Research on Insect Flight Could Improve Pest Management
Researchers Tap Genetic Biodiversity For Benefit of Soybean Producers
Center for Soybean Improvement Takes Innovative Research Approach
Soybean Rust Workshop Aims To Protect U.S. Crop
The NSRL Bulletin is published three times a year by the National Soybean Research Laboratory at the University of Illinois, 170 National Soybean Research Center, 1101 W. Peabody Drive, Urbana, IL 61801; telephone (217)244-1706; e-mail nsrl@uiuc.edu; FAX (217)244-1707. James Sinclair, director; Robert J. Wynstra, editor; David Riecks, photographer; Lynn Hawkinson Smith, graphic designer.
Unless otherwise stated, articles may be reproduced or quoted if credit is given to the NSRL Bulletin. The National Soybean Research Laboratory at the University of Illinois is an affirmative action and equal opportunity institution.
Presented by
College of Agriculture University of Illinois at Urbana-Champaign National Soybean Research Laboratory 170 National Soybean Research Center 1101 West Peabody Drive Urbana, IL 61801-4723
Research on Insect Flight Could Improve Pest
Management
One key piece of information for managing aphids and other migratory insects is knowing when they are likely to appear. With this in mind, National Soybean Research Laboratory entomologist Michael E. Irwin is taking a major step toward developing an early forecast system by studying aerobiology or insect flight.
"This approach is practical," says Irwin, who serves as professor in the Department of Natural Resources and Environmental Sciences at the University of Illinois. "The lack of research on how insects move is a major bottleneck, but researchers are finding ways to share technology and information across projects. Eventually we will characterize the movement of flying insects, such as aphids."
Irwin and his colleagues at the University of Illinois, Scott Isard and Gail Kampmeier, are part of the Alliance for Aerobiology Research. This national group of scientists fosters an integrated, multidisciplinary approach to research on how insects migrate and disperse.
Irwin's pioneering research on the mechanics of aphid flight began more than a decade ago. Among the aphids he is closely studying are those species that transmit soybean mosaic virus.
"Soybean mosaic virus epidemics occur when the aphids arrive at just the right time," he says. "If we import seeds that carry inoculum or if aphids native to China get in, we could see a lot more of it. It behooves us to be prepared. If we don't know the mechanics of the causes, it will be hard to know how or when to intercede."
In many of the major soybean growing areas, the species of aphids that produce the most economic damage die out each winter. Yet they are back each growing season, arriving on wind currents along with black cutworm, potato leafhopper, and other insect pests.
To track aphids, Irwin has collaborated with scientists who have expertise in plant diseases, engineering, crop development, and weather. As part of a 1984 project, the scientists collected corn leaf aphids in pods attached to helicopters.
Since then, they have used radar to detect aphids in air currents that move them north from the Gulf of Mexico. Researchers even have tethered the tiny aphids and put them in a wind tunnel to measure the use of energy in flight. Computer modeling has proven an important tool for studying population dynamics.
As a result of this broad collaboration, scientists today can catch an aphid high in the air and determine how long it has been flying and where it came from. They know that aphids land only if they see the ground. Therefore, if aphids get caught in a wind current at night, they are likely to continue flying until daylight.
Aphids are not randomly distributed through the air. Instead, they form layers in the air currents. Some are predisposed to flapping their wings and moving up to higher air currents, while some are not.
Aphids of different genetic background may travel together. In different years, aphids may invade from different places. Irwin also notes that international boundaries are not barriers for aphids. Studies show the genetics of aphids are not always consistent, which suggests there is no permanent source of aphids within the United States.
Studies using helicopters to sample aphids in different atmospheric conditions indicate that temperature is a factor governing their distribution in the air. Strong night currents will move aphids north from the Gulf of Mexico to different regions, depending on where they are in the atmospheric layers. They land in waves throughout the season. Once a wave arrives, the aphids will move in a field but will not catch another air current.
"Now we can predict how far aphids go in the night and what level they will be at," Irwin says. "Understanding the whole system makes it feasible to develop an area-wide integrated pest management approach for controlling aphids."
The next step is to find out more about aphid behavior. Also, certain studies must be moved from the laboratory to the field where multiple factors influence aphid populations and behavior.
In the future, it might be possible to manage migratory pests of the soybean at the point of origin rather than at the destination, Irwin suggests.
