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Utah Science

Volume 61

Number 2

Winter 2002


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KERMIT L. HALL,

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If you diagramed Sherm Thomson’s approach to questions about plant pathology the resulting illustration might end up looking like an outline of the trees he often studies; a central idea or question branching off into new ideas, experiments twisting those branches in new directions, an observation planting a seed from which new ideas and questions emerge. “I love to hear about what Sherm has going on because he never thinks in a straight line,” a fellow plant scientist said between field day presentations at the Experiment Station’s Kaysville farm. As if to prove his colleague’s point, Thomson told a story about watching orchardists in Japan as they carefully dabbed mud on the trunks and branches of fruit trees. After a brief conversation, complicated by language barriers, Thomson learned that they were using the mud to treat fungal cankers in the trees. The encounter set him thinking about fungal cankers that are commonly pruned out of trees – particularly stone fruit trees – and wondering if a treatment like the mud might allow growers to save more trees in a non-invasive way. His initial brainstorms about wrapping trees or covering the cankers with a poultice met with quizzical looks from graduate students who admit their first reaction was to ask, “You

want us to do what?” But in the name of science several Experiment Station peach trees infected with Cytospora fungus and exhibiting the oozing cankers that accompany the disease were treated with poultices last summer. This first round of experiments yielded enough promising results to justify Thomson and his graduate students contemplating modifications that will likely cover several seasons of study. Other experiments under Thomson’s direction are aimed at finding antibiotic-free methods of controlling fire blight in apples and pears; one resulting treatment that make passersby wonder if a modern artist with a penchant for plastic wrap had gotten loose in the orchard. But the experiment worked. (See related story, page 2). Plant pathologists know a lot about fire blight, but not enough to cure it or prevent it consistently. Because the disease is less common in hot weather, Thomson wondered if heating affected trees might kill the bacteria. He began thinking about ways to heat trees. At that time, he was involved in research that required wrapping trees in plastic to keep out pollinating insects and found working under the wrapped trees a lot like working in a sauna. Bingo! A new idea took root and since then Thomson has been heating trees by wrapping them in plastic to kill the fire blight bacteria lurking inside. “I’ve studied fire blight for 30 years,” Thomson said. “It’s a very fascinating disease. I mean, think about it. Here you have bacteria with no brain. It doesn’t have feet, arms or hands. Doesn’t have a mouth. It can’t speak, and yet it’s got all of us knocked against the ropes most of the time. It just always seems to adapt and get the upper hand.” Maybe that’s one reason scientists like Thomson don’t think in straight lines. The problems they tackle seldom follow a predictable course.

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“I love to hear about, what Sherm has going on because he never thinks in a straight line.”

PRESIDENT, UTAH STATE UNIVERSITY

H. PAUL RASMUSSEN, DIRECTOR, UTAH AGRICULTURAL EXPERIMENT STATION

UTAH SCIENCE will be sent free on request in the United States. Subscriptions mailed to individuals and institutions in other countries cost $35.00 annually which includes shipping and handling. Please include a mailing label from a recent issue of UTAH SCIENCE with any request for change of address. To avoid overuse of technical terms, sometimes trade names of products or equipment are used. No endorsement of specific products or firms named is intended, nor is criticism implied of those not mentioned. Articles and information appearing in UTAH SCIENCE become public property upon publication. They may be reprinted provided that no endorsement of a specific commercial product or firm is stated or implied in so doing. Please credit the authors, Utah State University, and UTAH SCIENCE. Equal Opportunity in employment and education is an essential priority for Utah State University, and one to which the University is deeply committed. In accordance with established laws, discrimination based on race, color, religion, national origin, gender, age, disability, or veteran’s status is prohibited for employees in all aspects of employment and for students in academic programs and activities. Utah State University is dedicated to providing a healthy equal opportunity climate and an environment free from discrimination and harassment.


Utah Science Volume 61

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Number 2

Winter 2002

TURNING UP THE HEAT ON FIRE BLIGHT By Lynnette Harris A promising new way to battle a very old disease.

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TAKING THE BITE OUT OF BEETLES By Dennis Hinkamp Wasps win the battle of the wheat fields in a real life version of “Alien.”

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FIELDS OF DREAMS By Dennis Hinkamp Lush, green, rolling pastures are the stuff of dreams for cows and humans. Proper pasture management can make it the best for both worlds.

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UTAH SCIENCE is a publication devoted primarily to Experiment Station research in agriculture and related areas. Published by the Utah Agricultural Experiment Station, Utah State University, Logan, Utah 84322-4845. Lynnette Harris, Editor, lynnette@media.usu.edu Dennis Hinkamp, Research Writer, dennish@ext.usu.edu

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-new people, grants and contracts in science

SYNTHESIS -science at Utah State SEEK

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-students in science

-science on the web By Lynnette Harris

Mary Donahue, Graphic Artist, mdonahue@cc.usu.edu Gary Neuenswander, Media Specialist, gary@agx.usu.edu Michael Smith, Webmaster, mwsmith@agx.usu.edu

ON THE COVER: Blighted apple blossom with the sign of fire blight—amber bacterial ooze.

