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Soybean Cyst Nematode Confirmed In Ida County In 2008, Gregory L. Tylka Dec 2008

Soybean Cyst Nematode Confirmed In Ida County In 2008, Gregory L. Tylka

Integrated Crop Management News

The soybean cyst nematode has been known to exist in Iowa since 1978. The first Iowa finding was in Winnebago County. In the 1980s and 1990s, SCN was found for the first time in many different Iowa counties. By 2000, SCN had not yet been found in only nine Iowa counties. By the end of 2007, it had not yet been found or officially confirmed in only three Iowa counties – Allamakee, Ida, and Lyon County. Earlier in 2008, SCN was confirmed to be present in Lyon County.


Effects Of N-Hibit™ Seed Treatment On Soybean Yields – 2008 Iowa Research, Gregory L. Tylka, Chris Marrett Dec 2008

Effects Of N-Hibit™ Seed Treatment On Soybean Yields – 2008 Iowa Research, Gregory L. Tylka, Chris Marrett

Integrated Crop Management News

Harpin protein is a natural plant compound that can stimulate plant defense responses. And N-Hibit is a seed-treatment containing harpin protein that is sold in the United States for management of the soybean cyst nematode (SCN). Iowa State University Extension evaluated the effects of N-Hibitseed treatment on soybean yield and SCN population densities in nine field experiments located throughout Iowa in 2007 and in nine different field experiments in 2008. The work was supported by the soybean checkoff through funds from the Iowa Soybean Association.


Fall Is Ideal Time To Check For Presence Of Scn, Gregory L. Tylka Dec 2008

Fall Is Ideal Time To Check For Presence Of Scn, Gregory L. Tylka

Integrated Crop Management News

The soybean cyst nematode (SCN) continues to be a serious yield-reducing pest of soybean in Iowa and throughout the Midwest. But damage from SCN is almost always less noticeable in growing seasons with adequate to excess moisture, which much of Iowa experienced in 2008. There can be 30 percent yield loss or more without the soybean crop looking noticeably damaged during the growing season. Very serious soybean yield losses due to SCN are expected the next time Iowa experiences a very dry growing season.


Soybean Rust - 2008 In Review, Daren S. Mueller Dec 2008

Soybean Rust - 2008 In Review, Daren S. Mueller

Integrated Crop Management News

While 2008 will be known for its early season rains, this did not translate into soybean rust arriving in Iowa. Soybean rust was reported in Alabama, Florida, Louisiana, Mississippi, Texas and Mexico in January. However, dry weather during early spring in southern Texas and Gulf Coast states helped keep soybean rust from building up inoculum and spreading early in the season. Since January 2008, soybean rust has been reported in 396 counties in the U.S. and Mexico, which is more than any previous year (Table 1). However, many of these finds were late in the season, more so than ...


Soil Sample Results Can Reveal If Scn Management Is Working, Gregory L. Tylka Dec 2008

Soil Sample Results Can Reveal If Scn Management Is Working, Gregory L. Tylka

Integrated Crop Management News

Fall soil sampling has been promoted for many years as an effective way to detect the soybean cyst nematode (SCN) in fields. But many Midwestern soybean producers already know which fields are infested with SCN and have been growing SCN-resistant soybean varieties for numerous years to manage SCN population densities. The key to profitable long-term soybean production in SCN-infested fields is to prevent SCN population densities (numbers) from increasing.


New Field Guide For Soybean Cyst Nematode Management Available, Richard O. Pope Nov 2008

New Field Guide For Soybean Cyst Nematode Management Available, Richard O. Pope

Integrated Crop Management News

Knowing how to recognize and manage soybean cyst nematode is the sole focus of a new pocket guide authored by Iowa State University Extension Nematologist Greg Tylka, in partnership between Iowa State University and the Iowa Soybean Association.