"At the very least, it might be possible to predict where
migratory pests will end up and alert farmers," he says.
"It might even be possible to trick aphids into landing in
the wrong areas or at the wrong times. There are many
possibilities for improved pest management once the whole system
is understood."
Researchers Tap Genetic Biodiversity For Benefit
of Soybean Producers
Millions of years after their ancestors parted company on the northern shores of Australia, the world-roaming soybean plant, Glycine max, and its wild perennial relative, Glycine tomentella, have been reunited by researchers from Australia and the United States.
"It's a bit like a botanical version of Wuthering Heights," says Tony Brown, researcher with the Australian Commonwealth Scientific and Industrial Research Organization (CSIRO) in Canberra. "Millions of years ago the ancestors of these two species were wrenched apart. Now science has brought them together."
The breakthrough came after nearly 15 years of painstaking laboratory work by Theodore Hymowitz, professor of plant genetics, and his co-workers in the Department of Crop Sciences at the University of Illinois. The goal was to produce a viable descendant through cross breeding of the common soybean with Glycine tomentella, which was found by CSIRO scientists off the coast of Queensland on Brampton, a Great Barrier Reef island. In 1993, he succeeded for the first time in producing fertile soybeans containing genes from the Australian relative.
Glycine tomentella, which is commonly known as woolly Glycine, is a short, twiny perennial with purple to reddish pea-like flowers. It lives in open eucalyptus woodlands in northeastern and western Australia. Researchers hope that the cross between the soybean and this wild relative will produce new types of soybeans that can thrive in dry conditions and are resistant to major diseases, such as rust.
"I don't think most people realize that the native plants of Australia include many relatives of important world crops," Brown says. "Such wild biodiversity is an important source of new genetic material for world agriculture."
The ancestor of the soybean and its Australian cousins probably evolved in Southeast Asia tens of millions of years ago. Australia at the time was much further south than it is today. After slowly drifting north, the Australian continent finally collided with Southeast Asia about 15 million years ago.
The soybean ancestor was one of many Asian plants that used this opportunity to move into Australia. The plants that stayed in Asia evolved into a wild annual type of soybean that was domesticated in China about 1100 B.C. In Australia, the soybean ancestor evolved into at least 16 different perennial species that today grow wild across much of the continent and on many south Pacific islands.
As it evolved to suit Australian conditions, woolly Glycine developed traits that allow it to survive droughts and live in salty soil near the seashore. Most importantly for modern soybean farmers, it also developed resistance to the damaging disease known as soybean rust.
"The Australian Glycine species represent a precious genetic resource for one the world's most important crops," Brown says. "They show just how valuable Australia's native biodiversity is to the world."
At the University of Illinois, Hymowitz began his research program in 1976 with the idea of tapping this source of genetic biodiversity for the benefit of soybean producers. Taking advantage of such biodiversity is especially important as selection has narrowed the germ plasm base to fewer varieties grown over larger and larger areas.
"Unfortunately, pathogens and pests relentlessly attack the soybean," Hymowitz says. "Breeders can only develop varieties to resist these pests and pathogens if they have material that has sources of resistance."
Key sources of this resistance are the wild relatives of the soybean found in Australia and the south Pacific islands. At the time Hymowitz began his research only six wild perennial species were known. Today the number stands at 16.
"You expect the wild material grown under different environmental conditions to have greater variation," he says. "As sources of genetic material, the wild soybean relatives are superb."
The soybean, like corn, is really a domesticated plant that could not survive without human intervention. An important obstacle to successfully crossing the wild and domestic varieties, however, was the lack of fertility in the succeeding generation.
"We had bottleneck after bottleneck," Hymowitz says. "You cross them and you get a sterile plant. So we had to overcome that sterility barrier and that took a long, long time."
Finally in 1993, Hymowitz, along with his colleague Ram Singh, created a series of fertile plants containing all 40 soybean chromosomes plus one from woolly Glycine. One of the extra chromosomes carries the trait of resistance to soybean rust, which is a major limiting factor to soybean production in much of southeastern Asia.
"Now rust has been found in soybean fields in Hawaii," he says. "If it comes to the mainland of the United States, the impact would be enormous. Much of the production in the southern states would be threatened"
To meet this threat, Hymowitz is working with Tony Brown and other scientists from CSIRO to screen lines that carry resistance to the Asian rust.
