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Iowa State University

Plant Sciences

2007

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Continuing Education For Iowa Commercial Pesticide Applicators, Jean Mcguire Dec 2007

Continuing Education For Iowa Commercial Pesticide Applicators, Jean Mcguire

Integrated Crop Management News

Four continuing instructional courses (CIC) will be held in February and March to offer continuing education credit for Iowa commercial pesticide applicators. These programs will be held around the state at Iowa State University Extension county offices.


Evaluation Of Corn Rootworm Hybrids, Marlin E. Rice, James D. Oleson, Jon J. Tollefson Dec 2007

Evaluation Of Corn Rootworm Hybrids, Marlin E. Rice, James D. Oleson, Jon J. Tollefson

Integrated Crop Management News

This past summer, we evaluated corn rootworm technologies in side-by-side experiments at four locations in Iowa (Ames, Crawfordsville, Nashua, and Sutherland). The objective was to measure the degree of root protection and standability provided by the corn rootworm Cry proteins in each of three technologies, and then to compare them to a standard soil insecticide--Aztec® 2.1G. These field trials measured performance in protecting corn roots under a wide range of environmental conditions. Performance was measured as root injury, product consistency, and plant lodging. All tests were planted on continuous corn ground that was planted late the previous year to ...


Field Testing Of N-Hibit™ Seed Treatment In 2007 For Management Of Scn In Iowa, Gregory L. Tylka, Christopher C. Marett Dec 2007

Field Testing Of N-Hibit™ Seed Treatment In 2007 For Management Of Scn In Iowa, Gregory L. Tylka, Christopher C. Marett

Integrated Crop Management News

N-Hibit™ is a seed-treatment that contains harpin protein, a compound that can stimulate plant defense responses. N-Hibit™ is now being sold in the United States for management of the soybean cyst nematode (SCN). Iowa State University evaluated the effects of N-Hibit™ seed treatment on soybean yield and SCN population densities in experiments at nine locations throughout Iowa. Experiments were conducted in Albert City, Mason City, and Manchester in northern Iowa; Cambridge, Farnhamville, and Urbana in central Iowa; and Council Bluffs, Crawfordsville, and Melrose in southern Iowa. The work was supported by the soybean checkoff through funds from the Iowa Soybean ...


Rice Steps Down As Executive Editor, Marlin E. Rice Dec 2007

Rice Steps Down As Executive Editor, Marlin E. Rice

Integrated Crop Management News

During the past 19 years, I have served as the executive editor of this newsletter, and at the end of this year, I will step down from that responsibility. When I first assumed this role in 1988, the newsletter was known as Crops, Soils and Pests Newsletter, and it was printed on yellow paper with no photographs. During that year, there were 1,464 paid subscribers.


Fungicides For Soybean: Considerations For 2008, Daren S. Mueller Dec 2007

Fungicides For Soybean: Considerations For 2008, Daren S. Mueller

Integrated Crop Management News

Even though soybean rust was found in Iowa in 2007, the pathogen cannot survive in Iowa. The pathogen can only survive on living plant tissue of susceptible plants. Likely overwintering sites are in Florida and Texas on kudzu and in Central America on legumes, such as jicama and soybean. This means the risk of rust getting to Iowa in 2008 is the same as it was at the beginning of past years. For rust to get to Iowa, it will need to successfully overwinter somewhere in the South and retrace the path it traveled in 2007.


Yield Responsiveness Of Corn To Foliar Fungicide Application In Iowa, Alison E. Robertson, Lori Abendroth, Roger W. Elmore Dec 2007

Yield Responsiveness Of Corn To Foliar Fungicide Application In Iowa, Alison E. Robertson, Lori Abendroth, Roger W. Elmore

Integrated Crop Management News

An estimated three million acres of corn in Iowa were sprayed mid-season with fungicides (strobilurin or a strobilurin/triazole combination) in 2007. Reasons for spraying vary and include the high price of corn, potential to control diseases, and a possibility of improved yield from "plant health" benefits. Until this year, fungicide applications to production corn fields were rarely practiced in Iowa because they were not profitable. In addition, many of the hybrids grown today have good overall tolerance to foliar diseases.