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Turning up

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Fire blight has the dubious distinction Apple orchard heavily infected with fire blight following a hail storm.

Sherm Thomson

of being the first bacterial plant disease described in North America. That was in the late 1700s, yet scientists continue to study the disease and how to fight it. USU plant pathologist Sherm Thomson’s guess is that there are more scientific publications about fire blight than any other plant disease. Coming from Thomson that’s a well-educated guess because he has studied fire blight for more than 30 years. The bacteria Erwinia amylovora causes the disease and can infect the tissues of a number of ornamental plants such as mountain ash, hawthorn and Pyracantha, for example. But the bacteria causes the greatest economic damage in apples and pears because blighted blossoms mean little or no fruit production and the bacteria can

the Heat on Fire Blight inflict fatal damage in a matter of days. Worst of all, in spite of the fact that scientists have known about E. amylovora for more than 200 years, there is still no treatment for the disease aside from cutting out infected tissue. And while an antibiotic, Streptomycin, is moderately successful at preventing fire blight, it must be applied preventively, well before any sign of the disease appears. Winter 2002

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Most fire blight outbreaks in fruit trees occur in May or June. The bacteria first infect the blossoms and may stop there. However, fire blight can quickly become systemic in trees. Thomson said many uncontrolled variables—the tree’s general health, precipitation levels and temperature—may determine whether an infected tree survives or dies and whether the bacteria will be isolated or spread to other trees. The disease gets its name from the charred appearance of blighted blossoms. “It looks like someone took a blowtorch to the flowers or leaves,” Thomson said. “They turn black on the edges within a few days and then the disease may spread rapidly into the shoots, limbs or the trunk. It produces a sunken, brown canker and amber colored ooze. It is a very rapid blight. Once the blossoms appear blighted it can become systemic and seriously damage the tree within a week.” The bacteria may not spread once the blossoms are infected, but not treating the tree is a risky gamble with entire orchards at stake. When the first signs of fire blight are visible it’s already too late to apply Streptomycin. The antibiotic can help prevent bacteria from infecting a tree, but cannot cure the disease once it is present. During bloom most growers choose to use the antibiotic to prevent flower infections but they are also aware of the expense of chemicals, the labor required to apply the bactericides and the less-easily calculated cost of introducing antibiotics into the environment and increasing the likelihood that the bacteria will become resistant to the bactericide. In fact, Thomson said, E. amylovora has become resistant to Streptomycin in most fruit producing regions of the United States. The bacteria can spread at an alarming rate through an orchard as insects visit infected blossoms and then carry the bacteria to other trees. In a typical Jonathan apple orchard, Thomson found that the incidence of flower colonization by E. amylovora increases from about five percent to nearly 100 percent of the flowers in the space of just two warm, dry days. Rain and hail are also very efficient at spreading the bacteria. In fact, a hailstorm is the worst thing that can happen to a fire blight-infected orchard because the hail damages leaves allowing the bacteria to rapidly enter and infect scores of places on the trees. 4

Utah Science

“Once you see the blighted blossoms you are never sure it will stop there,” Thomson said. “You are afraid to do nothing because you don’t know how far the infections will spread and the entire tree could be killed. Consequently, growers are very aggressive in cutting out infected tissues to prevent the spread of the disease. The recommendation for pruning is to cut one-to-two feet beyond areas with obvious symptoms. If you have a small tree and several infections you can easily see that you won’t have much of a tree left after pruning. Many trees can have more than one hundred infection strikes. When you’re faced with that situation you just stand back and say, ‘What do I do now?’” Thomson may have an answer to that question, based on several seasons of research in Experiment Station orchards

and commercial orchards throughout the state. He has developed a technique called solarization which involves using the sun, plastic and some ingenuity to heat trees and kill the bacteria that causes fire blight, stopping its spread and preserving the life of the tree. Based on observations that fire blight progresses much more slowly during


Sherm Thomson

Sherm Thomson, Utah State University Extension plant pathology specialist, with an apple tree under solarization tent.

Based on observations that fire blight progresses much more slowly during hot midsummer days, Thomson investigated the effects of high heat on the bacteria and on fruit trees. Apple orchard showing brown shoots killed by fire blight.

