Delicate Work

Growing Azaleas in Minnesota

The azalea's delicate-looking blooms appear as fragile harbingers of spring in Minnesota. But frail as they appear, the perennial azaleas developed by the U of M are obviously much tougher than their ubiquitous southern counterparts.

The release of Northern Lights in 1978 was the culmination of farsighted efforts: 28 years of crosses and tests to insure hardiness started by researchers Al Johnson and Leon Snyder. Plants differ greatly in their hardiness, or ability to grow and thrive in a given climate. Generally, the more southern the seed source, the less hardy the plant will be. And azaleas were southern, until then. "It was exciting for northern gardeners, and a noteworthy achievement for the University," says Harold Pellett, who has headed the Agricultural Experiment Station funded research since 1978.

Tri Lights azalea--a coming attraction

The success of Northern Lights as a fully hardy azalea led to other breakthrough adaptations. In 1984, two new releases, Pink Lights and Rosy Lights showed success in varying color. Since then eight other azaleas have been introduced, in colors from white to salmon to yellow, and with various desirable characteristics--"compact," "extremely floriferous," or "greater mildew resistance." "The first criterion was hardiness," said Pellett. "Once that was achieved, we started looking for other genetically determined qualities such as color range, plant foliage, disease resistance, and flower quality." The newest release, set for spring of 2003, is the first azalea to incorporate three colors, appropriately named Tri Lights.

"The development of new characteristics can happen faster now, because we know more about the parents," says Pellett. In the beginning there were very few people involved and there was limited knowledge about, for example, whether the plants would self-pollinate or not. Now, researchers have learned which techniques to use to make crosses, and can do more predictable manipulations.

That said, developing a new, reliable variety still takes years, because plants have to grow to maturity before crosses are made, and there are always surprises, both in the field and in labs. "The weather conditions that cause most home gardeners to worry and rush to add cover can be just what the research staff is waiting for," says Pellett. Typically, the plants are not protected in the field, the exception being a specific parent with valued characteristics.

Mandarin Lights azalea

"You do have to throw out a lot of plant materials-not only if there is a hard freeze that shows you which plants are most hardy, but in the greenhouse. We're looking for very specific characteristics: for improvements and variations in color or in quality of the bloom, for example, very slight differences can make a difference in what we choose to continue," he says.

Researchers work in labs equipped to freeze plant materials at levels down to -40°F. Stems and buds from various plants are monitored with a thermocouple, and then examined under microscopes to determine at what temperature damage occurs. Damage varies according to the time of year and how acclimated the plant is; plants can survive extreme cold at the peak of winter, but in late fall, an extreme cold snap causes great damage.

After nearly 25 years of working with azaleas and other woody ornamentals as varied as red maples, dogwood, and viburnum, Pellett is retiring from the U of M. He will continue his work as executive director of the Landscape Plant Development Center, a national organization housed at the Minnesota Landscape Aboretum. An Iowa native, who grew up in a market gardening family and often harvested two acres of vegetables before school, Pellett says he may even find time for work on his own yard and garden. And he won't stop thinking about new types of azaleas: red azalea--azaleas that bloom later in summer, azaleas resistant to mildew.

--Arlene West

Harold Pellett is in the Department of Horticultural Science in the College of Agricultural, Food, and Environmental Sciences.

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Managing Messy Neighbors

Curbing Canada Goose Populations in Urban Areas

The numerous lakes and wetlands of the Twin Cities-many bordered by parks, golf courses, and athletic fields-create an ideal habitat for Canada Geese. So ideal, that James Cooper, who has studied geese since the late '60s, calculates that the area could support 1.5 million honkers.

Currently there are fewer than 25,000 Canada Geese in the metro area. But without controls that began in the early '80s, there would be at least ten times that many according to Cooper, the country's leading expert on urban geese. A case in point is southern Ontario, which like the Twin Cities had about 500 geese in the '60s and now has more than 350,000.

Finding an appropriate balance of geese in urban areas is a problem. "If we didn't manage them, people would view them as pests," says Cooper. "I hope that by keeping goose numbers reasonably low through effective management, people can see them as a valuable and attractive resource rather than like sparrows or rats."

