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Recommendations For Managing Soybean White Mold In 2010, Xiao-Bing Yang Dec 2009

Recommendations For Managing Soybean White Mold In 2010, Xiao-Bing Yang

Integrated Crop Management News

The 2009 growing season had record cool weather in July that was ideal for soybean white mold occurrence. The disease was widespread in the north central region of the U.S. and agronomists even in southern Iowa observed this disease in many soybean fields. In northern Iowa, patches of soybean killed by this disease were obvious in many soybean fields along the highways. Some farmers reported losses totaling more than $10,000 from this disease.


Minimize Sds And White Mold Risk To Same Field, Xiao-Bing Yang Dec 2009

Minimize Sds And White Mold Risk To Same Field, Xiao-Bing Yang

Integrated Crop Management News

Both soybean sudden death syndrome (SDS) and white mold (WM) were wide spread in Iowa during the 2009 season. The simultaneous outbreak of soybean sudden death syndrome and white mold (SDS-WM) had only occurred once previously – in east central Iowa during the 2007 growing season. This season was the first time that the two diseases were wide spread in Iowa. Many growers experienced the occurrence of SDS-WM on the same farm, some in the same field. In one session at the Iowa State University Integrated Crop Management Conference on Dec. 3 in Ames, I polled the group to learn how ...


How Delayed Harvest Might Affect Ear Rots And Mycotoxin Contamination, Alison E. Robertson, Gary P. Munkvold Oct 2009

How Delayed Harvest Might Affect Ear Rots And Mycotoxin Contamination, Alison E. Robertson, Gary P. Munkvold

Integrated Crop Management News

The corn harvest is later than it has been any time in recent memory, and the prolonged moist conditions are conducive for molds to develop on grain in the field. Over the past few days we have received numerous reports of ear rots developing in the field and questions concerning mycotoxin production when conditions are cool but wet.


2009 Corn Quality Issues – Field Molds, Alison E. Robertson, Roger Elmore, Charles R. Hurburgh Oct 2009

2009 Corn Quality Issues – Field Molds, Alison E. Robertson, Roger Elmore, Charles R. Hurburgh

Integrated Crop Management News

Frost Oct. 10 and 11 ended the crop growing season in most parts of the state, at the same time the USDA announced October yield estimates of 186 bushels per acre in Iowa. Although high grain yields are expected, reports of quality issues are surfacing.


Stalk And Ear Rots Prevalent In Iowa, Alison E. Robertson Oct 2009

Stalk And Ear Rots Prevalent In Iowa, Alison E. Robertson

Integrated Crop Management News

The cool, wet growing season has favored infection and the development of certain corn ear and stalk rots in Iowa. Foliar diseases that occurred earlier in the growing season may have increased the risk of stalk rots in fields. In corn trials across the state, anthracnose and Gibberella stalk rots are common. Ear rots that are being reported across the state include Diplodia, Gibberella and Fusarium.


Update On Hail Damaged Grain, Charles R. Hurburgh, Alison E. Robertson Sep 2009

Update On Hail Damaged Grain, Charles R. Hurburgh, Alison E. Robertson

Integrated Crop Management News

The situation with the hail damage to crops in north central Iowa is becoming clearer. On Aug. 9, 2009 an intense storm travelled approximately 150 miles from western Sac and Ida counties to eastern Grundy County. The hail swath was about ten miles wide, between Highways I-175 and US-20, with three miles in the middle being almost completely lost. The stones were large, which created major damage to both plants and developing grain. Earlier storms in northeast Iowa also created large losses but the grain itself was less developed.


Degree Days - The Finish Line Looms, Richard O. Pope Sep 2009

Degree Days - The Finish Line Looms, Richard O. Pope

Integrated Crop Management News

As of Sept. 27, 2009, we are close to winning the race between early frost and crop maturation across Iowa. The average date of first killing frost ranges from around Oct. 5 in central Iowa; about a week earlier to the north and west ,and a week later in southeast Iowa. It appears now that the 2009 first killing frost will occur at least at the average, and hopefully a bit later.


Degree Days - Watching, Waiting And Staying Warm, Richard O. Pope Sep 2009

Degree Days - Watching, Waiting And Staying Warm, Richard O. Pope

Integrated Crop Management News

A near-perfect week! Sept.13 - 20 provided seasonally normal temperatures, bright sunshine and some light rain at week's end; all of which are favorable to Iowa's maturing crop. As of Sept. 21, the mid-range forecast is calling for night temperatures that should NOT approach killing temperatures. If this bears out, it will mean no early frost in 2009.