New Distribution Format For Icm Newsletter, Wendy Wintersteen, Gerald A. Miller Dec 2007

New Distribution Format For Icm Newsletter, Wendy Wintersteen, Gerald A. Miller

Integrated Crop Management News

The print version of the Integrated Crop Management (ICM) Newsletter will be discontinued at the close of the 2007 calendar year. A new distribution format of the ICM Newsletter is planned for 2008. Discontinuation of the printed version was a difficult decision. However, in recent years, we have experienced a steady decrease in the number of subscribers for the print version and a steady increase in printing, design, handling and shipping costs. During the newsletter’s 19-year run, ISU was the first land-grant university to publish a full color crops newsletter and deliver it to subscribers that same week. This ...


Iowa Seed Directory Offers Quality Seed Options, Jessica L. Vogel Dec 2007

Iowa Seed Directory Offers Quality Seed Options, Jessica L. Vogel

Integrated Crop Management News

Farmers and gardeners looking for quality-assured seed to plant can order a free 2007 Iowa Seed Directory from the Iowa Crop Improvement Association (ICIA). Seed production information from more than 100 producers is included in this year's directory. Iowa Seed Directory listings include ICIA members who range from farmer-owned enterprises to multi-national seed companies. The directory lists fields that were inspected for genetic identity and purity during the 2007 season. The Iowa Seed Directory is published annually as a resource for quality soybean, oat, wheat, and native prairie species seeds.


Surveying Iowa For Scn, Gregory L. Tylka, Alison E. Robertson Dec 2007

Surveying Iowa For Scn, Gregory L. Tylka, Alison E. Robertson

Integrated Crop Management News

Most crop professionals in the Midwest recognize the soybean cyst nematode (SCN) as a widespread, yield-limiting factor. But until the mid-1990s, little was known about the actual distribution of SCN throughout the region. In 1995 and 1996, Iowa State University plant pathologists collaborated with the USDA National Agricultural Statistics Service (NASS) personnel to collect samples from hundreds of randomly selected fields in Minnesota, Iowa, Missouri, Illinois, Indiana, and Ohio. The work was supported by the soybean checkoff through funds from the North Central Soybean Research Program.


Soybean Rust: A Year In Review, Daren S. Mueller Dec 2007

Soybean Rust: A Year In Review, Daren S. Mueller

Integrated Crop Management News

During the 2005 and 2006 growing seasons, soybean rust was not a threat for Iowa soybean growers. This year was a different story, as soybean rust was established fairly early in the season in Texas and Louisiana creating the potential for soybean rust to get to Iowa during the growing season. Thankfully, soybean rust was not found while soybean plants were in a vulnerable stage; however, soybean rust was found in a field in Dallas County, Iowa, on Tuesday, September 25, 2007. Since the initial find, soybean rust was confirmed in 13 additional counties in Iowa (Figure 1).


A Possible Constraint On Regional Precipitation Intensity Changes Under Global Warming, W. J. Gutowski Jr., E. S. Takle, K. A. Kozak, J. C. Patton, R. W. Arritt, J. H. Christensen Dec 2007

A Possible Constraint On Regional Precipitation Intensity Changes Under Global Warming, W. J. Gutowski Jr., E. S. Takle, K. A. Kozak, J. C. Patton, R. W. Arritt, J. H. Christensen

Geological and Atmospheric Sciences Publications

Changes in daily precipitation versus intensity under a global warming scenario in two regional climate simulations of the United States show a well-recognized feature of more intense precipitation. More important, by resolving the precipitation intensity spectrum, the changes show a relatively simple pattern for nearly all regions and seasons examined whereby nearly all high-intensity daily precipitation contributes a larger fraction of the total precipitation, and nearly all low-intensity precipitation contributes a reduced fraction. The percentile separating relative decrease from relative increase occurs around the 70th percentile of cumulative precipitation, irrespective of the governing precipitation processes or which model produced the ...