"There is no other known source of field resistance to
rust," Hymowitz says. "With patience and time, the
whole soybean industry and the public ultimately should benefit
from this work with the genetic material from the wild soybean
relative."
Center for Soybean Improvement Takes Innovative
Research Approach
In 1992, the University of Georgia united a diverse group of scientists into a problem-solving unit known as the Center for Soybean Improvement. The aim was to bring researchers and educators from several different disciplines together to better deal with many of the disease, insect, and management problems that have affected soybean production in the Southeast.
"The Center for Soybean Improvement isn't a place," says Roger Boerma, a soybean breeder and geneticist, who serves as coordinator of the Center. "It's a group of people, including researchers, growers, processors, and educators, dedicated to promoting cooperation and innovation among soybean scientists."
Under this concept, scientists from agronomy, plant pathology, applied economics, food science and technology, agricultural engineering, and entomology at Georgia Agricultural Experiment Stations located in Athens, Griffin, and Tifton have worked together to speed the development of soybeans with superior yields, increased drought resistance, and multiple pest resistance. They also have moved ahead on improved management systems to control weeds, diseases, and insect pests.
"These efforts are designed to enhance Georgia and Southeastern agriculture by providing the maximum profit from soybean production while reducing the risk of environmental damage and improving the safety of soybean feed and food products," Boerma says.
Today the Center for Soybean Improvement at the University of Georgia is expanding this mission to include scientists from across the Southeast. The idea is to blend the expertise in soybean research and education at the University of Georgia with the soybean knowledge available at universities in the neighboring states of Alabama, Florida, North Carolina, and South Carolina.
"In Georgia, we have a large number of scientists with time devoted to soybeans," Boerma says. "We want to provide our expertise to other states. And we want to benefit from their expertise as well."
One area of special interest for the Center is development of improved varieties that can dramatically increase yields and pest resistance. Varieties released through this effort already are producing 15 to 20 percent yield increases per acre that lessen the need for pesticides.
"As tools become more sophisticated, it is no longer possible for one person to possess all the skills necessary in genetic improvement programs," Boerma says. "The Center is one way we can bring together the people who have those skills."
Multiple pest-resistant varieties and new management systems are becoming increasingly important for soybeans because of environmental and health concerns and because many chemicals are losing federal approval. For example, most fumigant nematicides, once used to kill nematodes, are no longer available.
"The environment and what we do are interrelated," Boerma says. "It is clear that varieties with multiple pest resistance will need less chemical controls, resulting in less risk to the environment and reduced cost of production for soybean farmers."
The Center programs are supported in large part by soybean farmers through the Georgia Soybean Association and the Georgia Agricultural Commodity Commission for Soybeans. And, according to Boerma, it is farmers across the Southeast who stand to benefit most from this new approach to soybean improvement.
"To be competitive, we have to use the best technology available," he says. "With the large variety of crops grown in the Southeast, every state can't afford expertise in every crop. But, as a group of states, we collectively have the scientific resources needed to make the next major advancements in soybean production in our region."
Soybean Rust Workshop Aims To Protect U.S. Crop
Since the discovery of the disease known as soybean rust on three islands in Hawaii more than a year ago, a number of scientists have raised concerns that the soybean industry must be prepared to meet the threat should this devastating disease somehow be introduced into the continental United States. The concern was especially strong because the type of rust found in Hawaii appears closely related to the Asian isolates which have severely limited soybean production in much of southeast Asia.
"My attitude is that we cannot be complacent because the disease appears to be isolated to Hawaii," says James B. Sinclair, interim director of the National Soybean Research Laboratory. "There is one example after another where the unanticipated introduction of a disease-causing organism in the U.S. has proven devastating."
Soybean rust is caused by two types of fungi, Phakopsora pachyrhizi, which is found in Asia, and Phakopsora meibomiae, which is found in Latin America. Of these, the Asian variety is much more damaging to soybeans. A 1991 study found that introduction of the disease into the continental United States had the potential to reduce yields by 10 percent in nearly all soybean growing areas, with losses up to 50 percent in the Mississippi delta and southeastern costal areas.