During fall migration, the metro goose population almost triples. They congregate in farm fields, athletic fields, golf courses, and airports, where they are not only a messy nuisance, but dangerous. According to Cooper, an average goose is so large it can destroy a jet engine and cause serious damage if it hits the fuselage.

Transmitters placed on geese show that they return to the same fields every fall. Since 1984, researchers have banded geese within 10 miles of the Minneapolis-St. Paul airport to identify and remove nuisance birds. Today, the likelihood of a commercial jet colliding with a goose has been reduced by 90%, and it is estimated that goose management saves more than $1 million a year in reduced aircraft repairs and down time.

Cooper's Experiment Station-sponsored research led to three strategies to manage goose populations, which are used by most cities with large numbers of the birds:

• Limit access. Fences keep geese off of shorelines during the summer flightless period, but can impact other shoreline animals like turtles. Herding animals, such as border collies, can keep geese away. Geese displaced by dogs or fences, however, just move to another site.
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• Limit nests. Kansas City and St. Louis tried a program to destroy eggs, but workers couldn't keep up. Those cities now have to remove 9,600 geese per year for the next 10 years, says Cooper. "Because population growth is exponential, the longer you fail to limit the population, the longer you will have to work to do so," says Cooper.
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• Limit the population. Goslings always return to the place where they learned to fly, so young goslings are sent to amenable rural locations in Minnesota and Iowa. Mature geese are processed and given to food shelves.

"Effective management uses programs that have a reasonable chance of working," says Cooper. "When they don't have respect for animals, people will use pellet guns, poison, run over them with golf carts-not the ethical treatment of wildlife we'd like to see."

--Arlene West

James Cooper is professor emeritus in the Department of Fisheries, Wildlife, and Conservation Biology in the College of Natural Resources. His work has been a collaborative effort of the University and the Wildlife Division of the Minnesota Department of Natural Resources for more than 20 years.

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Fungi Has Its Place

Prairie Diversity Depends on Interplay of Plants and Disease

Most of us see microorganisms that cause diseases in plants in a negative light. That's understandable, because diseases are usually noticed only when they threaten food, fiber, or ornamental plants. Black stem rust, which threatened wheat crops up until the '60s, and white pine blister rust, which kills trees, are notable examples.

But in natural ecosystems, plant diseases play a role in maintaining a more stable, resilient, and diverse community. "We shouldn't let what we see in agriculture influence how we treat natural ecosystems," says plant pathologist James Groth. Flare-ups of a disease in a diverse setting are never as bad as in a monoculture system, and fungi and other plant parasites are vital to native prairie diversity by preferentially curbing dominant plants that could take over and eliminate rarer species.

Plant pathologists study the effects of prairie fires on fungi, which in turn affect other prairie species such as Little Bluestem.

Groth and graduate student Charlie Barnes are engaged in a five-year research project at the University's Cedar Creek Natural History Area, north of the Twin Cities. Funded by the Agricultural Experiment Station, with the support of the National Science Foundation Long-Term Ecological Research Project, they are working to determine how fire and other preserve management techniques affect rust fungi. Rust fungi (rust colored plant parasites) are used in these studies because they occur on both native and agricultural plants in Minnesota, and because each of the many rust species is specific to a few plants.

Barnes monitors 78 plots and records the complicated life cycle of a rust fungus that, like many, needs two hosts. It moves from small flowering Camandra plants in the spring to Big Bluestem grass in the summer and fall. Spores typically travel 20 to 30 meters, but plots isolated by managed burns have shown that they will survive up to 100 meters. Still, if large prairie remnants are burned at one time, and the nearest unburned host plants are miles away in the next remnant, survival of the fungus is threatened.

"There is no reason whatsoever to eradicate native plant diseases," Barnes says. "You may be making room for another more aggressive plant or disease. Disease is valuable to diverse ecosystems, where lots and lots of different plants share the same place." The beauty of native prairie should not be underestimated, says Groth. Natural preserves provide a scenic contrast around intensively farmed areas. "Naturally occurring disease in plants is the norm, not the exception," says Groth. "Prairie preserves should not be managed to the extent that we eliminate fungi. Some disease fungi are conspicuous and unusual, and can be just as interesting to visitors as butterflies and flowers."

--Arlene West

James Groth is in the Department of Plant Pathology in the College of Agricultural, Food and Environmental Sciences.