Genetic Diversity In Hypericum And Aflp Markers For Species-Specific Identification Of H. Perforatum L., Ryan J. Percifield, Jennifer S. Hawkins, Joe-Ann Mccoy, Mark P. Widrlechner, Jonathan F. Wendel Dec 2007

Genetic Diversity In Hypericum And Aflp Markers For Species-Specific Identification Of H. Perforatum L., Ryan J. Percifield, Jennifer S. Hawkins, Joe-Ann Mccoy, Mark P. Widrlechner, Jonathan F. Wendel

NCRPIS Publications and Papers

One of the top-selling medicinal products worldwide is Hypericum perforatum (St. John's Wort). Despite its cosmopolitan distribution and utilization, little is known regarding the relationship of the bioactive compounds in H. perforatum to the plants from which they are purportedly derived. In this study, amplified fragment length polymorphism (AFLP) analysis of 56 Hypericum accessions, representing 11 species, was conducted to gain a better understanding of diversity within Hypericum species, especially within cultivated accessions of H. perforatum, and to establish a molecular methodology that will provide breeders and regulators with a simple, affordable, and accurate tool with which to identify ...


Dominant Species Constrain Effects Of Species Diversity On Temporal Variability In Biomass Production Of Tallgrass Prairie, H. Wayne Polley, Brian J. Wilsey, Justin D. Derner Dec 2007

Dominant Species Constrain Effects Of Species Diversity On Temporal Variability In Biomass Production Of Tallgrass Prairie, H. Wayne Polley, Brian J. Wilsey, Justin D. Derner

Ecology, Evolution and Organismal Biology Publications

Species diversity is thought to stabilize functioning of plant communities. An alternative view is that stability depends more on dynamics of dominant species than on diversity. We compared inter-annual variability (inverse of stability) of aboveground biomass in paired restored and remnant tallgrass prairies at two locations in central Texas, USA. Data from these two locations were used to test the hypothesis that greater richness and evenness in remnant than restored prairies would reduce variability in aboveground biomass in response to natural variation in rainfall. Restored prairies were chosen to be similar to paired remnant prairies in characteristics other than species ...


Toward Sequencing Cotton (Gossypium) Genomes, Z. Jeffrey Chen, Brian Eric Scheffler, Elizabeth Dennis, Barbara A. Triplett, Tianzhen Zhang, Wangzhen Guo, Xiaoya Chen, David M. Stelly, Pablo D. Rabinowicz, Christopher D. Town, Tony Arioli, Curt Brubaker, Roy G. Cantrell, Jean-Marc Lacape, Mauricio Ulloa, Peng Chee, Candace Haigler, Richard G. Percy, Alan R. Gingle, Sukumar Saha, Thea Wilkins, Robert J. Wright, Allen Van Deynze, Yuxian Zhu, Shuxun Yu, Ibrokhim Abdurakhmonov, P. Ananda Kumar, Mehboob-Ur- Rahman, Yusuf Zafar, John Z. Yu, Russell J. Ohel, Jonathan F. Wendel, Andrew H. Paterson Dec 2007

Toward Sequencing Cotton (Gossypium) Genomes, Z. Jeffrey Chen, Brian Eric Scheffler, Elizabeth Dennis, Barbara A. Triplett, Tianzhen Zhang, Wangzhen Guo, Xiaoya Chen, David M. Stelly, Pablo D. Rabinowicz, Christopher D. Town, Tony Arioli, Curt Brubaker, Roy G. Cantrell, Jean-Marc Lacape, Mauricio Ulloa, Peng Chee, Candace Haigler, Richard G. Percy, Alan R. Gingle, Sukumar Saha, Thea Wilkins, Robert J. Wright, Allen Van Deynze, Yuxian Zhu, Shuxun Yu, Ibrokhim Abdurakhmonov, P. Ananda Kumar, Mehboob-Ur- Rahman, Yusuf Zafar, John Z. Yu, Russell J. Ohel, Jonathan F. Wendel, Andrew H. Paterson

Ecology, Evolution and Organismal Biology Publications

Despite rapidly decreasing costs and innovative technologies, sequencing of angiosperm genomes is not yet undertaken lightly. Generating larger amounts of sequence data more quickly does not address the difficulties of sequencing and assembling complex genomes de novo. The cotton (Gossypium spp.) genomes represent a challenging case. To this end, a coalition of cotton genome scientists has developed a strategy for sequencing the cotton genomes, which will vastly expand opportunities for cotton research and improvement worldwide.