Although soybean rust is not transmitted on seeds, it could be carried to the U.S. on crop debris or inadvertently by a returning tourist after visiting a soybean field in Hawaii. Most important, there is no resistance bred into existing U.S. commercial cultivars, and fungicide treatments would add substantially to the cost of production.
Recently nine scientific experts from across the United States gathered at the National Soybean Research Laboratory to discuss the state of knowledge about soybean rust. They also examined possible methods to control the spread of the disease and measures to protect the U.S. soybean crop should it be introduced in the future.
Major funding for this national workshop was provided by the United Soybean Board. Additional support came from the Office of Research in the College of Agricultural, Consumer and Environmental Sciences at the University of Illinois.
James B. Sinclair, interim director of the NSRL, and Glen L. Hartman, USDA plant pathologist at the NSRL, co-chaired the meeting. Other participants included: Morris R. Bonde, USDA; Joseph F. Hennen, Botanical Research Institute of Texas; Theodore Hymowitz, University of Illinois; Eloise M. Killgore, Hawaii Department of Agriculture; R.J. Singh, University of Illinois; Arnold T. Tschanz, USDA; and X.B. Yang, Iowa State University.
In a summary of the proceedings, the group reported that soybean rust is a potential threat to the soybean production industry in the continental United States, especially because the appearance of the disease in Hawaii suggests that long-distance dissemination is possible. Eradication of the fungal pathogen and the disease is not practical in Hawaii because of the huge host range of the fungi.
The group pointed out that early recognition is crucial for eradication from an area should the disease be introduced into the continental United States. The members urged the USDA Animal and Plant Health Inspection Service to prepare a detailed action and eradication plan for the disease prior to its introduction. They also emphasized the importance of increased international collaboration in studying this disease.
In support of these general conclusions, the workshop participants made a number of specific recommendations for short- and long-term research needs. High priority was given to development of rapid identification techniques and testing of available tolerant soybean lines for adaptability in the U.S. They further recommended increased collaboration with international scientists to speed development and testing of resistant lines derived from crosses between soybeans and wild relatives of the soybean.
A brief "white-paper" summary of the workshop recommendations is available from the NSRL. This summary will be followed later in the year by publication of detailed proceedings from the workshop, including major invited papers and full research recommendations.
Effective on August 21, the College of Agriculture at the University of Illinois officially was renamed the College of Agricultural, Consumer and Environmental Sciences. This change culminated more than two years of efforts to reshape the College of Agriculture to better meet the changing research, teaching, and outreach needs of the future.
In addition to the name change, the existing units in the College were reorganized into the following departments: Agricultural Engineering, Animal Sciences, Agricultural and Consumer Economics, Crop Sciences, Food Science and Human Nutrition, Human and Community Development, and Natural Resources and Environmental Sciences. Professor David Chicoine, former head of the Department of Agricultural Economics, was named interim dean replacing W.R. "Reg" Gomes, who left on September 1 to assume the position of vice-president in the California state university system.
The NSRL office will continue to report to Associate Dean Don Holt, who serves as director of the new Office of Research. The Office of Research will carry out most of the same functions as the former Agricultural Experiment Station. In my role as a professor of plant pathology, I will be serving in the newly created Department of Crop Sciences.
None of these structural changes in any way affect the basic goals and objectives of the NSRL. From the beginning, one of our primary objectives was to plan and conduct workshops on problem areas of interest to the entire U.S. soybean industry.
The first of these workshops was held at the NSRL from August 9 to 11. With support from the United Soybean Board and the Office of Research in the College of Agricultural, Consumer and Environmental Sciences, nine scientists from across the United States gathered to discuss the threat from soybean rust and to make recommendations for ways to protect the U.S. soybean crop. A "white-paper" summary of these proceedings is available from the NSRL office.
Once again the NSRL has launched its fall seminar series with the presentation of the third annual George A. Fluegel Memorial Lecture. The lecture was held in conjunction with the semi-annual meeting of the NSRL Advisory Committee.
This year's lecturer was S. Thad Jones, chief administrative
officer of Central Soya Company, Inc. His presentation provided
an important overview of value-added soybean technologies. At
least five additional NSRL seminars will be held during the
1995-1996 academic year as a further fulfillment of our mission
to provide a forum for presenting issues of importance to the
U.S. industry.
James B. Sinclair
Interim Director
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