Sherm Thomson

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hot midsummer days, Thomson investigated the effects of high heat on the bacteria and on fruit trees. “There is a narrow range where bacteria can be killed between 112 and 115 degrees Fahrenheit (44 to 46C), but those temperatures must be maintained for two or three days,” Thomson said. “And you must keep the temperature below 120 (48.9C) degrees or you kill the tree,” Solarization essentially involves building a temporary plastic greenhouse around infected trees to raise the temperature inside to the 112 to 115 degree range; high enough to kill the bacteria but not high enough to damage the tree. Through a variety of experiments, Thomson has found that can be accomplished by covering trees with a fairly heavy (4 to 6 ml) sheet of clear polyethylene even during the moderately warm spring days typical in northern Utah. Thinner sheets of plastic will work but are difficult to use without tearing. Ideally, thermometers should be placed at the bottom, middle and top of the tree and monitored during the hottest part of the day to insure that trees are not being “cooked.” When temperatures under the plastic begin to get too high, simply loosening the plastic allows in enough cool air to drop the temperature very quickly. In one experiment, Thomson covered four Bartlett pear trees — each with about 50 fire blight strikes — with plastic from May 24 to June 1. High ambient temperatures on those days ranged from 75 to 80 degrees (24-27C) while temperatures under the tarps reached 118 to 123 degrees (48-51C). Cankers on untreated, infected trees in the orchard continued to expand for the next two weeks. But no bacteria were found alive in cankers on the solarized trees and the cankers that were already present did not expand after the treatment. Leaves in direct contact with the plastic usually burn and very high temperatures can damage young branches so care must be taken to keep trees from getting too hot. Thomson tells people to expect little or no fruit on trees during the year they have been solarized, but the prospect of saving trees without severe pruning is good compensation for the loss of one season’s produce. Many variables — temperature, age and condition of the trees — that make it difficult to prescribe one standard method of solarizing, but in many cases it’s a choice 6

Utah Science

between trying the plastic or losing the infected tree. And the time required to wrap a tree and even monitor temperatures under the tarp is less than the time it takes to prune 50 or more strikes from a tree, Thomson added. Thomson continues to plan and conduct solarization experiments, adding what he learns to the volumes that have been written about fire blight. This promising method of treatment may not be practical in all cases but it provides an alternative to pruning a tree to the ground. And, who knows, maybe pruners will be replaced by rolls of plastic in fruit growers’ collection of tools to fight fire blight.

Fire Blight and Apple varieties Most resistant to fire blight

Moderately resistant to fire blight

Delicious Liberty Priam Prima Priscilla Redfree Splendor Winesap

Golden Delicious Granny Smith Gravenstein Jonamac McIntosh Mutsu Spartan Stayman

Contact Info: Sherm Thomson Extension Plant Pathology Specialist Biology Dept. (435) 797-3406 shermt@ext.usu.edu


Some varieties of fruit are more Resistant to fire blight than are others. So why don’t fruit growers simply avoid problems by planting only the most resistant varieties? It’s a simple question of supply and demand. If you want to make a profit you have to grow what consumers want to buy, and at the grocery store most of us are bypassing the highly resistant varieties and plunking our money down for newer ones that are far more susceptible to fire blight. “Choices of varieties are ultimately consumer driven,” said USU plant pathologist Sherm Thomson. “People

Fire Blight and Apple varieties LEAST RESISTANT to fire blight Braeburn Cortland Fuji Gala Honeycrisp Idared

Jonagold Jonathan Rome Beauty Winter Banana Yellow Transparent

don’t want Red Delicious apples, which are highly resistant, they want Fuji, Gala and Braeburn. Name nearly every new apple variety and they are all highly susceptible to fire blight. It seems each new one that comes out is more susceptible. If these trees get an infection it’s much more likely it will kill the tree than it is if the bacteria attack a Red Delicious.” At left, is a list of apple varieties ranked for relative fire blight resistance. It is not a complete list of varieties and includes just some of the more commonly grown apples.

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Taking the Bite Out of Beetles Gary Neuenswander

Jay Karren, Utah State University Extension entomologist in action, examines leaves in the lab.

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How they got here is a mystery, but the damage they do is undeniable. Cereal leaf beetles can eat the profits out of most grain harvests. They had already been identified and contained in the eastern United States by the time they suddenly showed up in Utah in 1984. They had, in fact, never been seen anywhere west of the Mississippi before then. How they jumped several other states and ended up in a wheat field in north central Utah’s Morgan County is better left to detectives than entomologists. They may have hitchhiked on the straw carried by rodeo participants from others states or hoboed on cattle train cars that often pass through this area of the state. Though he likes a good mystery, Jay B. Karren, Utah State University Extension entomologist’s main concern is saving grain crops from this vagabond pest. Yield losses can be as high as 55 percent for spring wheat and up to 75 percent for oats and barley. Of course growers can always spray pesticides to contain the beetles, but it is expensive and eliminates chances of selling the grain as organic. There is also the economic threat of having your wheat quarantined from California markets if it isn’t certified cereal leaf beetle free. “Most northern Utah counties have been quarantined already and we want to protect other counties,” Karren says. “Fortunately, alternative methods such as using predator wasps had already proven effective in eastern states. Unfortunately, the process had become so effective that the predator wasps Winter 2002

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Cereal leaf beetle in Utah Yellow dots indicate no cereal leaf beetle found. Red dots indicate where cereal leaf beetle was found in summer, 2001.

Utah Science

USDA/APHIS

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It takes a little faith, backed by lab work, to convince grain growers that this biological control is working, Karren explains. . . We need to get the growers to agree to give the biological control a chance to work. It takes about three years for the wasps to fully establish themselves.