Manage Soybean Diseases At Harvest Time, Xiao-Bing Yang Sep 2009

Manage Soybean Diseases At Harvest Time, Xiao-Bing Yang

Integrated Crop Management News

Two soybean diseases - sudden death syndrome (SDS) and soybean white mold - are wide spread in Iowa this season. In August SDS showed up in almost every Iowa region, with some regions having high disease intensity. Large patches of soybean with SDS symptom are obvious from south to north. White mold, a disease that can drastically cut yields, started to get the attention of producers in late August. This year white mold is so wide spread that agronomists report observing it in many soybean fields in southern Iowa. In northern Iowa, patches of soybean killed by this disease were so abundant ...


Hail Damage – Grain Quality Survey, Bill Arndorfer, Alison E. Robertson, Gary P. Munkvold, Charles R. Hurburgh, Steve Ensley Sep 2009

Hail Damage – Grain Quality Survey, Bill Arndorfer, Alison E. Robertson, Gary P. Munkvold, Charles R. Hurburgh, Steve Ensley

Integrated Crop Management News

There were two major hail events this summer during grain fill that resulted in significant corn crop damage in the path of the storm. The damage occurred over several thousand acres with some fields being a total loss and other fields having varying degrees of damage. This resulted in several crop hail damage meetings across the state to help farmers make informed harvest decisions. A common question from farmers and grain merchandisers dealt with grain quality issues. Specifically, what impact will the hail damage have on grain quality, ear rot severity and mycotoxin contamination in my corn crop?


Quality Issues Related To Hail Damaged Crops, Charles R. Hurburgh, Alison E. Robertson, Gary P. Munkvold Sep 2009

Quality Issues Related To Hail Damaged Crops, Charles R. Hurburgh, Alison E. Robertson, Gary P. Munkvold

Integrated Crop Management News

The August 23 hailstorm across north central Iowa, and to a lesser extent the earlier northeast Iowa storm, caught crops approaching maturity. The sheer size of the north central event, almost 200 miles long and 10 miles wide, assures that damaged grain will reach the market. Fortunately, weather since the storm has been very favorable for hastening maturity and minimizing mold toxin potential.


Degree Days - Crops In The Cooler Again, Richard O. Pope Aug 2009

Degree Days - Crops In The Cooler Again, Richard O. Pope

Integrated Crop Management News

After three weeks of near-normal temperatures, Iowa weather wrapped up August with a return to colder-than-normal. For the week of Aug. 24 - 31, we gained on average 50 degree days fewer than normal. So where does that put us?


Risk Of Mycotoxins Associated With Hail Damaged Corn, Alison E. Robertson, Gary P. Munkvold Aug 2009

Risk Of Mycotoxins Associated With Hail Damaged Corn, Alison E. Robertson, Gary P. Munkvold

Integrated Crop Management News

Hail storms that occurred recently across the state have caused considerable damage to corn crops that will likely result in reduced yields. Bruises on stalks and ear husks may allow pathogen entrance that could result in stalk and ear rots, and consequently stalk and grain quality issues. In particular, there may be increased risk of mycotoxin contamination on grain.


Goss’S Wilt And Northern Corn Leaf Blight Showing Up In Iowa, Alison E. Robertson Aug 2009

Goss’S Wilt And Northern Corn Leaf Blight Showing Up In Iowa, Alison E. Robertson

Integrated Crop Management News

This past week I have received several more reports of Goss’s wilt. Reports of the disease come from south of Highway 3, North of I-80 and east of I-35. For the most part, it seems that the disease is occurring in random fields; however this past week I visited a 200 acre field in Boone County in which many of the plants were infected. Many of the plants had extensive leaf blight occurring on the top two to three leaves of the canopy (Figure 1). Most of the lesions occurred around holes made by hail.


Degree Days - Cool July With Good Crop Conditions, Richard O. Pope Aug 2009

Degree Days - Cool July With Good Crop Conditions, Richard O. Pope

Integrated Crop Management News

Iowa corn is tasselling and silking this week. We think of the silk date as a marker for the final 60 to 65 days in which the corn reaches physiological maturity. That means we might expect dry down to extend into October across the state. Soybeans are setting pods, and with timely August rainfall, pods should fill nicely. Last week we lost approxiamtely 50 degree days to average across Iowa, making July 2009 as one of the ten coolest in history.


