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New Extension Corn Production Web Site, Lori Abendroth, Roger W. Elmore Dec 2006

New Extension Corn Production Web Site, Lori Abendroth, Roger W. Elmore

Integrated Crop Management News

We've designed a new Web site for Iowa State University Extension corn production that has current and relevant management information for producing corn in Iowa. The Web site provides research-based recommendations and diagnostic tools for producers and agribusinesses. The largest section of the Web site is devoted to "Corn Management," which is broken into categories based on whether the topic addresses overarching production issues, such as cropping systems and rotations, or if the topic can be isolated to a certain time of the growing season (planting, early-season, mid-/late-season, harvest). For example, in the "Planting" category, users can find ...


A Response To Phenomenon In 2006: Multiple Ears Per Node, Roger W. Elmore, Lori Abendroth Dec 2006

A Response To Phenomenon In 2006: Multiple Ears Per Node, Roger W. Elmore, Lori Abendroth

Integrated Crop Management News

Corn hybrids from several companies expressed more than one ear at a single node from Iowa to Indiana in 2006. Multiple ears are not unexpected, but they typically occur at different nodes (as with prolific hybrids), not on the same node. This trait was expressed in different ways in Iowa. In the most extreme cases, up to eight ears occurred at a single node. Some have called these "bouquets." Ears on these plants were usually barren. In one case, a field with bouquet ears yielded 50 bu/acre.


How To Interpret Scn Soil Test Results, Gregory L. Tylka Dec 2006

How To Interpret Scn Soil Test Results, Gregory L. Tylka

Integrated Crop Management News

Soybean yield loss due to the soybean cyst nematode (SCN) occurred throughout much of Iowa in 2006. Damage from this pest was particularly noticeable in areas of the state that were very dry. There seems to be increased interest in testing for and managing SCN in Iowa this fall, and there likely has been more fields sampled for SCN this fall than in recent years. Following are some commonly asked questions and answers that illustrate things to consider when interpreting SCN soil sample results. This information is excerpted from Iowa State University Extension publication IPM 61, Interpreting SCN Soil Sample ...


Crop Performance Test Bulletins Now Available, Keven Arrowsmith Dec 2006

Crop Performance Test Bulletins Now Available, Keven Arrowsmith

Integrated Crop Management News

Results of the 2006 Iowa Crop Performance Tests for alfalfa, barley, corn, oat, soybean, triticale, and winter wheat are now available. For those wanting to download a copy of the bulletins, visit the Iowa Crop Improvement Association (ICIA) Web site or the Iowa State University (ISU) Extension Distribution Center (EDC) online store. Published bulletins may be requested by contacting ICIA at (515) 294-6921 or EDC at (515) 294-5247.


Aphids In The Air: What Is The Risk For 2007?, Wayne Ohnesorg, Matthew E. O'Neal, Marlin E. Rice Dec 2006

Aphids In The Air: What Is The Risk For 2007?, Wayne Ohnesorg, Matthew E. O'Neal, Marlin E. Rice

Integrated Crop Management News

The 2006 growing season has come to a close and with it another year's worth of experience with the soybean aphid. For many, it was a quiet, "low aphid" year with few reports of economic outbreaks within Iowa. Reflecting these low populations in the field, we observed fewer aphids within our suction traps (Figure 1) compared to the 2005 growing season when the traps collected nearly 100 times more aphids (Figure 2). For the last two years, the Iowa suction trap network (Figure 3) has been part of a larger network of suction traps located in nine states throughout ...


Determining The Extent Of Frost Damage In Maize Seed Using The Tetrazolium Test, Mindy Devries, A. Susana Goggi Dec 2006

Determining The Extent Of Frost Damage In Maize Seed Using The Tetrazolium Test, Mindy Devries, A. Susana Goggi

Agronomy Publications

Frost damage in seed corn causes a significant decrease in seed quality. The tetrazolium (TZ) test has been used to identify types of physiological damage in several plant species, including frost damage in corn. Quantifying the amount of seed damaged by frost and the consequent loss of seed vigor are important for making management decisions. The current tetrazolium test procedures provide seed viability information but do not estimate seed vigor. In our project, the tetrazolium staining procedure was modified to allow separation of viable seeds into vigor categories. Vigor categories were defined based on Association of Official Seed Analysts (AOSA ...