USDA/APHIS

were no longer easily available. Using a biological control such as the wasps can reduce yield losses to one percent and save $8-10 per acre in spraying costs.” Similar to other invasive species, the cereal leaf beetle is not a serious threat to crops in its native region –– the Mediterranean area of Europe –– because there are natural predators to keep it in check. In the 1960s USDA researchers went there and brought back several varieties of wasps to use as a biological control against the beetles. After extensive testing to make sure the wasps didn’t attack any crops or beneficial insects once they had done their work on the beetles, APHIS started propagating the wasps in its lab in Michigan. The program was such a success that the Michigan lab had stopped raising the wasps until cereal leaf beetles started showing up in Utah and three other western states. The wasps don’t eat the beetles directly, but attack the eggs or larvae in sort of a real life version of the “Alien” movies minus the scary music and Sigourney Weaver’s heroics. In the agricultural version, these aliens always win. One type of wasp lays its eggs inside the beetle larvae and another type lays its eggs in the beetle eggs. In either case, as the beetles hatch and grow, the wasp larvae eat through the beetle larvae killing them in the process. The wasps continue to propagate until the beetle population diminishes. It takes a little faith, backed by lab work, to convince grain growers that this biological control is working, Karren explains. After all, the growers can’t see the process going on and Top, the Tetrasticus julis wasp lays its eggs in a cereal leaf beetle larva. This wasp produces two generations a year, attacking the beetle population twice. It has been more successful in the western United States than Lemophagus curtus.

Bottom, Lemophagus curtus wasp laying its eggs in a beetle larva. This species performs best in the eastern United States.

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Left, a cereal leaf beetle in action.

Jay Karren

Above, a microscopic view of the crescent shape wasp larvae inside the beetle larvae. If 40% of the beetle larvae are “parasitized,� the crops are safe from any significant leaf beetle damage.

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Jay Karren

Right, a cereal leaf beetle in larval stage.


Jay Karren

The tellatale sign of cereal leaf beetle activity on leaves.

spraying is viewed as a sure thing. The problem is that spraying the field with pesticides will not only kill the beetles but the wasps as well. We need to get the growers to agree to give the biological control a chance to work. It takes about three years for the wasps to fully establish themselves. “June is the critical month when we start sampling,” he says. “To check the wasps’ progress we take leaf samples from the field and sort out the beetle larvae. We put them under a microscope and look for the wasp larvae inside. It looks like a tiny orange crescent inside the yellowish beetle larvae. If our sampling methods are accurate, we can deduce that if 40 percent of the larvae are ‘parasitized,’ then the crops are safe from any significant leaf beetle damage.” So far it has been a great success. Last year Cache County growers saved about $200,000 on grain that would otherwise have had to be sprayed. Utah growers have done such a good job of propagating the wasps that Karren regularly collects and ships them to Montana, Wyoming, Washington, Oregon and Idaho. His next goal is to expand the project to other counties. With an expected grant from APHIS, Karren hopes to expand the program to Utah, Davis and Weber counties.

Contact Info: Jay Karren Assistant Professor Biology Dept. Extension Entomology Specialist (435) 797-2514 jayk@biology.usu.edu

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Jeanette Norton studies soil nitrogen availability and its effect on rangeland grass establishment with funding from the USDA. The Utah Centers of Excellence program supports work on rapid bacterial testing for food and environmental samples at the USU Center for Microbe Detection and Physiology under the direction of Bart Weimer. In addition, Weimer investigates sulfur metabolism in Brevibacteria with funding from Kraft Foods. Associations between nutrition, endometriosis and incidence of disease near the time of calving in dairy cows is the subject of research being conducted by Douglas Hammon with support from Pharmacia Animal Health. Kenneth White studies cloning cattle from adult somatic cells with support from XY Genetics, Inc. Tilak Dhiman’s study of the influence of fat and fatty acid sources on the feed intake of dairy heifers is supported by Bioproducts. Dhiman also investigates the response of prepartum and early lactation cows to yeast cultures in their diet with funding from Diamond V Mills. Economist DeeVon Bailey receives USDA support for his study of the possible negative and positive effects on the market for red meat in the United States if proposed measures to track meat from producer to consumer are implemented. Roger Kjelgren’s analysis of urban landscape water demand is funded by the U.S. Department of Interior.