The 2009 Season In Degree Days Through Late August, Richard O. Pope, S. Elwynn Taylor Aug 2009

The 2009 Season In Degree Days Through Late August, Richard O. Pope, S. Elwynn Taylor

Integrated Crop Management News

Degree days are a critical driver of crop development, and 2009 certainly illustrates that point. Wet soils and cool early season temperatures delayed some plantings and also delayed the development of crops that were planted on time. The early vegetative stages were slowed by cooler-than-normal temperatures, then July arrived with a remarkably un-summerlike chill that lasted the whole month.


Degree Days - Entering The Stretch, Aiming For The Finish Line, Richard O. Pope Aug 2009

Degree Days - Entering The Stretch, Aiming For The Finish Line, Richard O. Pope

Integrated Crop Management News

Another week of cool but not too cold weather has positioned the Iowa grain crop well for the final run to harvest. During the week of August 17 we lost a net 50 to 60 degree days to average, but favorable night temperatures allowed for crop condition to improve slightly. The August 24 USDA crop condition report assesses Iowa corn and soybean both at 79 percent good to excellent. Another two or three weeks of good weather and we will begin the final dry-down push to harvest.


Degree Days – Steady As She Goes, Richard O. Pope Aug 2009

Degree Days – Steady As She Goes, Richard O. Pope

Integrated Crop Management News

Another August week down and it was again a favorable week with nearly normal temperatures. What we need most now is to avoid extremes in temperatures throughout the next month, with periodic rainfall. Last week was actually the first in nearly two months that was, albeit slightly, above normal in heat accumulation.


More On Soybean White Mold This Year, Xiao-Bing Yang, Shrishail S. Navi Aug 2009

More On Soybean White Mold This Year, Xiao-Bing Yang, Shrishail S. Navi

Integrated Crop Management News

Soybean white mold has been a production problem for soybean producers since early 1990s. White mold outbreaks often occur in even years due to crop rotations, with rare severe occurrences in odd years. Iowa’s cool, wet summer has increased the white mold risk for some growers in eastern Iowa – even though it is an odd year. Extension field agronomist Virgil Schmitt first reported the occurrence of white mold in east central Iowa and Jim Fawcett, northeast Iowa field agronomist, has received a report of severe white mold in a 60-acre field.


Managing White Mold At This Stage Of Development, Virgil L. Schmitt, Daren S. Mueller Aug 2009

Managing White Mold At This Stage Of Development, Virgil L. Schmitt, Daren S. Mueller

Integrated Crop Management News

White mold has become evident in soybeans during the last two weeks, especially in eastern Iowa. Although infection occurred shortly after the beginning of flowering in late June and early July, the characteristic white myecial growth on infected plants has only become apparent the past two weeks. Really the only good news about this disease is that it does not have too much of a secondary disease cycle. In other words the disease itself is no longer spreading or is spreading one plant at a time.


Degree Days - Average Is A Good Thing, Richard O. Pope Aug 2009

Degree Days - Average Is A Good Thing, Richard O. Pope

Integrated Crop Management News

A nearly average week of heat and some rain to boot! August could not have started better for Iowans, except for the band of hail and wind damage along the U.S. 20 / Iowa 175 corridor. For the week, we only lost around 10 to 15 base-50F degree days to average across Iowa. Like they say, just what the doctor ordered (except for the hail!). Statewide, corn development ranges from brown silk (R2) to dough stage (R3), and soybeans are busily filling pods (R4--R5).


Making Fungicide Decisions On Hail Damaged Crops, Daren S. Mueller Aug 2009

Making Fungicide Decisions On Hail Damaged Crops, Daren S. Mueller

Integrated Crop Management News

During the past weekend hail storms once again wreaked havoc on corn and soybean fields across Iowa. Much like hail damage last month and last week, growers have an option to spray fungicides to protect remaining leaf tissue. We wrote an article last month walking through a fungicide decision on hail-damaged crops at that point in the growing season. Much of the information in that article remains relevant.


A Summer 2009 Update On Diseases In Iowa Soybean, Xiao-Bing Yang, Shrishail S. Navi Aug 2009

A Summer 2009 Update On Diseases In Iowa Soybean, Xiao-Bing Yang, Shrishail S. Navi

Integrated Crop Management News

The association of plant disease with extreme weather is well documented, so it is no surprise that this year’s extreme weather with record cool temperatures and plenty of rain has created favorable conditions for disease development in soybean. Disease that we are seeing includes sudden death syndrome (SDS) and several soybean foliar diseases, the most prevalent are Cercospora leaf blight, soybean brown spot, bacterial blight, and downy mildew. As August temperatures begin to heat up diseases such as Cercospora and frogeye leaf spot can increase. This will create a mixed bag of cool and warm diseases that can cause ...