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Parents in Grief

Living with the Loss of a Child

Of all the pains a parent can imagine, the death of a child is probably the worst. For most parents that nightmare never comes true, but for a few it comes and never goes away.

Questions of how parents grieve, and how they relate to each other during the process, is the focus of family life researcher Paul Rosenblatt's recent publication, Help Your Marriage Survive the Death of a Child. Meant for grieving couples to help them through the strain and stress, it is a compilation of interviews with 58 parents in 29 couples or former couples. His eighth book, it follows Parent Grief, a scholarly book published in 2000 for educators and therapists.

Rosenblatt's research relies on narrative interviews, lasting from one to three hours. "The people who were interviewed are experts on their own experiences, and there is enormous value in taking what they have to say seriously and understanding it in its own terms," he said.

When Rosenblatt distributed an ad through the University news service, he was surprised by hundreds of responses from people who had lost a child--some as recently as a few months to as long as 35 years before. "They come with a range of issues--some want to say they're fine, some have a religious message, or really want to talk about their families," he said. Although he would like more diversity, all 58 participants in the parent grief study are white. "We look for patterns in their narratives, for what issues come up repeatedly." Divorce is not as common as assumed--only two of the couples in the study are divorced, and both marriages were in trouble before the child's death. The tragedy brought most couples closer together.

Rosenblatt is now focusing on how African Americans may handle grief differently. "A history of having to deal with a racist world can change how you grieve," he said. "A lot of people talk about being strong, and I think it is much more the norm in that population." Family social science graduate student Beverly Wallace, a pastor and former hospital chaplain who is black, is conducting the interviews and collaborating on the writing.

Rosenblatt has studied grief and loss with support from the Agricultural Experiment Station for more than 30 years. He says in many ways he feels like a beginner every day. "I have always watched people, and have been curious and wanted to know more. I love interviewing, and I love teaching students those techniques," he said.

--Arlene West

Paul Rosenblatt is in the Department of Family Social Science in the College of Human Ecology.

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Flax Fights Cancer

Study Confirms Cancer Prevention

The cancer fighting benefits of an ancient seed--flax--are receiving new attention thanks to a study involving 32 postmenopausal nuns from the Order of St. Benedict near St. Cloud. The women added either 5, 10, or no grams of ground flax seeds to their daily diets. Nutrition professor Joanne Slavin and graduate students analyzed urine and blood samples to measure the impact on each subject during the 21-week study supported by the National Cancer Institute and the Agricultural Experiment Station.

The results demonstrated an increase in protective estrogen levels, which may prevent some hormonally related cancers, such as cancers of the breast and uterus. Flax is rich in lignans--chemicals that act like the female hormone estrogen in the human body. The phytoestrogen--"phyto" means "plant"--helps the body fight against disease by replacing protective estrogen.

Soy has similar qualities, says Slavin, but a little flax goes a long way. In the study, five grams a day (about a tablespoon) had a good impact, with 10 grams showing only slightly better results. For comparable effects, a greater amount of foods containing soy would have to be consumed.

As a registered dietician, Slavin is committed to helping people get phytochemicals through foods. "Ground flax is fairly easy to put into foods, especially breads and cereals. In the study, seeds were ground and then stored in the freezer because the meal oxidizes fairly quickly. The women put it on cereal or stirred it into yogurt. Since then, research has shown even when ground flax is baked into bread, the lignans are still viable," she said.

Flax is sold in several forms. Flax oil--the edible version developed at the U of M--provides one of the Omega-3 acids proven to prevent cancer. The seeds themselves have laxative properties, but are not as digestible as ground seeds. Slavin cautions against a trend toward isolating the phytoestrogens--both from soy and flax--and selling it in tablet form: "As a food, flax has fiber and phytochemicals. We're not sure what compound in flax gives it the health benefits, so for now it's best to eat flax as a food rather than as isolated lignans."

Although the tiny, purplish seeds were known to the Greeks and Romans as a healthy food, in modern times flax has been relegated to animal feed status. Slavin wants to promote the benefits of flax, and welcomes recent publicity in the Chicago Tribune and the Twin Cities' Star Tribune." We can add flax to our diets so easily, and because it is a safe food that has been consumed for years and years, there doesn't seem to be a down side," she says.

The nuns in the study agree. Many of them reported that they felt better and would continue adding flax to their diets.