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Ron Munger studies relationships between genetics, nutrition and the incidence of facial anomalies such as cleft palate with funding from the National Institutes of Health. His related international collaborative research efforts are supported by the World Health Organization. Use of mammary ultrasound to aid in prediction of future milk producing capability of weaning and yearling beef heifers is the subject of research conducted by Randy Weidmeier with support from the Utah Department of Agriculture and Food. Plant-herbivore interactions are the subject of a shortcourse developed by Fred Provenza with funding from the USDA. Ted Evans studies insects as biological control agents for noxious weeds such as Squarrose knapweed, Canada Thistle and whitetop with support from the U.S. Department of Interior. The Utah Division of Wildlife Resources funds rehabilitation of the ponds at the Utah Botanical Center. Esmaiel Malek and Lynn Dudley study the use of saline waste water from electrical power plants for irrigation. Their research is supported by Pacificorp. Orbital Technology supports Bruce Bugbee’s development of plant bioassays. Integrated tools for livestock development and rangeland conservation in Central Asia are the subject of studies conducted by Nicanor Saliendra in cooperation with researchers at the University of California-Davis. Robert Sidwell directs studies of animal models of human viral infections to evaluate experimental therapies for influenza and orthopox viruses with support from the National Institutes of Health. Identifying characteristics of grass varieties for use in the Intermountain West is the subject of work done by Paul Johnson as part of the National Turfgrass Evaluation Program, a cooperative effort of the National Turfgrass Federation and USDA. Janis Boettinger works on the Logan Ranger District’s Soil Resource Inventory with funding from USDA. ○ ○ ○ ○ ○ ○ ○ ○ ○

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New Faculty & Staff

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Gary Neuenswander

joins the Animal, Dairy and Veterinary Sciences (ADVS) Department as a research associate professor and Extension poultry specialist. Bagley is based in Ephraim at the UAES turkey research facility. He was most recently technical services director for Tar Heel Turkey Hatchery in Raeford, NC, a facility that produces approximately 15 million poults per year. Prior to that Bagley was director of research and development at Hybrid Turkeys, Inc., Kitchner, Ontario, one of three primary breeding facilities in the world. He received an AS degree at Snow College, a BS at Utah State and an MS at Brigham Young University, all in animal science. He earned his PhD in physiology and poultry science at North Carolina State University.

Thomas Baldwin joins the ADVS Department as associate

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Gary Neuenswander

professor and director of the Utah Veterinary Diagnostic Laboratory. He received his BS and DVM degrees at Washington State University (WSU), his PhD at Louisiana State University. Prior to his new appointment, Baldwin was assistant professor in the Department of Veterinary Microbiology and Pathology at WSU where he was involved in research, teaching and service in the department and the Washington Animal Disease Diagnostic Laboratory. He has been named a diplomate of the American College of Veterinary Pathologists.

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Sam Daines is the first director of development for the Utah

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Gary Neuenswander

Botanical Center. While still in his teens, Daines traveled the globe with his father as he consulted on agricultural development projects designed to feed people and help them prosper financially. Those experiences and his subsequent bachelor’s degree in zoology from BYU, master’s degree in biology from Cambridge, certification in non-profit management from George Mason University, and more than 10 years experience in development and marketing organizations that are committed to ecological preservation make him a valuable new asset to the UBC team.

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High school science goes biotech

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udging from conversations among the Utah high school students and teachers participating in the inaugural sessions of two new biotechnology workshops at USU, one could easily conclude that high school science classes aren’t what were they used to be.

Twenty-two students were accepted for the first USU Biotechnology Summer Academy, a week of laboratory training, discussions of ethical issues related to biotechnology, working individually with faculty researchers and evenings devoted to fun. Faculty in biology, chemistry, engineering and food, animal and plant science volunteered to mentor the students during the week, giving them hands-on experiences in biotechnology research.

Bingham High School student Sharon Davis agreed, saying her week in biological engineering professor Tim Taylor’s lab was like an internship. She added that it was a little nerve wracking to learn that a three ounce vial of purified protein she was holding would be worth more than a million dollars in the biotech industry. “You’d never get to do this kind of stuff in high school,” Davis said. But students in Utah schools may be exposed to more biotechnology techniques and concepts as teachers who attended the seminar for high school science teachers add what they learned to the curriculum. Scott Snelson from Murray High School told fellow teachers about the outstanding biotechnology program he has helped build at his school, shared some important “how to...” information and topped off the presentation with photographs of

his students in lab coats and safety glasses analyzing DNA. “It’s not just the science geeks in our biotech classes,” Snelson said. “It’s important for students to understand biotechnology so our classes are not just AP (advanced placement) courses. I’ve got some of every kind of student in those classes.” With curriculum that includes performing gel electrophoresis, extracting and studying DNA, and discussing the ethics of inserting genes from one organism into another, it’s safe to say this is not your father’s science class. It’s not even the science class of anyone who bid farewell to high school more than five years ago.

Mandy Smart

“Biotechnology is the technology of the twenty-first century,” said Kamal Rashid, acting executive director of USU’s Biotechnology Center. “We want to help teachers better understand the importance of biotechnology and the methods they can use to teach it in their classrooms. We are also committed to doing outreach to students who will become tomorrow’s scientists and the highly trained workforce that will help attract more biotechnology companies to Utah.”

“I didn’t expect to be working on real research projects and doing real work in the lab,” Morgan High School student Clark Sessions said of his week in Noelle Cockett’s lab, where he helped uncover information about animal genetics. “It’s great. I’m learning a lot and you can have educated conversations with people about what you’re doing.”

Top: Misty Baggerly,from North Sanpete High School,is putting DNA into a gel for a gel electrophoresis experiment. Bottom: Sharon Davis,from Bingham High School, and Jacob Layton,from Clearfield High School, are pipetting solutions.

