory in aged laboratory rats.
-- ARS has developed a new nanotechnology-based biological sensor that detects Salmonella bacteria in lab tests.
The ARS Food and Nutrition Research Briefs is offered with color photos and illustrations on the Web. And by clicking the "subscribe" link on the newsletter's home page, readers can sign up for two e-mail options: They can receive the full text of the newsletter by e-mail, or simply an advisory that a new issue has been posted to the Web.
ARS is the U.S. Department of Agriculture's chief scientific research agency.
|
|
ARS Releases Iceberg Lettuce Breeding Lines Resistant to Bacterial Leaf Spot
By Stephanie YaoApril 13, 2009
Seven new iceberg lettuce breeding lines with resistance to bacterial leaf spot (BLS) have been released by Agricultural Research Service (ARS) scientists.
BLS, caused by the pathogen Xanthomonas campestris pv. vitians, is an important disease of lettuce in California. Iceberg lettuce is the most popular type of lettuce eaten in America. Nearly all of the lettuce consumed in the United States is produced domestically. Two states, California and Arizona, produce more than 90 percent of the country's commercial lettuce.
Occurring on both leaf and head lettuce varieties, BLS thrives in wet, cool conditions. It is most serious in early spring and late fall, when it is most likely to rain in California. BLS causes black spots to form on lettuce leaves. These black spots can merge and create papery, brown-to-black patches on the head. Upon harvest, farmers must peel and discard the leaves to remove the patches, resulting in smaller heads that command less money.
BLS is difficult to prevent because the disease is highly dependent on weather conditions. Farmers can spray their lettuce crops with pesticides, but the chemicals have to be applied before symptoms develop, which is impractical. Because BLS is sporadic and unpredictable, these preemptive sprayings would be unnecessary in most seasons and lead to increased production costs. Therefore, according to ARS geneticist Ryan Hayes, creating disease-resistant breeding lines is the most efficient and cost-effective tool to manage BLS in lettuce.
Hayes, along with geneticist Edward Ryder (now retired) and plant pathologist Carolee Bull, developed the seven new breeding lines at the ARS Crop Improvement and Protection Research Unit in Salinas, Calif. Similar in appearance to the famous ?Salinas' variety created by Ryder, these lines are the first western shipping-type icebergs with commercially useful levels of resistance to BLS. ARS provides these lines to seed companies, which in turn use them to develop new iceberg varieties for commercial use.
Limited samples of seed from these breeding lines are available from the ARS unit in Salinas to researchers and seed companies.
ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture.
Read the magazine story to find out more. |
|
|
Byproducts of Biofuels Could be Economically Viable for Growers
By Alfredo FloresApril 10, 2009
Agricultural Research Service (ARS) scientists have found environmentally and economically sound uses for the byproducts of biofuel production.
Animal scientist William Dozier, formerly with the ARS Poultry Research Unit in Mississippi State, Miss., has been working with colleagues at the ARS Swine Odor and Manure Management Research Unit in Ames, Iowa, and Iowa State University (ISU) to find ways to supplement animal diets with glycerin. Glycerin, a biofuel byproduct, contains energy-providing nutrients for animals.
Dozier and ISU colleague Kristjan Bregendahl evaluated the use of glycerin supplements in poultry feed. Dozier primarily dealt with broilers, which are chickens raised specifically for meat production, and gave glycerin-supplemented poultry feed to broilers that were 7 to 45 days old.
Dozier evaluated the apparent metabolizable energy (AME) intake—a standard measure of energy—for the study group and for a control group that ate a standard diet. The youngest chicks, aged 7 to 10 days, showed a higher AME intake than the control group. However, the two groups showed no significant differences in the amount of feed they consumed, body weight, or the amount of energy lost in feces and urine (energy excretion).
The second group of broilers, aged 21 to 24 days old, that consumed glycerin feed supplements showed no difference in body weight, energy excretion, and AME. However, their feed intake and the amount of energy provided by the diet intake (gross energy) increased when glycerin supplementation increased. The oldest broilers, aged 42 to 45 days old, showed increases in feed consumption, gross energy, and AME.
Dozier notes that from a nutritional standpoint, this technology can serve as an alternative dietary energy source that could result in lower feed costs. Swine and poultry producers are very interested in supplementing livestock feed with glycerin, in part because the corn grain and soybeans that used to be fed to livestock are now being used for biofuel production. This way, the crops can be used for both biofuels and for livestock feed.
Read more about this research in the April 2009 issue of Agricultural Research magazine.
ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture.
|
|
Agriculture Secretary Vilsack and First Lady Michelle Obama Highlight Healthy Eating
By Sandy Miller HaysApril 9, 2009
WASHINGTON, April 9, 2009—Agriculture Secretary Tom Vilsack joined First Lady Michelle Obama and a group of 5th graders on the South Lawn of the White House today to talk about healthy eating, the availability of locally grown fruits and vegetables, and bees.