--Arlene West

Joanne Slavin is in the Department of Food Science and Nutrition, College of Human Ecology. She worked with Amy Olson of the College of St. Benedict, and U of M graduate and undergraduate students.

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When Cows Bite the Dust

Simply Composting in Sawdust

A low-cost, single stage composting process to dispose of livestock carcasses could simplify the problems farmers face when animals die. Researchers are testing the effectiveness of simply burying cattle carcasses under piles of moist sawdust until they decompose. For many farmers, disposal methods now approved are either impractical, unavailable, or deemed too costly.

Although the process is taking longer than anticipated, researchers are optimistic about the potential for the technique. After all, says James Boedicker, agricultural engineer, "What's time to a dead cow?"

Disposing of dead livestock is a challenge in rural areas. Agricultural engineer Jim Boedicker uses a four-foot long thermometer to check the internal temperature of carcasses buried in sawdust.

At the North Central Research and Outreach Center's Beef and Forage Research Farm south of Grand Rapids, a test pile was formed in the fall of 1999 containing three 400- to 500-pound calf carcasses. Two more piles were formed in spring of 2000, each containing the carcass of a mature cow and that of one or two stillborn calves. Piles were formed by placing the carcasses on a 12- to 15-inch thick sawdust base and covering them with additional sawdust at least one foot thick.

Temperatures in the first pile reached 140° to 150° F. before declining, with the pile going dormant over winter. A second, less pronounced heating cycle occurred in the spring and summer of 2000, but by fall, bones were still hard. The other two piles produced internal temperatures similar to the first pile.

By fall of 2001, hard bones could still be felt in all piles. Also, pile interiors had dried considerably. Adding water to the piles is being considered this spring to accelerate bone breakdown. When decomposition is considered complete, each pile will be sampled for pathogen analysis.

Over time, incidents of animal intrusion into the piles-probably skunks, dogs, and foxes-have increased. Although a multi-strand electric fence around the piles has been considered, it is assumed most farmers would be unwilling to make that investment.

In addition to funding from the Agricultural Experiment Station, the project was initially sponsored by the MN Department of Agriculture.

--Arlene West

James Boedicker is a biosystems/agricultural engineer at the North Central Research and Outreach Center.