Rasmussen appointed associate VP for research

U

“Moving back as associate vice president for research will be a welcome challenge,” Rasmussen said. “There are many outstanding research faculty and programs at Utah State and I look forward to the opportunity to work more closely with them.” Rasmussen earned a B.S. in botany and plant pathology from Utah State. He received an M.S. and Ph.D. in horticulture from Michigan State University. He formerly chaired the national Experiment Station Council on Organization and Policy.

Gary Neuenswander

tah State University President Kermit Hall has appointed UAES Director Paul Rasmussen the university’s associate vice president for research. Rasmussen will continue in his role as Experiment Station director, a position he has held since 1989. Many responsibilities accompanying the new position will not be new territory for Rasmussen, who served as associate vice president from 1992-1999.

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Sci Synthesis USU professor discovers symbiotic bacteria

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s insect species have evolved, some have developed symbiotic relationships with bacteria that have lasted over millions of years. But USU entomologist Carol von Dohlen, Electron Microscopy Laboratory supervisor William McManus and undergraduate researchers Shawn Kohler and Skylar Alsop have documented what is believed to be the first example of intracellular symbiosis involving two species of bacteria. The team published its findings in the journal Nature, describing bacteria living inside bacteria of a different species living inside specialized cells of mealybugs— essentially bugs, in bugs, in bugs. The researchers’ work focused on mealybugs, close cousins of aphids, which feed on sweet plant sap. Scientists have been aware that such insects hosted bacteria since the early 1900s. “The sap is high in sugar, but low in protein,” von Dohlen explained. “The bacteria in aphids produce amino acids— protein the insects need for survival.” The team knew that mealybugs hosted two species of bacteria, beta-Proteobacteria and gammaProteobacteria, and that at least some of the bacteria were packaged in “...symbiotic spheres— some sort of vesicle— of unknown origin.” She assumed the beta- and gammaProteobacteria lived side-by-side or in separate cells. To test this idea, the team designed fluorescent molecular probes to specifically match certain molecules in the two kinds of bacteria. When they used a laser-

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scanning confocal microscope to examine thin sections of mealybugs on which the probes had been applied, they saw very clear signals from the gammaProteobacteria inside spheres, but the beta probe also detected bacteria in the same spheres. “We thought, ‘This can’t be.’ We knew from our electron microscopy work that there was no second form of bacteria in the spheres,” von Dohlen said. “We were tearing our hair out and Bill (McManus) suggested that the spheres themselves might be beta-Proteobacteria.” The team considered McManus’ suggestion, examined the data again, and it suddenly all made sense. Further examination confirmed that the gammas do live inside the betas. “Sometimes an answer is staring you right in the face, but you don’t see it because you’re blinded by a preconceived notion,” von Dohlen said. “Sometimes you have to just trust the data and listen to fresh viewpoints.” Just what the gammas’ function is isn’t known, but the researchers speculate that the betas may be using gene products from, or even exchanging genetic material with, the gammas to compensate for genetic defects in the betas accumulated over millions of years of intracellular existence. Carol Von Dohlen . . . Assistant Professor, Biology Department (435) 797-2549 cvond@biology.usu.edu

An electron micrograph of a mealybug host cell containing bacteria. Green highlights the nucleus of the insect's cell, gray is the insect cytoplasm, blue highlights the beta bacterium and red indicates the gamma bacteria living inside the beta bacterium.


ence Synthesis New hard white winter wheat variety

“

Golden Spike� is the first hard white winter wheat released in Utah and one of the first winter hard white wheats released anywhere in the United States.

Gary Neuenswander

Developed by Experiment Station researcher David Hole, the new variety has excellent baking qualities as well as good noodle qualities make it one of a few dual purpose wheats available to growers. General Mills is impressed with the quality and yield abilities of the variety and has negotiated an exclusive license for its production outside of Utah. Within Utah, it will be treated as a Plant Variety Protection cultivar and is available only from licensed dealers. A contract negotiated

with General Mills requires Utah growers to sign an agreement stating they will grow Golden Spike only on property in Utah. It has superior snow mold resistance as well as resistance to dwarf smut, and some race specific resistance to stripe rust. Golden Spike has low polyphenol oxidase (w) activity which is one reason it is desirable for Asian noodles. PPO causes browning and discoloration. In addition to Golden Spike, other hard red winter lines (such as UT2030-32) are under consideration for release. David Hole . . . Associate Professor Plants, Soils, & Biometerology Dept. (435) 797-2235 dhole@mendel.usu.edu

D

ani Or received the Don and Betty Kirkham Soil Physics Award from the Soil Science Society of America. The award honors mid-career soil scientists who have made outstanding contributions in soil physics. Recipients are recognized for their originality in applied research and their excellence in undergraduate teaching.

of his dedication as a teacher and for his research that has furthered the understanding of fundamental processes that affect liquid behavior in different types of soil. He has also advanced the field of soil science by creating bridges between soil science and related sciences.