More About Early Seed Discounts, Jim R. Rouse, Roger W. Elmore, Lori Abendroth Nov 2006

More About Early Seed Discounts, Jim R. Rouse, Roger W. Elmore, Lori Abendroth

Integrated Crop Management News

We received a great deal of feedback from our article in the October 9, 2006, issue of the ICM newsletterconcerning early seed discounts. Most of it was very positive and congratulated us for tackling an issue that is important to every grower. There were also a few readers who felt the article missed the mark, so we want to clarify some of the points.


Scn-Resistant Soybean Varieties For 2007: Many Choices, Few Sources Of Resistance, Gregory L. Tylka Nov 2006

Scn-Resistant Soybean Varieties For 2007: Many Choices, Few Sources Of Resistance, Gregory L. Tylka

Integrated Crop Management News

The soybean cyst nematode (SCN) is a major yield-limiting pest of soybeans throughout the Midwest that can be managed very effectively through use of SCN-resistant soybean varieties. Resistant varieties reduce the amount of SCN reproduction (and population density buildup) that occurs while producing significantly greater soybean yields than non-resistant (susceptible) varieties in fields infested with the nematode. The Iowa State University Extension publication titled Soybean cyst nematode-resistant soybean varieties for Iowa has recently been updated, is now available, and lists SCN-resistant soybean varieties available to Iowa growers in late maturity group 0 and maturity groups 1, 2, and 3.


Ethanol Webcast Archived Online, Jean Mcguire Nov 2006

Ethanol Webcast Archived Online, Jean Mcguire

Integrated Crop Management News

The Perspectives on Present and Future Corn-Based Ethanol Industry webcast was presented by Iowa State University (ISU) Extension on Monday, November 13. An archive of the program is available athttp://www.extension.iastate.edu/webcast/archive.htm. Seven Iowa State University economists presented economic information on several aspects of the industry during the 3-hour, 15-minute program. Links to papers offering additional information on each topic and the PowerPoint each presenter used are available at http://www.extension.iastate.edu/ag/ethanol.html.


What's Your Type?: An Hg Type Test For Scn Populations, Gregory L. Tylka Nov 2006

What's Your Type?: An Hg Type Test For Scn Populations, Gregory L. Tylka

Integrated Crop Management News

SCN-resistant soybean varieties reduce the amount of SCN reproduction that occurs when soybeans are grown. But if resistant soybean varieties are grown repeatedly, an SCN population capable of reproducing readily on the resistant varieties can develop. This is because resistant varieties are not immune; they allow some low level of SCN reproduction. The possibility of SCN populations building up on resistant varieties is especially a concern because almost all resistant soybean varieties have SCN resistance genes from the soybean breeding line PI88788 (see article on newly published list of SCN-resistant soybean varieties for 2007 in this issue).


Bt Rootworm Corn Failures: Understanding The Issues, Jon J. Tollefson, Marlin E. Rice Nov 2006

Bt Rootworm Corn Failures: Understanding The Issues, Jon J. Tollefson, Marlin E. Rice

Integrated Crop Management News

Genetically engineered corn that produces a Bt toxin effective against corn rootworms is now readily available and was widely planted in Iowa during 2006. Several seed companies have registrations, or will have shortly, and they will add additional Bt events and varieties to the choices for corn rootworm management. Does that mean that our corn rootworm management decisions are over, and we don't have to worry about rootworm injury? No. Bt corn rootworm hybrids are another insect management tool that must be thoughtfully incorporated into corn production practices.


Late Movement Of Soybean Rust, Daren S. Mueller Nov 2006

Late Movement Of Soybean Rust, Daren S. Mueller

Integrated Crop Management News

After a hot, dry summer with very little movement, soybean rust made a late push both up the East Coast and into the Ohio River Valley. After the dust settled from the excitement in October, rust was reported in 159 new counties, including seven new states (Arkansas, Illinois, Indiana, Kentucky, Missouri, Tennessee, and Virginia). Soybean rust season totals to date are 230 counties in 15 states on soybean and 262 counties total (including kudzu). Last year at this time, there were only 130 counties in seven states positive for soybean rust. No rust was found in Iowa despite extensive scouting ...