Use Of Fungicides To Control Soybean Foliar Diseases: A 6-Year Summary, Xiao-Bing Yang, Shrishail S. Navi, John M. Shriver, Kenneth T. Pecinovsky Nov 2008

Use Of Fungicides To Control Soybean Foliar Diseases: A 6-Year Summary, Xiao-Bing Yang, Shrishail S. Navi, John M. Shriver, Kenneth T. Pecinovsky

Integrated Crop Management News

Prior to 2005, foliar diseases were not of major concern to soybean production in Iowa and much of the north central region, except for soybean seed production. However, since the report of Asian soybean rust in South America in 2001 and then in the United States in 2004, interest in fungicide applications in soybean production has increased consistently, making use of fungicides on soybeans a hot topic.


A Weather Summary For The 2008 Growing Season, Richard O. Pope Oct 2008

A Weather Summary For The 2008 Growing Season, Richard O. Pope

Integrated Crop Management News

And in a general sense that is a good description, as the Iowa statewide accumulation of crop growth degree days was about 130 behind the 30 year average, and rainfall was more than 7 inches above normal. But when we examine each by crop reporting district through the season, the story gets a bit more complex, depending on where you are looking.


Corn Quality Issues In 2008 – Field Molds, Charles R. Hurburgh, Alison E. Robertson, Roger W. Elmore Oct 2008

Corn Quality Issues In 2008 – Field Molds, Charles R. Hurburgh, Alison E. Robertson, Roger W. Elmore

Integrated Crop Management News

Fall weather has allowed late planted corn to mature, increasing grain yields expectations - the USDA October yield estimate is 172 bushels per acre in Iowa. Although high grain yields are expected, reports of quality issues are surfacing. The cool wet fall conditions also favor the development of fusarium fungi; the white or pink ear rots that are often found in ear corn stored too wet. Field moistures in the low 20s over a long period are favorable for these fungi, which in turn can produce several toxins harmful to people and livestock – vomitoxin, zearalenone, and fumonisin. Grain with field mold ...


Corn Disease Publication Now Available, Alison E. Robertson Oct 2008

Corn Disease Publication Now Available, Alison E. Robertson

Integrated Crop Management News

Corn producers and other professionals in the agriculture industry depend on the Iowa State University Extension publication Corn Diseases, PM 596. It is always in high demand, and after a revision, is back on the shelf to be ordered from the Extension online store.


Fall Tillage Considerations For Soybean Disease Management, Xiao-Bing Yang Oct 2008

Fall Tillage Considerations For Soybean Disease Management, Xiao-Bing Yang

Integrated Crop Management News

Fall tillage operations become a consideration at harvest time, and plentiful soil moisture makes moisture conservation a non-issue. However, the management of soybean diseases could be a consideration if you have fields with severe disease problems this year.


Seed Quality At Harvest, Xiao-Bing Yang Sep 2008

Seed Quality At Harvest, Xiao-Bing Yang

Integrated Crop Management News

During the past planting season, there were many reports of low soybean seed germination rates, which may have been the result of last year’s wide spread of Phomopsis. Severe Phomopsis fungus infection can reduce seed quality. This season, several diseases (Cercospora, downy mildew, and white mold) were prevalent in different parts of Iowa; the causal fungi of these diseases can infect seeds. As harvest begins, it is time to learn about these diseases and check seed quality.


Time To Scout For Stalk And Ear Rots, Alison E. Robertson Sep 2008

Time To Scout For Stalk And Ear Rots, Alison E. Robertson

Integrated Crop Management News

When corn reaches black layer, the crop should be scouted for stalk and ear rots. Anthracnose stalk rot is apparent in many fields across the state andDiplodia ear rot has been reported. The incidence of corn ear rot should be determined before harvest since ear rot diseases can reduce yield and quality of the corn harvest. Furthermore, some of the fungi that infect corn ears may produce mycotoxins, which are harmful, and can be fatal, to livestock.


Cool And Calm, Now Hopefully We Collect!, Richard O. Pope Sep 2008

Cool And Calm, Now Hopefully We Collect!, Richard O. Pope

Integrated Crop Management News

It is September 24 and thankfully no frost to speak of yet. The 2008 season will be one to look back on as a reference for variable weather effects on crops. I last posted degree day data in mid-August. As mentioned in that article, daily degree day accumulations are less critical once corn and soybean progress to reproductive stages, when general water and temperature stresses and solar radiation drive development.


