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Iowa State University

Plant Sciences

2005

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Soybean Rust: Are We Out Of The Woods?, X. B. Yang Dec 2005

Soybean Rust: Are We Out Of The Woods?, X. B. Yang

Integrated Crop Management News

In the discussion board portion of a website, I recently read a message with a similar subject title by a producer. This question is also one producers in the North Central Region are asking because of the light occurrence of soybean rust this past season. Development of the disease was surprisingly slower than most of us had anticipated. In this article, I will address the questions raised by producers by reviewing what we learned this past growing season, which was summarized during the National Soybean Rust Symposium held last month.


Three-Year Summary Of Corn Rootworm Control Products, Marlin E. Rice, James Oleson Dec 2005

Three-Year Summary Of Corn Rootworm Control Products, Marlin E. Rice, James Oleson

Integrated Crop Management News

During the past three summers, corn rootworm insecticides and YieldGard Rootworm® corn were evaluated in side-by-side trials at several locations across the state. These field trials measured performance in protecting corn roots under a wide range of environmental conditions. Performance was then measured as root injury, product consistency, plant lodging, and grain yield. The same corn hybrid (non-rootworm) was planted for all of the insecticide treatments at each location and year, plus a YieldGard RW® hybrid that contained the cry protein for corn rootworm control.


Continuing Instructional Courses For Spring 2006, Keven Arrowsmith Dec 2005

Continuing Instructional Courses For Spring 2006, Keven Arrowsmith

Integrated Crop Management News

All certified applicators receive a small postcard in the spring and in the fall listing commercial applicator programs and dates. Applicators also receive a large postcard for the categories they are certified in. The large postcard gives the date, time, and list of counties offering the program.


Dead, Duplicate Or Discarded: Npgs Inactivation Guidelines, Mark P. Widrlechner Dec 2005

Dead, Duplicate Or Discarded: Npgs Inactivation Guidelines, Mark P. Widrlechner

NCRPIS Conference Papers, Posters and Presentations

No abstract provided.


Assessing Consumers' Valuation Of Cosmetically Damaged Apples Using A Mixed Probit Model, Chengyan Yue, Helen H. Jensen, Daren S. Mueller, Gail R. Nonnecke, Mark L. Gleason Dec 2005

Assessing Consumers' Valuation Of Cosmetically Damaged Apples Using A Mixed Probit Model, Chengyan Yue, Helen H. Jensen, Daren S. Mueller, Gail R. Nonnecke, Mark L. Gleason

CARD Working Papers

A mixed probit model was applied to survey data to analyzeconsumers’willingnessto buy apples with cosmetic damage caused by the sooty blotch and flyspeck (SBFS) disease complex. The analysis finds consumers will pay a premium for organic production methods and for apples with low amounts of SBFS damage. Behavioral variables such as experience in growing fruit significantly affect the willingness to buy applesofdifferentdamagelevels.Consumers’toleranceofveryblemishedapplesis limited and they trade off production technology attributes for cosmetic appearance. Better understanding of this trade-offisimportanttoorganicproducers’decisionsabout disease control.


Asian Soybean Rust In The U.S.: One Year And Counting, Greg Tylka, Alison Robertson, X. B. Yang Dec 2005

Asian Soybean Rust In The U.S.: One Year And Counting, Greg Tylka, Alison Robertson, X. B. Yang

Proceedings of the Integrated Crop Management Conference

Asian soybean rust is caused by the fungus Phakopsora pachyrhizi. This disease can seriously reduce soybean yields and/or significantly increase the cost of soybean production when the disease occurs with high incidence and severity Asian soybean rust was first identified in japan in 1902. The pathogen moved throughout Asia, Australia, and Africa throughout the 1900s before it was discovered in South America in 2000.In November 2004, Asian soybean rust was first discovered in the U.S. in Louisiana. At the time of the initial discovery of this disease in the U.S., most of the commercial soybean fields ...


Results Of On-Farm Studies On Deep Tillage, Paul Kassel Dec 2005

Results Of On-Farm Studies On Deep Tillage, Paul Kassel

Proceedings of the Integrated Crop Management Conference

The in-line ripper was promoted as a new tillage tool for area farmers in the fall of 2002 and 2003. The in-line ripper is described as a tillage implement that operates 16 to 20 inches deep, shatters the soil in a vertical pattern and does not disturb the surface crop residue. Yield claims were made showing a benefit of deep tillage (16 to 20 inches) with an in-line ripper. Some farmers used the in-line ripper on a large number of acres to reduce compaction problems and/or increase rooting depth of corn and soybean crops. However, other farmers raised the ...