Models And Applications For Risk Assessment And Prediction Of Asian Soybean Rust Epidemics, Emerson M. Del Ponte, Cláudia V. Godoy, Marcelo G. Canteri, Erlei M. Reis, X. B. Yang Nov 2006

Models And Applications For Risk Assessment And Prediction Of Asian Soybean Rust Epidemics, Emerson M. Del Ponte, Cláudia V. Godoy, Marcelo G. Canteri, Erlei M. Reis, X. B. Yang

Plant Pathology and Microbiology Publications

Asian rust of soybean [Glycine max (L.) Merril] is one of the most important fungal diseases of this crop worldwide. The recent introduction of Phakopsora pachyrhiziSyd. & P. Syd in the Americas represents a major threat to soybean production in the main growing regions, and significant losses have already been reported. P. pachyrhizi is extremely aggressive under favorable weather conditions, causing rapid plant defoliation. Epidemiological studies, under both controlled and natural environmental conditions, have been done for several decades with the aim of elucidating factors that affect the disease cycle as a basis for disease modeling. The recent spread of ...


Icm Conference Registration Opens Soon, Brent A. Pringnitz Oct 2006

Icm Conference Registration Opens Soon, Brent A. Pringnitz

Integrated Crop Management News

The 2006 Integrated Crop Management Conference and Agribusiness Expo will be held November 29-30, 2006, at the Iowa State Center complex in Ames. The conference will once again feature a program packed with the latest information on crop production and protection brought to you by Iowa State University specialists and invited speakers from around the Midwest. Returning this year is the Agribusiness Expo, held in Hilton Coliseum on Wednesday, November 29.


Check Fields For Scn To Prepare For 2007, Gregory L. Tylka Oct 2006

Check Fields For Scn To Prepare For 2007, Gregory L. Tylka

Integrated Crop Management News

The soybean cyst nematode (SCN) continues to be an extremely damaging and widespread pest of soybean in Iowa and many other Midwestern states. The nematode infests more than 70 percent of the fields in Iowa and more than 80 percent of the fields in Illinois. Often there is no obvious stunting or yellowing of soybean plants in infested fields. Consequently, many SCN-infested fields in Iowa have not been diagnosed.


Rural And Ag Safety And Health Forum November 16, Keven Arrowsmith Oct 2006

Rural And Ag Safety And Health Forum November 16, Keven Arrowsmith

Integrated Crop Management News

Iowa's Center for Agricultural Safety and Health (I-CASH) and the Great Plains Center for Agricultural Health are cosponsoring the Midwest Rural and Agricultural Safety and Health Forum on November 16, 2006, at the Holiday Inn and Conference Center in Coralville, IA.


Grain Quality And Handling Issues For 2006, Charles R. Hurburgh Oct 2006

Grain Quality And Handling Issues For 2006, Charles R. Hurburgh

Integrated Crop Management News

The erratic rainfall patterns across Iowa have affected both yield and quality for corn and soybeans. Because more corn is likely to be stored for local use through the entire crop year, attention to harvest and storage management details will be very important.


Early Seed Discounts Don't Always Pay, Lori Abendroth, Roger W. Elmore, Jim R. Rouse Oct 2006

Early Seed Discounts Don't Always Pay, Lori Abendroth, Roger W. Elmore, Jim R. Rouse

Integrated Crop Management News

Harvest is in full swing and as we wrap up the 2006 season, many begin to plan for 2007. The 2006 growing season, though, is extremely useful when planning for next year by looking at what did or did not work. One key component is hybrid selection. Seed companies are encouraging producers to purchase 2007 hybrids early by providing cash discounts. Most companies offer the greatest discount (8 to 10%) if hybrids are selected by approximately mid-November. While this discount is a substantial amount of money, especially with increasing seed costs, you do not want to move too hastily when ...