Cellulose To Ethanol: An Update On The Poet Bio-Refinery In Emmetsburg, Paul Kassel, Jill Euken Nov 2007

Cellulose To Ethanol: An Update On The Poet Bio-Refinery In Emmetsburg, Paul Kassel, Jill Euken

Proceedings of the Integrated Crop Management Conference

Grain-based ethanol production has greatly expanded in Iowa in the past 5 years. Future growth of ethanol production will depend on cellulosic feed stocks. Some of these feed stocks may include grass/forage, municipal wastes and crop residues. Much of the technology to convert cellulosic feed stocks to ethanol is still being developed.


Soybean Rust Makes It To Iowa, Daren Mueller, Xun Li, X. B. Yang Nov 2007

Soybean Rust Makes It To Iowa, Daren Mueller, Xun Li, X. B. Yang

Proceedings of the Integrated Crop Management Conference

Soybean rust, Phakopsora pachyrhizi, was first reported in the United States in November 2004 and survived winters on kudzu in the south. Soybean rust can reduce soybean yields and/or significantly increase the cost of soybean production when the disease occurs during the growing season with high incidence and severity. During the 2005 and 2006 growing seasons, soybean rust was not a threat for Iowa soybean growers. This year was a different story, as soybean rust was established fairly early in the season in Texas and Louisiana creating the potential for soybean rust to get to Iowa during the growing ...


Coupling Manure Injection With Cover Crops To Enhance Nutrient Cycling, Jeremy W. Singer, Cynthia A. Cambardella, Thomas B. Moorman Nov 2007

Coupling Manure Injection With Cover Crops To Enhance Nutrient Cycling, Jeremy W. Singer, Cynthia A. Cambardella, Thomas B. Moorman

Proceedings of the Integrated Crop Management Conference

Large-scale hog (Sus scroja) production is a major agricultural enterprise in the Midwest. Large numbers of confined hogs produce about 50 million tons per year of swine manure in Iowa alone. Rapid expansion of concentrated animal feeding operations (CAFOs) has resulted in increased concentrations of manure nutrients in surface waters which contribute about 15% of the total nitrate load in the Mississippi River Basin. Producers are being encouraged to develop manure management practices that fulfill crop production requirements, while minimizing the potential for environmental pollution. The most commonly used manure management practice in the Midwest involves fall application to land ...


Soybean Plant Population For Maximum Economic Return, Palle Pedersen Nov 2007

Soybean Plant Population For Maximum Economic Return, Palle Pedersen

Proceedings of the Integrated Crop Management Conference

Conversations about soybean seeding rates have stimulated a great deal of interest among producers in recent years. The major reason for this interest, soybean seed costs have increased rapidly as new varieties with improved traits, better disease resistance, and higher seed yields have come to the market. In addition, a few seed companies have started to sell soybean seed by the seed count rather than the traditional "unit" with no price differentiation based on seed size. For this reason many growers have started to reduce their seeding rate. Attempting to reduce production costs through reduced seeding rates is desirable, however ...


What Are The Lasting Impacts Of Early-Season Problems In Corn?, Roger W. Elmore, Lori Abendroth Nov 2007

What Are The Lasting Impacts Of Early-Season Problems In Corn?, Roger W. Elmore, Lori Abendroth

Proceedings of the Integrated Crop Management Conference

Do early season problems 'disappear' in corn7 Plant-to-plant and in-field variability was a concern across numerous corn fields in 2007. In addition, fields had uneven seeding depths, shallow nodal root systems, sidewall compaction, and other problems were common. We will discuss the importance of uniformity in fields relative to yield partitioning and yield determination in corn. First we present a primer of early season root systems and then we present a list of 9 early-season management/environmental factors that affect plant-to-plant and in-field variability and reduce yield potential. Anything that disrupts early-season growth can have a negative impact on yield ...