Where Will Our Next Major Weed Problems Come From?, Bob Hartzler Dec 2005

Where Will Our Next Major Weed Problems Come From?, Bob Hartzler

Proceedings of the Integrated Crop Management Conference

Weed communities within agronomic fields are defined by the number of different species present and the relative abundance of the individual species. At any given time, three or four species within a field typically dominate the weed community, with the remaining species present at relatively low densities. A weed shift represents a change in the weed community within a field. The majority of shifts are caused by differential selection pressure placed on the weeds present in a field. Species or biotypes adapted to current weed management tactics increase, whereas weeds susceptible to those tactics decrease. The rate of change varies ...


Survey Of Soybean Diseases In Iowa, Alison Robertson, Forrest Nutter Jr. Dec 2005

Survey Of Soybean Diseases In Iowa, Alison Robertson, Forrest Nutter Jr.

Proceedings of the Integrated Crop Management Conference

Soybean producers and breeders are constantly striving to increase yields. Over the past decade, soybean diseases have been the primary factors that have most limited soybean yields. For example, estimated yield losses due to Phytophthora stem rot, and pod and stem blight in Iowa in 200 l were 1.8 million pounds each (Wrather et al, 2002). In 2002 in Iowa, 31.5 million pounds of soybeans were lost to foliar disease, and 2.5 million pounds to the stem disease sudden death syndrome (Wrather et al, 2002). Since plant pathogens substantially decrease the yield of crop plants, information on ...


The Iowa Corn And Soybean Variety Test: New And Improved!, Jim Rouse Dec 2005

The Iowa Corn And Soybean Variety Test: New And Improved!, Jim Rouse

Proceedings of the Integrated Crop Management Conference

The corn and soybean variety testing programs administered by Iowa State University and the Iowa Crop Improvement Association have now been merged into a single program. This presents a unique opportunity to make some procedural changes that will economize our testing efforts. At the same time, we are making modifications to the configuration of the testing program to increase awareness of and participation in the tests. Current and upcoming changes will be described, beginning with a description of our basic operation. Seed companies from Iowa and surrounding states, who market seed in Iowa, are eligible to submit corn and soybean ...


The Current State Of Herbicidal Weed Control, Micheal D. K. Owen Dec 2005

The Current State Of Herbicidal Weed Control, Micheal D. K. Owen

Proceedings of the Integrated Crop Management Conference

The recent adoption of GM crops resulted in a dramatic impact on the use of herbicides for weed control in Iowa. Particularly, glyphosate-resistant soybeans dominate the varieties that are planted and anticipated increases in grower adoption of glyphosate-resistant corn have resulted in the unprecedented use of one herbicide being applied to most of the row crop acres in Iowa. There are a number of important benefits for the use of glyphosate-resistant crops and the concomitant applications of glyphosate. The benefits that can be objectively established include broad-spectrum weed control, the consistency of weed control, minimal concerns for crop injury, and ...


Long-Term Weed Management Using Diverse Crop Rotation Systems, Paula Westerman, Matt Liebman Dec 2005

Long-Term Weed Management Using Diverse Crop Rotation Systems, Paula Westerman, Matt Liebman

Proceedings of the Integrated Crop Management Conference

Now that the elevators are filled with grain, farm life is slowing down, and farmers in Iowa can look back at a year with generally good yields, it is important to recognize that our wealth and prosperity are not without a cost. Nationwide, herbicide use has not diminished, despite the use of glyphosate resistant genetically engineered crops (http://www.epa.gov/oppbead1/pestsales/), and intensive row-cropping in combination with the use of high rates of synthetic fertilizer and drainage tiles contributes to high concentrations of nitrate in surface waters (Randall et al., 1997; Schilling and Libra, 2000) and hypoxia in ...


Regional Approach To Making Nitrogen Fertilizer Rate Decisions For Corn, John E. Sawyer, Emerson D. Nafziger Dec 2005

Regional Approach To Making Nitrogen Fertilizer Rate Decisions For Corn, John E. Sawyer, Emerson D. Nafziger

Proceedings of the Integrated Crop Management Conference

Nitrogen fertilizer is one of the largest input costs for growing corn. Across the Corn Belt, N is typically the most yield-limiting nutrient. Facing record high N fertilizer prices and potential supply problems, producers are concerned about N fertilization rates. Soil fertility researchers and extension specialists from seven states across the Corn Belt (see list in acknowledgements section) have been discussing corn N fertilization needs and evaluating N rate recommendation systems for approximately the past two years. These discussions could not have been timelier considering the current N fertilizer issues.