Diplodia Ear Rot Being Reported In Iowa, Alison E. Robertson, Fanny Iriarte Sep 2008

Diplodia Ear Rot Being Reported In Iowa, Alison E. Robertson, Fanny Iriarte

Integrated Crop Management News

Ear and stalk rots are likely to become prevalent in Iowa as the growing season draws to a close. In the past week, we have had a few reports of Diplodia ear rot from the northeast, central and southeastern parts of the state. This ear rot is not as common as Fusarium or Gibberella ear rot in Iowa.


Soybean Top Dieback Shows Up In Iowa Again, Xiao-Bing Yang, John E. Sawyer Aug 2008

Soybean Top Dieback Shows Up In Iowa Again, Xiao-Bing Yang, John E. Sawyer

Integrated Crop Management News

Extension field agronomists report the occurrence of soybean top dieback in northeastern Iowa soybean fields this week. Soybean top dieback symptoms have shown up occasionally since it was first reported by Jim Fawcett and Jerry Long in Cedar County a few years ago. Last year it was also found in eastern and central Iowa.


Pre-Harvest Restrictions For Fungicides, Daren S. Mueller Aug 2008

Pre-Harvest Restrictions For Fungicides, Daren S. Mueller

Integrated Crop Management News

With the buzz of airplanes still being heard out in the countryside and September within sight, this is just a quick reminder to growers about the pre-harvest intervals (PHI) for fungicides applied to corn and soybean. Last month in Kansas, some wheat was embargoed when fungicide levels were questioned until tests could be completed to determine residue levels.


Fill ‘Er Up!, Richard O. Pope Aug 2008

Fill ‘Er Up!, Richard O. Pope

Integrated Crop Management News

In a season that started with weather tumult fouling up the planting season in many areas, we have done pretty well in getting the corn and soybean to reproductive stages. Degree days remain behind long-term averages as of August 17.


Goss’S Wilt Prevalent In Western Iowa, Alison E. Robertson, Laura C.H. Jesse Aug 2008

Goss’S Wilt Prevalent In Western Iowa, Alison E. Robertson, Laura C.H. Jesse

Integrated Crop Management News

This past week several corn samples infected with Goss’s wilt were submitted to the Iowa State University Plant and Insect Diagnostic Clinic. Tamra Jackson at University of Nebraska, Lincoln has also reported an increase in the prevalence of Goss’s wilt in Nebraska this growing season (see Crop Watch, August 8, 2008).


Midsummer Scouting For Downy Mildew And Other Soybean Diseases, Xiao-Bing Yang, John Kennicker Aug 2008

Midsummer Scouting For Downy Mildew And Other Soybean Diseases, Xiao-Bing Yang, John Kennicker

Integrated Crop Management News

Summer soybean disease scouting is revealing some interesting finds due to several years of unusual weather. This is the third year in a row that Iowa has had a cool summer. The summer of 2006 was cool, but not wet; this year and last year, cool and wet.


Soybean Rust And Late Planted Soybeans, Daren S. Mueller Aug 2008

Soybean Rust And Late Planted Soybeans, Daren S. Mueller

Integrated Crop Management News

Iowa producers are asking if soybean rust will affect the late planted soybean crop. Taking a look at current U.S. locations of soybean rust and understanding the movement of the rust, helps answer the question for Iowa producers.


All Things Considered, It Could Be Worse!, Richard O. Pope Aug 2008

All Things Considered, It Could Be Worse!, Richard O. Pope

Integrated Crop Management News

Corn and soybean condition has remained remarkably good in general as we enter August. Favorable weather in the early summer certainly has not made up for the early season planting problems that plagued parts of Iowa, but it has allowed crops to recover. The last week of July was warm and allowed vegetative staged crops to make up some lost degree day ground.


Know Your Spots As Foliar Diseases Show Up In Corn, Alison E. Robertson Aug 2008

Know Your Spots As Foliar Diseases Show Up In Corn, Alison E. Robertson

Integrated Crop Management News

Several foliar diseases are being reported in corn at this time, and it is important to be able to differentiate between the various leaf spots because management options will vary. Some leaf spots are caused by bacteria and therefore cannot be managed with a foliar fungicide. Development of other leaf spots will slow considerably in the extreme hot temperatures we are currently having. However, there are some leaf spots that favor these hot, humid conditions and, depending on disease pressure and hybrid susceptibility, management with a foliar fungicide may be warranted.