Reminder: Fall Pesticide Training, Keven Arrowsmith Oct 2006

Reminder: Fall Pesticide Training, Keven Arrowsmith

Integrated Crop Management News

Iowa State University's Extension Pest Management and the Environment program, in cooperation with the Iowa Department of Agriculture and Land Stewardship, provides continuing instructional courses (CIC) at sites across Iowa for certified commercial applicators. Obtain a registration form on the Web atwww.extension.iastate.edu/pme or visit your local county extension office.


2006 Ag Chemical Dealer Updates, Brent A. Pringnitz Oct 2006

2006 Ag Chemical Dealer Updates, Brent A. Pringnitz

Integrated Crop Management News

Crop production changes at a rapid pace. New products, label revisions, regulatory requirements, soil nutrient recommendations--just some of the items you need to stay up-to-date on to better serve your customers. The Ag Chemical Dealer Updates are designed to do just that. The Ag Chemical Dealer Updates are intended to deliver the latest crop production recommendations, news, and information directly from Iowa State University Extension.


Soybean Stem Colonization By Genotypes A And B Of Cadophora Gregata Increases With Increasing Population Densities Of Heterodera Glycines, G. M. Tabor, G. L. Tylka, C. R. Bronson Oct 2006

Soybean Stem Colonization By Genotypes A And B Of Cadophora Gregata Increases With Increasing Population Densities Of Heterodera Glycines, G. M. Tabor, G. L. Tylka, C. R. Bronson

Plant Pathology and Microbiology Publications

Growth chamber experiments were conducted to investigate whether parasitism by increasing population densities of Heterodera glycines, the soybean cyst nematode, increases the incidence and severity of stem colonization by the aggressive genotype A and the mild genotype B of Cadophora gregata (Phialophora gregata), causal agents of brown stem rot of soybeans. Soybean genotypes with three combinations of resistance and susceptibility to H. glycines and genotype A of C. gregata were inoculated with each genotype of C. gregata alone or each genotype with two population densities of H. glycineseggs, 1,500 or 10,000 per 100 cm3 of soil ...


Trans Regulation Of Cap-Independent Translation By A Viral Subgenomic Rna, Ruizhong Shen, Aurélie Mamisoa Rakotondrafara, W. Allen Miller Oct 2006

Trans Regulation Of Cap-Independent Translation By A Viral Subgenomic Rna, Ruizhong Shen, Aurélie Mamisoa Rakotondrafara, W. Allen Miller

Plant Pathology and Microbiology Publications

Many positive-strand RNA viruses generate 3′-coterminal subgenomic mRNAs to allow translation of 5′-distal open reading frames. It is unclear how viral genomic and subgenomic mRNAs compete with each other for the cellular translation machinery. Translation of the uncapped Barley yellow dwarf virus genomic RNA (gRNA) and subgenomic RNAI (sgRNAI) is driven by the powerful cap-independent translation element (BTE) in their 3′ untranslated regions (UTRs). The BTE forms a kissing stem-loop interaction with the 5′ UTR to mediate translation initiation at the 5′ end. Here, using reporter mRNAs that mimic gRNA and SgRNA1, we show that the abundant sgRNA2 ...


Two Nematode Soil Sample Analysis Options, Gregory L. Tylka Sep 2006

Two Nematode Soil Sample Analysis Options, Gregory L. Tylka

Integrated Crop Management News

The Iowa State University Plant Disease Clinic offers two different nematode analyses for soil samples--the complete nematode count and the soybean cyst nematode (SCN) egg count. Following is a description of how the two analyses differ and when each analysis should be requested. A complete nematode count gives a count of the worm stages of plant-parasitic nematodes in a soil sample. This analysis does not give a count of the SCN eggs that may be contained in the sample.


A Roller Coaster Season, Richard O. Pope Sep 2006

A Roller Coaster Season, Richard O. Pope

Integrated Crop Management News

Like most years for Iowa farmers, 2006 was a weather roller coaster ride. The graph shows the weekly departure from 30-year average degree day accumulations from May through September. One way to read the chart is to consider a 1- to 3-week time period and look at the slope of a line at that time. If it was warmer than normal, the line rises; if cooler than normal, the line falls; and if the weather is at the average, it will neither rise nor fall.