Update 2005 On Herbicide Resistant Weeds And Weed Population Shifts, Micheal D. K. Owen Dec 2005

Update 2005 On Herbicide Resistant Weeds And Weed Population Shifts, Micheal D. K. Owen

Proceedings of the Integrated Crop Management Conference

Given that +90% of the soybeans in Iowa are glyphosate-resistant varieties with the concomitant use of glyphosate products, and that recent interest in glyphosate-resistant corn is likely to resultin an increasing number of crop acres where glyphosate will follow glyphosate, it is important to understand the level of selection pressure from this weed management plan that will be imposed upon the weed community. Changes in agroecosystems attributable to glyphosate-based systems are already being observed. Notably, recent announcements of glyphosate-resistant weeds suggest that weed populations are reacting to the selection pressure more quickly than anticipated. Local changes include problems with common ...


Aflatoxins And Other Mycotoxins: What's In Their Future?, Gary P. Munkvold Dec 2005

Aflatoxins And Other Mycotoxins: What's In Their Future?, Gary P. Munkvold

Proceedings of the Integrated Crop Management Conference

As drought struck corn fields through much of southeastern Iowa in 2005, producers were reminded that mycotoxin problems, especially aflatoxins, often follow drought stress. Aflatoxins (produced by the fungi Aspergillus flavus and A. parasiticus) are a chronic problem for corn producers in some areas of the U.S., such as the Texas panhandle and much of the southeastern U.S. In Iowa, widespread aflatoxin problems occurred in 1983 and 1988, but since then there has not been a severe year for aflatoxins across the state. However, parts of Iowa have seen unacceptable levels of aflatoxins several times since 1988, including ...


Corn Following Corn: Potentials And Pitfalls, Palle Pedersen Dec 2005

Corn Following Corn: Potentials And Pitfalls, Palle Pedersen

Proceedings of the Integrated Crop Management Conference

Economic, political, biological, and environmental forces are all seemingly pushing for more corn planted following corn. This is true not just in Iowa, but across the Midwest. The promise of more ethanol plants and the associated increase in demand for grain as well as potentially stover are obvious factors influencing the discussion relative to increasing corn acres and the need for more corn following corn in our cropping systems. In addition to these economic factors is the concern about the intrusion of Asian soybean rust into the Corn Belt that could potentially reduce soybean yields and increase production costs. All ...


Performance-Based Management To Improve Water Quality, John Rodecap, Chad Ingels Dec 2005

Performance-Based Management To Improve Water Quality, John Rodecap, Chad Ingels

Proceedings of the Integrated Crop Management Conference

In recent years water quality assessments and the science of water quality management have progressed much more rapidly than delivery of this information and implementation of strategies for performance-based water quality improvement. Nonpoint source water quality improvements and solutions on the broad landscape need new approaches that lead to a majority of producers in a watershed community working to manage nonpoint source contaminants and jointly developing locally acceptable environmental stewardship goals.


Soybean Cyst Nematode: Old Foe Or New Nemesis?, Greg Tylka Dec 2005

Soybean Cyst Nematode: Old Foe Or New Nemesis?, Greg Tylka

Proceedings of the Integrated Crop Management Conference

The soybean cyst nematode, Heterodera glycines, is a very widespread, persistent, and yieldreducing pest in Iowa and much of the Midwest. The nematode is estimated to be in nearly 75% of the fields in Iowa (Workneh et al., I999), and eggs within cysts (dead females) can remain viable for 10 or more years without a host crop (Inagaki and Tsutsumi, 1971). Yield loss can occur without obvious aboveground symptoms occurring (Wang et al., 2003). Until 2005, it had been several years since widespread, devastating losses from SCN had occurred in Iowa. But this year, severe damage and yield loss from ...


Early Planting Of Soybean Is A Must For High Soybean Yields, Roger W. Elmore Dec 2005

Early Planting Of Soybean Is A Must For High Soybean Yields, Roger W. Elmore

Proceedings of the Integrated Crop Management Conference

Soybean varieties have a genetic yield potential greater than 100 bu per acre. However this yield potential is never reached under field conditions. Environmental conditions are usually never adequate to fully "unlock" the full genetic potential of a variety. The interaction between genetics and environment and how that translates into yield is largely unknown. Yet there are fundamental management decisions that give the best opportunity to maintain high yield. Understanding how a soybean plant develops through the season will provide insight into selection of management decisions that should lead to maintaining the yield potential. After variety selection, planting date is ...