How Plants Survive The 'Herbicide Of The Century', Bob Hartzler Nov 2007

How Plants Survive The 'Herbicide Of The Century', Bob Hartzler

Proceedings of the Integrated Crop Management Conference

Glyphosate is the most widely used herbicide in the world for several reasons, including: 1) high level of effectiveness, 2) flexibility in application, 3) large margin of crop safety in glyphosate resistant crops, and 4) safety to applicators and the environment. Glyphosate was used for more than 20 years before weeds developed resistance to the chemical. This relative low risk of glyphosate resistance compared to other herbicide classes resulted in considerable debate on how best to use the technology to minimize selection of resistant biotypes. This paper will briefly review the factors that make glyphosate such an effective herbicide, and ...


Boosting Pasture Production, Stephen K. Barnhart Nov 2007

Boosting Pasture Production, Stephen K. Barnhart

Proceedings of the Integrated Crop Management Conference

The majority of the 'pasture questions' that I receive as Extension Forage Specialist deal with the various aspects of pasture improvement, renovation, and establishing new pasture areas. A few of these kinds of questions are now coming from otherwise good pasture managers as well, who are planting more corn and soybeans and are looking for ways to maintain or increase the productivity of the remaining pasture acres. Some of the most practical ways to boost pasture production are fertilization, overseeding, and improved grazing management.


Managing Diseases And Pests With Seed Treatments, Gary P. Munkvold Nov 2007

Managing Diseases And Pests With Seed Treatments, Gary P. Munkvold

Proceedings of the Integrated Crop Management Conference

The use of seed treatments for corn and soybeans is a constantly evolving situation in terms of available products and targeted pests. Currently there are registered corn seed treatments that target at least five genera of fungi, eight different insect pests, and several types of nematodes. Targets for seed treatment include diseases caused by seedborne and soilborne fungi, seedborne bacteria, nematodes, and a variety of insects that feed on above-ground or below-ground plant parts. Active ingredients include contact and systemic fungicides, antimicrobial agents, systemic insecticides, and biological control agents. Seed treatment benefits are dependent on pest & disease pressure, environmental conditions ...


Soybean White Mold: What Have We Learned Since 1992?, Craig Grau Nov 2007

Soybean White Mold: What Have We Learned Since 1992?, Craig Grau

Proceedings of the Integrated Crop Management Conference

White mold, sometimes called Sclerotinia stem rot, remains an important disease of soybean in the midwest. Although other pathogens and pests are more consistent problems, management of white mold usually entails an integrated and often complicated integration of management practices. A white mold management system may fail if one weak link in chain exists. White mold causes direct yield loss, but yield potential may be lost in the absence of the disease if growers have made management adjustments that result in lower yield potential. White mold is best managed by an integrated approach of selecting soybean varieties with the highest ...


Weed Management In 2008 - New Opportunities, Existing Issues And Anticipated Problems, Michael D.K. Owen Nov 2007

Weed Management In 2008 - New Opportunities, Existing Issues And Anticipated Problems, Michael D.K. Owen

Proceedings of the Integrated Crop Management Conference

There are a number of new opportunities in weed management for 2008. However, issues continue to surface and problems are likely to escalate in the future. Specifically, there are new herbicide resistant crop options that will be available in the near future, new herbicides and changes in existing proprietary herbicides. Glyphosate continues to dominate as the weed control tactic of choice, and given the importance of bio-renewable fuels in the future, more herbicide resistant corn will be planted. The selection pressure that will be imposed on the weed communities as a result of grower adoption glyphosate resistant corn, as well ...