Gary Neuenswander

Electron Micrograph by William McManus, false colorization by Heather Leary, Electron Microscope Facility, Dept. of Biology, USU

Dani Or wins soil physics award

The award is funded by the Agronomic Science Foundation.

According to David Kral, associate executive vice president of the Soil Science Society of America, Or was selected because Winter 2002

19


F i e l d s 20

Utah Science

of


P

astures are part of our heritage and mind set. When you think of farming the image that most likely pops into your head is one of scattered groups of cows or sheep on gently rolling pasture. The word “pastoral” is defined as “an idyllic setting.” Like most things idyllic, this image is only true part of the time. Especially in the West, animals may graze on open rangeland where there is little grass or they may spend most of their lives in confined drylot systems where all their feed and water is closely regulated. Pasture grazing has also fallen out of favor as dairy herds have grown and dairy cow productivity has increased. Pasture grazing shouldn’t be relegated to nostalgia. It is, in fact, making a comeback. Free-range chickens and grass-fed beef are starting to show up in supermarkets and restaurants as a reaction to the unsavory image of large-scale, or factory, farming. Still, these products represent only a small sliver of the meat and poultry market. In truth, these products are often just products of marketing. Most beef cattle are raised on grass for the majority of their lives, and are just “finished” with grain before they go to market, explains Jennifer MacAdam, Experiment Station researcher in the department of Plants, Soils and Biometeorology. Beef cattle get about 80 percent of their total lifetime nutrients from grass and forages. Even dairy cattle that are not on pasture are fed primarily a diet of the same grasses and legumes that would be available on pasture. The only difference is that the grasses are harvested for them.

D r e a m s Winter 2002

21


publication was based on his observations that if you move animals from one section of a pasture to another every 3-5 days, it gives the grasses a chance to rest and regrow. The concept seems fairly intuitive, but has only caught on after plenty of time and research. Grazing animals, like most humans left to their own devices, will eat the tastiest available food first. However, if you follow that pattern too long, soon the only thing left to eat in the house or on the pasture is the least tasty food. While humans can go out and buy more chips, livestock just keep eating the best for-

Gary Neuenswander

There is more to grazing than aesthetics and marketing. It can be more profitable for farmers, healthier for the animals and better for the environment. Small dairy operations of 200 cows or less are especially well suited for grazing. Operations this size can do without much of the machinery and chemical inputs that large-scale operations use to keep a competitive advantage. If managed properly, the pastures provide the feed and the cows harvest and fertilize the pasture. “In most cases the productivity of each cow may go down a little, but the profitability of each cow goes up,” MacAdam says. “Pasturefed cows generally have fewer health problems and have a longer productive life for the dairy producer.” One of the sometimes overlooked benefits is the reduced impact on the surrounding environment, she says. There are fewer chemical fertilizers used that can run off into streams and groundwater. It also increases the value of the adjacent land because pasture-based dairy operations tend to have fewer problems with flies and odor that lead to disputes between farms and nearby residential areas. In fact, livestock production on irrigated pastures, whether beef or dairy cattle or sheep does come pretty close to the idyllic pastoral image most people have. Intensive rotation, as opposed to continuous grazing, makes the greatest use of pasture resources by grazing animals. This grazing method can be traced to the 1959 publication “Grass Productivity” by Andre Voisin, a French biochemist and cattle producer. The

Susan Buffler

Gary Neuenswander

Jennifer MacAdam researches ways to make intensive rotational grazing more suitable for Western irrigated pastures.

A bad pasture. . .

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Utah Science

Versus a good pasture. Jennifer MacAdam’s pasture research plots at the Caine Dairy in Cache Valley, Utah.


Susan Buffler

ages down to the roots and eventually there is nothing left in the pasture except the least desirable plant species. Animal gains per acre are higher under rotational than continuous grazing, because much less plant biomass goes to waste. MacAdam says intensive rotational grazing has been widely used for sheep and dairy production in New Zealand and the United Kingdom for decades, but it is only used on about 10 percent of the dairy farms in the northeast United States because there hasn’t been reliable information available for regional

A close look at the promising legume, birdsfoot trefoil.

climate, soils, management practices and forage quality. In 1995, her research at the Evans Farm began to address the specifics of types of grasses and legumes best suited for forages in Western irrigated pastures. The first stage of the project was to identify the best grasses and legumes for this climate, she says. Unfortunately, most native grass species are not as well adapted to livestock use as those commonly grown under irrigation. Cattle coevolved eating the types of introduced grasses that need irrigation in western pastures. “For instance, the growth patterns of perennial ryegrasses are well understood in countries such as Ireland and New Zealand, but in the western U.S. we are dealing with a unique set of stresses in a cold, semi-arid environment. Even with irrigation, we would like to find or develop types with a high degree of drought tolerance.” It’s a difficult equation, she adds. “In this climate clover is a good addition to ruminants’ diets to meet protein needs, but it tends to take over the pasture. In addition, consuming too much clover can lead to bloat in grazing animals. There are other promising legumes we are testing such as birdsfoot trefoil, which is highly productive but non-bloating.” Intensive rotational grazing is not an either/ or proposition. Producers will likely use some economical combination of pasture and grain or harvested forage to best meet livestock nutritional needs. “The next step of this research project is to measure the productivity of cattle grazing on various grass and legume combinations,” MacAdam says. “We are just starting to analyze the first year’s data from cattle studies at the Caine Dairy Center.”