Mmps, Nmps, Cnmps And Npdes Permits: The Alphabet Soup Of Nutrient Management Planning, Angela Rieck-Hinz, Steven Brinkman Dec 2005

Mmps, Nmps, Cnmps And Npdes Permits: The Alphabet Soup Of Nutrient Management Planning, Angela Rieck-Hinz, Steven Brinkman

Proceedings of the Integrated Crop Management Conference

Nutrient management planning in Iowa can be a complex process. The degree of planning is dependent on the need for one or more different types of management plans to serve the different requirements of state and federal agencies. Producers, their technical advisors, and agency staff are often confused as to what regulations must be met and what practices must be employed to meet the various planning processes of state and federal agencies. The objective of this paper is to review the state and federal requirements, the terminology and the current programs involving the alphabet soup of Manure Management Plans (MMPs ...


High Risk Production Years, Elwynn Taylor Dec 2005

High Risk Production Years, Elwynn Taylor

Proceedings of the Integrated Crop Management Conference

There is some indication that years of high risk for crop production tend to cluster. During the past 100 years there were 17 serious (widespread) droughts in the U.S. Com Belt. It is not uncommon to have 12 to 18 years between major drought events. During the past 200 years, the "drought cycle" has averaged about 18.5 years, but it is not clear that there is a primary weather cycle of this length. It may be that the average results from the periodic coming into phase of more fundamental climate cycles associated with events such as the Pacific ...


Cover Crop Selection And Management For Agronomic Farming Systems, Jeremy W. Singer, Tom C. Kaspar Dec 2005

Cover Crop Selection And Management For Agronomic Farming Systems, Jeremy W. Singer, Tom C. Kaspar

Proceedings of the Integrated Crop Management Conference

Cover crops can extend the season of active nutrient uptake and living soil cover and thereby reduce nutrient losses in water and sediment. The conversion of the prairies or other native vegetation ecosystems to summer annual grain crops resulted in a shortening of the season of living plant cover and nutrient uptake. Summer annual grain crops, like corn and soybean, accumulate water and nutrients and provide living cover for only about four months (mid-May to mid-September), whereas in natural systems, some living plants are actively accumulating nutrients and water whenever the ground is not frozen (at least 7 months; April-October ...


Potassium Fertilization Guidelines In Iowa: Are They Working And Should Applications Be Adjusted With High Fertilizer Prices?, Antonio P. Mallarino, Pedro A. Barbagelata, David J. Wittry Dec 2005

Potassium Fertilization Guidelines In Iowa: Are They Working And Should Applications Be Adjusted With High Fertilizer Prices?, Antonio P. Mallarino, Pedro A. Barbagelata, David J. Wittry

Proceedings of the Integrated Crop Management Conference

Iowa State University (ISU) researchers have conducted much research over time with help from Iowa farmers, crop consultants, and agribusiness to study potassium (K) fertilization of crops and use of soil-test K as a tool to determine crop K needs. Results of this research are reflected on current fertilizer recommendations, which are explained in the ISU Extension publications Pm-1688 and Pm-1310. The research continues to keep pace with changes of production practices, new hybrids and varieties, and new questions. This year Iowa farmers are looking very carefully at fertilization practices because recent sharp increases in fertilizer and fuel prices have ...


Conservation Systems Role In Sustaining Productivity And Soil Quality, Mahdi Al-Kaisi, Mark Licht Dec 2005

Conservation Systems Role In Sustaining Productivity And Soil Quality, Mahdi Al-Kaisi, Mark Licht

Proceedings of the Integrated Crop Management Conference

Conventional tillage can lead to significant increases in soil erosion and deterioration of soil structure, by increasing surface runoff. It is well documented that conservation systems can reduce surface runoff significantly due to crop residue cover and improved soil structure, soil water infiltration, and soil carbon content. The link between conservation systems and soil sustainability and productivity is well documented. The most demonstrated problem associated with the lack of conservation systems in Iowa and elsewhere is the reduction in water quality due to sediment and chemical transport to lakes and streams. The 2004 proposed 303(d) list includes approximately, 211 ...