Degree Days - We Don't Need Stress!, Richard O. Pope Aug 2009

Degree Days - We Don't Need Stress!, Richard O. Pope

Integrated Crop Management News

It is beyond time to get hot summer weather started! Both corn and soybean are (finally) in reproductive stages, and parts of Iowa are over 200 degree days behind normal. But we don't want to make up that deficit with significantly above-normal temperatures, as high August temperatures mean stress that can cut yield potential dramatically. In 1992, we were nearly as far behind as now, and the cool August weather then produced an above-normal yielding crop, however the grain was wet and fall grain handling and dry down were significant issues.


Common Corn Nematode Characteristics, Gregory L. Tylka Aug 2009

Common Corn Nematode Characteristics, Gregory L. Tylka

Integrated Crop Management News

Awareness of and interest in corn nematodes seems to be growing along with the crops this season. Growers and agronomists are asking lots of good questions about how nematodes feed on corn, what soils they prefer, how much corn yield loss they cause, etc. Answers to those questions can be confusing and frustrating because there are more than a dozen different types of corn nematodes and the different species vary in their biology and behavior. The table below lists the basic characteristics of different types of corn nematodes.


Check Scn Resistant Soybean Roots For Scn Females, Gregory L. Tylka Jul 2009

Check Scn Resistant Soybean Roots For Scn Females, Gregory L. Tylka

Integrated Crop Management News

There is some concern in Iowa these days about how well SCN-resistant soybean varieties are controlling the nematode. Reports of soybean cyst nematode reproduction on resistant soybean varieties with the common source of SCN resistance, PI 88788, have increased in recent years.


Notes On Soybean Foliar Fungicide Applications In A Cool, Wet Year, Xiao-Bing Yang Jul 2009

Notes On Soybean Foliar Fungicide Applications In A Cool, Wet Year, Xiao-Bing Yang

Integrated Crop Management News

Last week I wrote an article on scouting soybean foliar diseases in this unusual summer, which has been cool and wet. As the weather trend of cool and wet continues, there are questions about the use of soybean fungicides to manage the risk of soybean foliar diseases. Now plants in many soybean fields are approaching the R3 growth stage which is critical to the effective use of foliar fungicide sprays. This report addresses a few questions on fungicide applications.


Further Considerations For Foliar Fungicides On Corn And Soybean, Daren S. Mueller, Alison E. Robertson Jul 2009

Further Considerations For Foliar Fungicides On Corn And Soybean, Daren S. Mueller, Alison E. Robertson

Integrated Crop Management News

We continue to receive e-mails and phone calls regarding the use of foliar fungicides on corn and soybean. Grain prices are down, fungicide prices are up, and this growing season, economics is likely playing a bigger role in the decision to apply a fungicide to either corn or soybean. We would like to bring up a couple more considerations for the decision making process, and also reiterate a couple of points made in previous articles.


Crops Put In A 4-Day Work Week, Richard O. Pope Jul 2009

Crops Put In A 4-Day Work Week, Richard O. Pope

Integrated Crop Management News

For organisms, heat drives development. If you can regulate your own heat like we humans do every day is a balmy 98.6 or so, so development every day is the same and can be measured by the calendar. But for our field crops and most of the pests they face, development is based on the heat they get from the environment. And, less heat means slower growth. For the week of July 12--19 alone, Iowa normally accumulates 200 base-50 degree days as a statewide average. Last week that accumulation was 133, or about four and a half "normal" days ...


Eyespot And Gray Leaf Spot Severity Continue To Increase In Iowa, Alison E. Robertson Jul 2009

Eyespot And Gray Leaf Spot Severity Continue To Increase In Iowa, Alison E. Robertson

Integrated Crop Management News

Gray leaf spot (GLS) has reached threshold levels in some corn fields in southwestern Iowa and a fungicide application should be considered for these fields. As many as 5-20 gray leaf spot lesions are present on the ear leaf and, in some fields GLS lesions are also present on the leaf above the ear leaf. Approximately one in two plants are infected, and corn is at growth stage VT/R1. A couple of weeks ago, I summarized data from Greg Shaner at Purdue University, that showed fungicide applications can be profitable when disease pressure is high and the infected hybrid ...