Optimizing Soybean Yield By Better Management Of Radiation And Water Use!, James E. Specht Nov 2007

Optimizing Soybean Yield By Better Management Of Radiation And Water Use!, James E. Specht

Proceedings of the Integrated Crop Management Conference

Humans grow crops to harvest the sun. This might seem like a simplistic statement, but plants are the only living species on this planet that can directly convert solar energy into chemical energy in the form of food, fiber, or fuel. The photosynthetic production of vegetative and seed biomass can be described with this simplified reaction:


Plant-Parasitic Nematodes On Corn: Old Foes And A Possible New Nemesis, Gregory L. Tylka Nov 2007

Plant-Parasitic Nematodes On Corn: Old Foes And A Possible New Nemesis, Gregory L. Tylka

Proceedings of the Integrated Crop Management Conference

Plant-parasitic nematodes are microscopic worms, usually soil borne, that feed on plants. Nematodes that feed on and damage corn have been known to occur in Iowa and other parts of the Midwest since the 1950s. But recent and upcoming changes in Iowa's cropping practices have some anticipating an increase in damage and yield loss to corn from nematodes. Most corn nematode species maintain their populations when soybeans or alfalfa are grown, but repeated cropping of corn may cause nematode populations to flare up. Also, use of transgenic, insect-resistant corn hybrids for corn rootworm control may reduce the amount of ...


Corn Diseases: Reviewing The 2007 Growing Season, Alison Robertson Nov 2007

Corn Diseases: Reviewing The 2007 Growing Season, Alison Robertson

Proceedings of the Integrated Crop Management Conference

Several diseases were prevalent in corn during the 2007 growing season. Weather conditions varied greatly across the state and as a result disease problems did too. An increase corn following corn acres (10.3%) impacted the incidence of several diseases.


Impact Of Bioenergy Industry On Soil And Water Resources, Richard M. Cruse, Carl Herndl, Elena Polush Nov 2007

Impact Of Bioenergy Industry On Soil And Water Resources, Richard M. Cruse, Carl Herndl, Elena Polush

Proceedings of the Integrated Crop Management Conference

Recent reports and publications such as that of Perlack et al, 2005 and Burton et al, 2006 indicating a high capacity of this nation's lands to produce feedstocks for renewable fuels have created large expectations in rural America, in Congress, and on Wall Street. Meeting these expectations while preserving our soil and water resources may be a challenge or an opportunity, depending upon how the bioenergy industry develops. It presents a challenge because the plant residues serving as our most important soil and water conservation tool are also required for fuel production in the cellulosic liquid fuel industry. It ...


Stop Sds: Prioritizing Management Approaches That Best Fit Your Fields, X. B. Yang, S. S. Navi Nov 2007

Stop Sds: Prioritizing Management Approaches That Best Fit Your Fields, X. B. Yang, S. S. Navi

Proceedings of the Integrated Crop Management Conference

Sudden death syndrome (SDS) is a mid- to late-season, soil borne disease that occurs primarily in soybean fields with high yield potential. First observed in Arkansas in 1971, SDS now causes significant losses in Midwestern states such as Illinois and Indiana and is considered the most important fungal disease in causing yield loss in the North Central Region. The disease was first noticed in Iowa in 1993. Now the disease has been found from border to border in Iowa. It occurs annually in eastern Iowa and epidemics occur frequently in recent years. Yield losses due to SDS vary widely. SDS ...


Current Status Of The Soybean Cyst Nematode As A Threat To Soybean Production In The Midwest, Greg Tylka Nov 2007

Current Status Of The Soybean Cyst Nematode As A Threat To Soybean Production In The Midwest, Greg Tylka

Proceedings of the Integrated Crop Management Conference

The soybean cyst nematode (SCN) has plagued Iowa soybean production since the 1980s. It continues to be a serious yield-limiting pest of soybeans throughout the state, causing yield losses directly as well as indirectly by intensifying other serious soybean diseases. SCN is widely distributed throughout the state. The nematode has excellent long-term survival and its population densities build up each year that susceptible soybeans are grown, regardless of the rainfall and temperature that occur during the growing season. Up to 40% yield loss can occur without the appearance of any aboveground symptoms (Wang et al., 2003).