A Step Toward Control Of Bean Pod Mottle Virus: Identifying Field Tolerance, John H. Hill, Craig Grau Sep 2006

A Step Toward Control Of Bean Pod Mottle Virus: Identifying Field Tolerance, John H. Hill, Craig Grau

Integrated Crop Management News

So, have you been wondering what to do about all those soybean plants that have mottled leaves? Populations of bean leaf beetles, the insect that efficiently transmits bean pod mottle virus, have been very high. The last issue of the ICM newsletter told you to expect potential yield reductions this fall and reduced seed quality evidenced by seeds that are stained (hilum bleeding). But there may be some soybean cultivars/accessions that are not so bad. We have known for some time that soybean cultivars can vary significantly in response to disease caused by the virus.


Cornstalk Nitrate Interpretation, John E. Sawyer Sep 2006

Cornstalk Nitrate Interpretation, John E. Sawyer

Integrated Crop Management News

So you've gotten back the results of the cornstalk nitrate samples collected this fall. Now, what do the results mean? The stalk nitrate test is based on the concentration of nitrate-N in the lower cornstalk (8-inch segment from 6 to 14 inches above the ground) when the plant reaches maturity (ISU Extension publication PM 1584, Cornstalk testing to evaluate nitrogen management). In general, as the amount of plant-available N in the soil during the time period before plant maturity increases, nitrate in the lower stalk increases. However, the stalk nitrate-N concentration can be greatly influenced by other external and ...


Corn Nitrogen Rate Calculator Web Tool Updated, John E. Sawyer Sep 2006

Corn Nitrogen Rate Calculator Web Tool Updated, John E. Sawyer

Integrated Crop Management News

Last fall the Corn Nitrogen (N) Rate Calculator Web tool went online. It is a resource that aids N-rate decisions for corn production and is helpful in determining the effect of fertilizer price on application rates. The method for calculating suggested N rates is based on a regional (Corn Belt) approach to nitrogen-rate guidelines. Details on the approach are provided in the regional publication, Concepts and Rationale for Regional Nitrogen Rate Guidelines for Corn, PM 2015. Background information and interpretation of suggested N-rate guidelines were previously provided in an ICM newsletter article.


Soybean Cyst Nematode May Cause Soybeans To Mature Early, Gregory L. Tylka Sep 2006

Soybean Cyst Nematode May Cause Soybeans To Mature Early, Gregory L. Tylka

Integrated Crop Management News

Soybean cyst nematode (SCN) is a widespread and serious pest of soybeans in Iowa. But the nematode often does not cause obvious above-ground symptoms, at least not until population densities become extremely high. One fairly consistent, albeit somewhat indirect, symptom of SCN parasitism that is apparent at this time of the year is early senescence of the soybeans. The early senescence of soybean caused by SCN is illustrated in the diagram on page 227. The squares in the map in the diagram represent 3-foot by 3-foot (9 ft2) square areas of the field. Three 1-inch diameter, 8-inch deep soil cores ...


Harvesting Lodged Corn, H. Mark Hanna Sep 2006

Harvesting Lodged Corn, H. Mark Hanna

Integrated Crop Management News

Nearly every year, adverse weather and crop conditions result in lodged corn in a few fields in the state. Lodging may be caused by wind storm, stalk rot or other disease, rootworm activity, or some combination of these. Regardless, it is a frustrating situation. Combine operators need to accept that harvest will not be routine in these areas and recognize that extra time will be required.


Sudden Death Syndrome Prevalent This Summer, X. B. Yang Sep 2006

Sudden Death Syndrome Prevalent This Summer, X. B. Yang

Integrated Crop Management News

As the summer ended, sudden death syndrome (SDS) of soybean has been found in many fields in Iowa. Widespread infestation has been reported by producers and agronomists in eastern and central Iowa, and the disease also has been found in western Iowa. This year, the disease showed up in early July with many reports before the first week of July. Cooler temperatures this summer may have contributed to its occurrence. In central Iowa, the incidence of infested fields is high, but the severity is not. In most fields where SDS is spotted, the disease occurs in small areas with limited ...