Susan Buffler

Contact Info: Jennifer MacAdam Associate Professor Plants, Soils, & Biometeorology Dept. (435) 797-2364 jenmac@cc.usu.edu

A happy cow at the research pasture.

Winter 2002

23


seek

-students in science

Gary Neuenswander

t

odd Miller’s father has been known to tell people that his son is trying to find ways to turn manure into gold. Miller doesn’t spend his days studying alchemy, but he is part of a team of undergraduate researchers studying methods of handling animal waste that reduce odor and potential pollution while producing harnessable energy and animal feed. That goal may seem as likely as turning manure into gold, but the project’s initial success is garnering interest from animal and dairy producers as well as fueling the students’ dedication to the research. The system Miller helped develop involves anaerobic and aerobic digestion in a series of ponds. A working, two-cow model of the process was built after a mathematical formula helped Miller and his colleagues determine the structural requirements for a small-scale system. First, thick wastewater collected from the Experiment Station’s Caine Dairy Research and Teaching Center is pumped into the bottom of an underground anaerobic pit where the solids are broken down by bacteria. Next, the wastewater undergoes more clean-up as other bacteria work on it in an aerobic pond that sits above the anaerobic pit. From there, it moves through a series of pools where various plants remove nutrients from the water. What emerges are an odorless, clear liquid suitable for use in irrigation; plants such as duckweed and Spirulina algae to supplement livestock diets or support production of fish and other aquatic species; and biogas, a natural gas created by the process that is collected and could be burned to generate electricity or heat. The student researchers, working with assistant professor of Agricultural Systems Technology and Education John Harrison, are refining their models, but currently estimate that the volume of animal waste that must be managed at confined feeding lots (dairy, poultry and swine) in Utah each year could provide enough biogas to power 67 million homes. 24

Utah Science

“Our goal is to create a system that lets producers view waste as an asset instead of a problem,” Miller said. “Some parts of this system are used in other places so we’re not necessarily creating something entirely new, but gathering all the parts and using the technology in this way is a revolutionary thing.” The system they have devised— officially known as an integrated facultative pond (IFP) system—greatly reduces odor problems, an increasingly important factor as neighborhoods are built closer and closer to agricultural areas and the new neighbors usually want the atmosphere of the “country” but without the smells. Miller said some members of the student research team are investigating which fast-growing water plants remove the most nutrients from the wastewater while providing the high protein content needed to replace supplements such as soy in animal feed. Others on the team are looking at ways to automate the system so producers don’t have to tend it every day. Treating animal waste and creating a natural gas resource seem like a bit of a stretch for someone who is headed for medical school, but Miller doesn’t find his research and career aspirations to be an odd mix. “I come from an agriculture background and this project is about applied science.” Miller said. “Doing research teaches you things you would never be able to learn in a classroom. Medical schools require you to have done research as an undergraduate and nearly every student on this project is a pre-health professional and in the Microbiology Club. All of us working on different aspects of the project makes the whole system better.” Miller said his work on the waste management is not his first research experience as an undergraduate. He is a nutrition major and formerly worked on a project aimed at adding flavorings to cheese. “That was an interesting project,” he said. “When I was involved in that research, my dad told people I was a professional cheese taster.”

“Doing research teaches you things you would never be able to learn in a classroom.”


search

-science on the web

Find Utah Science and other information about the people and projects of the Utah Agricultural Experiment Station online at www.agx.usu.edu

Fire blight Extention.usu.edu/plantpath/index.htm Resources to help you diagnose plant diseases in grains, fruit, ornamental plants, turf and vegetables. Includes instructions for submitting plant samples to USU Extension for diagnosis.

The researchers featured in this issue recommend the following Web sites for more information on their research topics.

Cereal leaf beetle scarab.msu.montana.edu/ipm/clb.html Descriptions of the cereal leaf beetle life cycle, where to find them and how to fight them. Pasture and grazing www.scas.cit.cornell.edu wwwscas.cit.cornell.edu/forage/pasture/ Although this guide was written in 1993 for dairy producers in New York, it covers the basics and is a solid resource www.cas.psu.edu/docs/CASDEPT/ AGRONOMY/Forage/docs/pastures/ 4steps.html Pennsylvania State University offers this guide for determining animal units and estimating acres of pasture, number of paddocks and paddock size. Wheat breeding wheat.usu.edu The USU Small Grains Research group’s Web site offers information on new cultivars and links to other online resources devoted to wheat, barley and other small grains. The UAES offers these recommendations as a service to readers, but is not responsible for the content of sites it does not produce.


Utah Science Vol 61 Number 2