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Rapid Response Fund Targets Major Issues The Minnesota State Legislature provides special funding to address urgent issues challenging Minnesota. In addition to the ongoing research on Johne's disease reported on here, these University research projects received funding through the Rapid Agricultural Response Fund: Disease and Insect Resistant Potatoes Soil Pathogens in Irrigated Dry Beans Soybean Aphids Anthrax Patterns in Minnesota New Kentucky Bluegrass and Perennial Ryegrass Best Use of Drugs in Dairy Herds Early Warning Diagnostic System for Swine Alternative Swine Production Ssytems Microbial Safety of Organic Produce Potato Disease Prevention Restoring Native Legumes PRRS Virus in Swine Turkey Respiratory Disease Details of these projects will appear in Minnesota Science, or may be checked at http://www.rapidresponse.umn.edu. Facing a Century-old Disease Major Steps Toward Detection and Control of Johne's in Cows Several interrelated projects by the Minnesota Johne's Working Group (a multidisciplinary group of researchers and diagnosticians at the University of Minnesota, College of Veterinary Medicine, in collaboration with the Minnesota Board of Animal Health) are addressing the challenge of control of Johne's disease, supported by the Agricultural Experiment Station, Rapid Response funding from the state legislature, and USDA funding. Johne's disease (pronounced Yo-knees) has been known to afflict cattle since 1895. It disrupts nutrient absorption, leading to chronic weight loss and eventual death. There is no effective treatment for Johne's. Because current testing detects the agent only in later stages of the disease, after a cow is two to three years old-and most farmers purchase cattle to add to their herds each year-it has spread worldwide, according to veterinary epidemiologist Scott Wells. Kay Fasberg leads a team in the Minnesota Veterinary Diagnostic Laboratory developing a quicker Johne's detection test. The economic impact in Minnesota-the nation's fifth highest producing dairy state-is high, because Johne's disease reduces milk production and shortens the productive life of cattle. Minnesota's dairy industry generates over $1 billion each year in income from milk production. Beef production from dairy and beef cattle operations generates another $800 million. Annual economic losses associated with Johne's disease in heavily infected herds is estimated at over $200 per cow. While the scientific evidence for related disease in humans is not strong, concern has arisen that M. paratuberculosis, the bacteria causing Johne's disease, may be a cause of Crohn's disease in humans. Wells estimates more than half of Minnesota's dairy herds have infected cattle, many with over one-fourth of their cattle diseased. Typically, infected animals are removed from the herd as soon as signs of the disease appear, but due to ongoing expansion of dairy herds, the disease is spreading rapidly. "The bottom line is that it is a difficult disease to study," says Wells. "There is a two- to five-year incubation period from infection to disease onset." Research Goals Researchers are looking for earlier and faster ways to detect the disease. Genomics researcher Vivek Kapur is leading the team working to sequence the genome of M. paratuberculosis, key to both improved diagnostic tests and development of a vaccine. The group has already identified several unique DNA sequences that could lead to new tests. Improved diagnostic tests that rapidly detect the pathogen in individual animals and herds will support herd monitoring and control efforts. Currently, culturing results take 16 weeks. Kay Faaberg, a molecular biologist, leads a team working to develop a quicker test. The group has already developed and evaluated an experimental DNA-based polymerase chain reaction (PCR) test. With additional funding, an improved DNA-based PCR test will be developed using information from the Kapur sequencing project. When perfected, a very small amount of fecal material amplified in a PCR test will allow detection of Johne's within two days. A group led by veterinary geneticist Doug Weiss has identified different immune responses to M. paratuberculosis compared to that for other bacteria. Once those components are known, tools can be used to identify susceptible and resistant cattle. Cows that are uninfected will become sources of disease-resistant, healthy replacement animals for other herds. "Over the next few months, we expect to determine if disease susceptibility is linked to differential gene expression. If true, we could breed this disease out of Minnesota dairy herds," says Weiss. Scott Wells and Eran Raizman collect data for a risk assessment on a dairy farm. Calves are isolated from the mature herd to reduce spread of infection. Several projects have been initiated to develop effective control programs through herd management. Nine Minnesota dairy herds are currently participating in a demonstration herd control project. Records of milk production, cow reproduction, and herd culling will be collected. Reductions in disease and infection are being measured after changes in management practices on the farm based on a risk assessment approach. A study to evaluate the potential role of wildlife (deer and rabbits) and the environment in the transmission of Johne's involves 90 dairy farms. Two Minnesota dairy farms are being monitored to evaluate factors related to the onset of fecal shedding and clinical disease. The goals are to identify management practices that could slow the onset of clinical disease in infected herds and to estimate the cost of the disease. Recommendations "Even as we are monitoring dairy herds to determine how to best control the disease, motivated producers have to act as if every cow is infected," Wells said. "At this point our tests are not adequate, but we have identified ways to reduce the onset of Johne's disease in infected cows." The Minnesota Johne's Working Group makes the following recommendations: · Because there is a fecal-oral connection in the spread of the disease, University veterinarians recommend that calves be born in a clean, dry area and raised away from adult cows and their manure. · Colostrum--the first milk after calving that is essential to a calf's immune system--is commonly collected and fed to newborn calves. On some farms, that colostrum is pooled and fed to all newborns. If one of the mothers carried Johne's, all of those calves would become infected. A second recommendation is that each calf gets only its mother's colostrum. · A third recommendation is to feed milk replacer to calves instead of unpasteurized and often unsaleable milk produced when cows are treated with antibiotics. Sandra Godden, an epidemiologist, and Joellen Feirtag, a food scientist, are experimenting with pasteurization of waste milk to inactivate pathogens that could infect calves. Research veterinarians are now meeting across Minnesota with dairy producers and veterinarians to communicate this research and gather ideas to implement the results. --Arlene West Scott Wells and Sandra Godden are in the Department of Clinical and Population Sciences. Vivek Kapur and Doug Weiss are in the Department of Veterinary Pathobiology. Kay Faaberg is in the Minnesota Veterinary Diagnostic Laboratory. All are in the College of Veterinary Medicine. Joellen Feirtag is in the Department of Food Science and Nutrition, College of Agricultural, Food and Environmental Sciences./p> More information is available at http://www.cvm.umn.edu/dairycenter/johnes. back to contents