Now Is The Time To Sample For Corn Nematodes, Gregory L. Tylka Aug 2008

Now Is The Time To Sample For Corn Nematodes, Gregory L. Tylka

Integrated Crop Management News

Interest in plant-parasitic nematodes as pests of corn in Iowa, and much of the Midwest, has increased dramatically in the past few years. Damage from these microscopic worms, which feed from within the roots and on the outside of roots, can cause overall stunting of the plant and yellowing of foliage. Ears may be stunted and poorly filled due to damage by this pest. Feeding by some nematode species also causes swelling of corn roots. None of these symptoms are unique and useful in identifying fields in which such damage is occurring.


Two Soybean Aphid Field Resources Now Available, Richard O. Pope Jul 2008

Two Soybean Aphid Field Resources Now Available, Richard O. Pope

Integrated Crop Management News

Knowing how to manage and "speed scout" soybean aphids, just got easier, thanks to two new pocket-sized publications authored by Iowa State University Extension entomologists Marlin Rice and Matt O'Neal. The companion soybean aphid publications are right off the press and available from ISU Extension. One is a spiral-bound "Soybean Aphid Management field guide for 2008," extension publication number CSI 11. The 43-page pocket guide is focused on management of soybean aphid in Iowa. The guide is a handy reference to the history, identification, development and management strategies for this relatively new insect pest for Iowa.


Preventative Vs. Curative Fungicides, Daren S. Mueller, Alison E. Robertson Jul 2008

Preventative Vs. Curative Fungicides, Daren S. Mueller, Alison E. Robertson

Integrated Crop Management News

We have received several questions about selection of fungicides, especially with regards to deciding between “curative” and “preventative” fungicides. People want to know if they should be applying a strobilurin fungicide, triazole fungicide, or a premix of both.


More On Fungicide Application Questions, Xiao-Bing Yang Jul 2008

More On Fungicide Application Questions, Xiao-Bing Yang

Integrated Crop Management News

Near the end of July, a common time for fungicide applications, there are many questions about using fungicides to control soybean diseases. This article responds to questions producers are currently asking about soybean and corn fungicide use.


Unusual Foliar Diseases Showing Up In Iowa Corn, Alison E. Robertson Jul 2008

Unusual Foliar Diseases Showing Up In Iowa Corn, Alison E. Robertson

Integrated Crop Management News

Over the past week I have received emails, phone calls and samples of two leaf spots that occur in Iowa from time to time, Holcus leaf spot and Physoderma brown spot. Holcus leaf spot is caused by the bacterium Pseudomonas syringae. Symptoms are light tan (sometimes almost white), round to oval spots, which may appear water soaked at the margins or have a light brown border occur on the lower leaves (Figure 1 and 2).


Not A Bad Week, All In All, Richard O. Pope Jul 2008

Not A Bad Week, All In All, Richard O. Pope

Integrated Crop Management News

The week ending July 13 was close to average in terms of temperature, and crops have generally made slow but steady improvement in condition over the period. Normal daily accumulations of degree days vary throughout the year, with July obviously being warmer than May. An average Iowa mid-July day produces about 24 base-50 degree days in the northern third, around 25 in central counties and 26 to 27 in the southern third of the state. That means that currently, we are about four to five full developmental days behind average for the season from May 1 through July 13. Of ...


Soybean Cyst Nematode Females Now Apparent On Soybean Roots, Gregory L. Tylka Jul 2008

Soybean Cyst Nematode Females Now Apparent On Soybean Roots, Gregory L. Tylka

Integrated Crop Management News

Many Iowa soybean fields may be infested with the soybean cyst nematode (SCN) but the infestations may not be known because SCN does not always cause obvious, above-ground symptoms. In fact, yield loss of up to 40 percent has been documented without above-ground symptoms occurring.