Forage Testing Is Good Management, Stephen K. Barnhart Nov 2005

Forage Testing Is Good Management, Stephen K. Barnhart

Integrated Crop Management News

Hay supplies are tight for some livestock producers living in the 2005 summer drought areas. And, as normal, supplies of "dairy quality" hay and the "high quality" end of the hay used by the horse industry are likely below the level of need. As the winter hay and silage feeding season approaches, you still have time to set some feeding strategies. The nutritional needs of cattle, sheep, and horses can change greatly over the course of the winter feeding season.


Choosing An Scn-Resistant Soybean Variety: It's Not Just About Yield, Gregory L. Tylka Nov 2005

Choosing An Scn-Resistant Soybean Variety: It's Not Just About Yield, Gregory L. Tylka

Integrated Crop Management News

Resistant soybean varieties are a very effective strategy for managing the soybean cyst nematode (SCN), producing acceptable yields and suppressing reproduction of the nematode. The number of soybean varieties with genetic resistance to SCN in maturity groups I, II, and III has increased dramatically, from a few dozen in the early 1990s to more than 600 currently. Today, most soybean seed companies have SCN-resistant soybean varieties available for Iowa growers, and yield results of soybean variety trials conducted by private testing programs and universities have begun to be released in the past few weeks.


Rusle2 And Iowa P Index Workshops, Angela Rieck-Hinz, Kapil Arora Nov 2005

Rusle2 And Iowa P Index Workshops, Angela Rieck-Hinz, Kapil Arora

Integrated Crop Management News

Iowa State University and the Iowa Manure Management Action Group (IMMAG) in collaboration with the Iowa Natural Resources Conservation Service (NRCS) have scheduled two additional workshops to train service providers and producers on how to use the Revised Universal Soil Loss Equation (RUSLE2) software and its use in the Iowa Phosphorus Index for manure and nutrient management planning in Iowa.


Choosing An Scn-Resistant Soybean Variety: It’S Not Just About Yield, Greg Tylka Nov 2005

Choosing An Scn-Resistant Soybean Variety: It’S Not Just About Yield, Greg Tylka

Integrated Crop Management News

Resistant soybean varieties are a very effective strategy for managing the soybean cyst nematode (SCN), producing acceptable yields and suppressing reproduction of the nematode. The number of soybean varieties with genetic resistance to SCN in maturity groups I, II, and III has increased dramatically, from a few dozen in the early 1990s to more than 600 currently. Today, most soybean seed companies have SCN-resistant soybean varieties available for Iowa growers, and yield results of soybean variety trials conducted by private testing programs and universities have begun to be released in the past few weeks.


In Vitro Bile Acid Binding Of Flours From Oat Lines Varying In Percentage And Molecular Weight Distribution Of Β-Glucan, Sedat Sayar, Jean-Luc Jannink, Pamela J. White Nov 2005

In Vitro Bile Acid Binding Of Flours From Oat Lines Varying In Percentage And Molecular Weight Distribution Of Β-Glucan, Sedat Sayar, Jean-Luc Jannink, Pamela J. White

Food Science and Human Nutrition Publications

Two experimental high β-glucan oat (Avena sativa) lines (7.64 and 8.05%) and two traditional lines (4.77 and 5.26% β-glucan) were used to evaluate the effect of β-glucan quantity and molecular weight on bile acid (BA) binding. The oat flour samples were digested by an in vitro system that simulated human digestion. No significant differences among oat type were found in the overall β-glucan, starch, and pentosan digestibilities. Considering the standard, cholestyramine, as 100% bound, the relative BA binding for the oat flour samples on a dry matter basis was in the range of 7.5−14 ...


Seedling Inoculation Screening Technique To Identify Resistance To Fusarium Solani F. Sp. Glycines A Causal Agent Of Soybean Sudden Death Syndrome, Shrishail Sharanappa Navi, Xiao-Bing Yang Nov 2005

Seedling Inoculation Screening Technique To Identify Resistance To Fusarium Solani F. Sp. Glycines A Causal Agent Of Soybean Sudden Death Syndrome, Shrishail Sharanappa Navi, Xiao-Bing Yang

Plant Pathology Presentations and Posters

Sudden death syndrome (SDS) caused by Fusarium virguliforme (FV) formerly F. solani f. sp. glycines is one of the major yield reducing diseases of soybean (Glycine max). There is concern among producers due to noticeable expansion in geographical array of SDS and the associated potential yield losses. Yield loss due to SDS in the top 10 soybean producing countries varies from 2x103 in Canada to 0x105metric tons in the United States (Wrather et al., 2001). Techniques developed earlier for SDS resistance screening were inconsistent in foliar symptoms expression. Hence, objectives of the study during 2002–2005 were ...