"Growing your own fruits and vegetables is one of the best ways to have healthy food," Vilsack said. "Working in a garden is a great way to stay physically active and maintain a healthy body. And the U.S. Department of Agriculture (USDA) is helping schools make sure that every student in America has a healthy and nutritious lunch to eat at school."
This July, USDA will be providing two types of parasite-resistant honey bees developed by USDA scientists to pollinate the plants in the new White House garden this summer. Both of these bees are rapidly gaining in popularity with bee keepers.
Honey bees enhance any garden because they increase the yields of plants that require pollination, they produce honey, and they are one of Nature's most fascinating creatures to observe. Unfortunately, parasitic mites cause serious health problems for most varieties of honey bees, and many beekeepers must use pesticides to combat the mites in the hives. But the USDA-developed bees are mite-resistant, offering a more natural, organic alternative for the White House garden.
Honey bees are crucial to American agriculture, adding some $15 billion in value in the nation's crops, particularly specialty crops such as almonds and other nuts, berries, fruits, and vegetables. In California, the almond crop alone uses 1.3 million colonies of bees, approximately one half of all honey bees in the United States, and this need is projected to grow to 1.5 million colonies by 2010.
Scientists with the Agricultural Research Service (ARS), USDA's principal intramural scientific research agency, developed the two types of mite-resistant honey bees. One type is highly resistant to the parasitic mite Varroa destructor, commonly known as the varroa mite. The bees have a trait called "varroa-sensitive hygiene" which prompts the worker bees to detect and remove infested bees from the nest, eliminating the need for chemical help to control the mites.
The second type of mite-resistant honey bees is based on a strain of honey bees from Russia which are naturally resistant not only to varroa mites, but also to tracheal mites, which infest the breathing tubes of the bees. These bees are also highly tolerant of cold weather and require less artificial feeding than typical honey bees.
The Russian bees were brought to the United States by Thomas Rinderer, research leader at ARS' Honey Bee Breeding, Genetics and Physiology Research Unit at Baton Rouge, La., where studies have been under way on the bees since the mid-1990s. Rinderer and other ARS scientists will collaborate with White House staff on installation of the USDA bees in the White House garden.
For the past eight years, breeder queens of the Russian-derived and varroa-sensitive hygienic bees have been released to the beekeeping industry. In 2008, a breeders' group called the Russian Honeybee Breeders Association, Inc., was formed to supply the Russian-derived queens throughout the U.S. beekeeping industry, and demand is outstripping supply.
Both types of mite-resistant USDA bees are good pollinators and easy to keep alive because of their hardiness, thus helping ensure the success of the new White House garden.
|
|
New Issue of Healthy Animals Now Online
By Laura McGinnisApril 9, 2009
The Agricultural Research Service (ARS) today posted a new issue of Healthy Animals. This quarterly online newsletter compiles ARS news and expert resources on the health and well-being of agricultural livestock, poultry and fish.
Each quarter, one article in Healthy Animals focuses on a particular element of ARS animal research. The current issue examines catfish research conducted by scientists at the Catfish Genetics Research Unit in Stoneville, Miss.
Other research highlighted in this issue includes:
- Supportive supplements: The benefits of feeding dried distiller's grains to piglets.
- Colonial conservation: Adding genetic material from historic sheep to the national collection.
- Barley for bovines: Two new, high-yielding barleys.
Professionals interested in animal health issues may want to bookmark the site as a resource for locating animal health experts. An index lists ARS research locations covering approximately 70 animal health topics. These range from specific diseases, such as Lyme disease, to broad subjects like nutrition or parasites. The site also provides complete contact information for the more than 25 ARS research groups that conduct studies aimed at protecting and improving farm animal health.
To receive an e-mail alert about each future issue's posting online, contact Laura McGinnis, ARS Information Staff (301-504-1654, laura.mcginnis@ars.usda.gov), or sign up online.
ARS is the principal intramural scientific research agency in the U.S. Department of Agriculture.
|
Read the magazine story to find out more. |
|
|
|
|
Helping Fruit Fight Back
By Ann PerryApril 8, 2009
Studies by Agricultural Research Service scientists (ARS) indicate that cherries, red raspberries and apples share key genetic traits for disease resistance. These findings could help plant breeders develop more robust produce varieties that can better withstand the pathogens that plague them.
ARS computational biologist Angela Baldo conducted genetic surveys of the three fruits to find markers for locating resistance genes that battle diseases and other stresses. Baldo works at the ARS Plant Genetic Resources Unit in Geneva, N.Y.
Cherries, apples and red raspberries are all members of the Rosaceae plant family and contain resistance genes found in many other plants. Working with several colleagues, Baldo found 75 markers for resistance genes in red raspberry. The majority of the markers were unique, but they were anywhere from 50 to 87 percent similar to the markers from other Rosaceae species.
One of the markers was linked genetically to Phytophthora root rot resistance. This discovery might someday help plant breeders develop hardier and more marketable varieties of red raspberry.
Baldo also contributed to the identification of 90 resistance gene markers from sweet and sour cherry cultivars with different levels of resistance to cherry leaf spot and powdery mildew. The markers were compared with other Rosaceous markers that researchers have already linked with resistance to a range of pathogens.
The preliminary studies suggest there may be similarities between peach resistance gene markers linked to sharka, also known as plum pox, and cherry resistance gene markers linked to powdery mildew. If additional research confirms these findings, they could support more efficient methods for mapping resistance genes.
Baldo and colleagues also helped find three new groups of resistance gene markers in some 300 wild apple accessions. Plans are under way to map these gene markers and assess their links to regions of the apple genome that convey resistance to fire blight, apple scab and powdery mildew.
Read more about this research in the April 2009 issue of Agricultural Research magazine.
ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture.
| Read the magazine story to find out more. |
|
|
|
|
Salmonella Strain's Path to Virulence Uncovered
By Sharon DurhamApril 7, 2009
Agricultural Research Service (ARS) scientists have uncovered genetic evidence about the evolutionary path that transformed Salmonella enteritidis from an innocuous bacterium into a virulent pathogen.
S. enteritidis, like many bacteria, reproduces very quickly--every 20 minutes in optimal conditions, according to veterinary medical officer Jean Guard-Bouldin in the ARS Egg Safety and Quality Research Unit in Athens, Ga.
Such a fast reproductive pace allows the organism to accumulate genetic variations. Only healthy competitors go on to reproduce, survive and develop the mechanisms needed to infect the egg. Using DNA analysis, Guard-Bouldin is looking at evolutionary evidence to determine how some S. enteritidis strains became pathogenic. Studying how S. enteritidis evolves and infects hens on the farm may someday help reduce levels of infection.
Guard-Bouldin and her colleagues found S. enteritidis strains to be so similar genetically that they appear identical, yet they may behave differently inside the hen. To distinguish between the apparently identical genomes, researchers must use a technique called "whole-genome mutational mapping" to analyze multiple strains.
Through these analyses, the researchers developed a timeline of when S. enteritidis first became capable of getting inside the egg from hen reproductive organs--approximately 36 years ago. It appears that a large-scale swap of DNA between strains, in association with the emergence of egg contamination, created a hybrid strain of S. enteritidis.
This hybrid strain had the ability to contaminate the internal contents of eggs. Later, it also split very quickly into two lineages, each carrying one virus. Both of the newly split lineages continued to evolve and eventually began to vary in their ability to contaminate eggs and to survive on the farm.
Read more about this research in the April 2009 issue of Agricultural Research magazine.
ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture.
|
Read the magazine story to find out more. |
|
|
|
|
Salmonella Strain's Path to Virulence Uncovered
By Sharon DurhamApril 7, 2009
Agricultural Research Service (ARS) scientists have uncovered genetic evidence about the evolutionary path that transformed Salmonella enteritidis from an innocuous bacterium into a virulent pathogen.
S. enteritidis, like many bacteria, reproduces very quickly--every 20 minutes in optimal conditions, according to veterinary medical officer Jean Guard-Bouldin in the ARS Egg Safety and Quality Research Unit in Athens, Ga.
Such a fast reproductive pace allows the organism to accumulate genetic variations. Only healthy competitors go on to reproduce, survive and develop the mechanisms needed to infect the egg. Using DNA analysis, Guard-Bouldin is looking at evolutionary evidence to determine how some S. enteritidis strains became pathogenic. Studying how S. enteritidis evolves and infects hens on the farm may someday help reduce levels of infection.
Guard-Bouldin and her colleagues found S. enteritidis strains to be so similar genetically that they appear identical, yet they may behave differently inside the hen. To distinguish between the apparently identical genomes, researchers must use a technique called "whole-genome mutational mapping" to analyze multiple strains.
Through these analyses, the researchers developed a timeline of when S. enteritidis first became capable of getting inside the egg from hen reproductive organs--approximately 36 years ago. It appears that a large-scale swap of DNA between strains, in association with the emergence of egg contamination, created a hybrid strain of S. enteritidis.
This hybrid strain had the ability to contaminate the internal contents of eggs. Later, it also split very quickly into two lineages, each carrying one virus. Both of the newly split lineages continued to evolve and eventually began to vary in their ability to contaminate eggs and to survive on the farm.
Read more about this research in the April 2009 issue of Agricultural Research magazine.
ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture.