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Ohio State University Extension


C.O.R.N. Newsletter 2004-39

Dates Covered: 
November 22, 2004 - December 8, 2004
Harold Watters

Soybean rust has been found in the US, but will it survive?

Authors: Anne Dorrance

Asian soybean rust finally reached continental US shores in one of the hurricanes late this past summer. It has been identified now in soybean fields in Florida, Georgia, Louisiana, Mississippi and surveys are in progress in the US and Caribbean to see how widespread soybean rust is and how many points of introduction there were. This will be very interesting, but also intriguing, those storms arrived in September, but rust was not detected until early November. Most soybeans in that area have been harvested and they are surveying kudzu and the few remaining soybean fields. Data from South Africa, Paraguay and Brazil, indicate that rust can be managed with 1 to 2 fungicide applications. In most regions the first application is applied at some point during the flowering period. Even though rust has been found far south of here, the answer to the question for Ohio producers about spraying fungicide during 2005 are the words might, maybe, possibly and depends. What we still don’t know are the following:

1. Will soybean rust overwinter in the gulf region? If this is killed out by a very cold winter, we will have to wait for the next hurricane or storm to bring it back into the US. Models from Iowa State predict that it could overwinter in southern Florida and southern Texas. Surveys in those areas next spring will tell if rust will survive.

2. If we are unlucky and it overwinters, when in the spring will those infections begin to form new spores to begin the movement north is the next piece to the puzzle. The when and how fast and on which storm will determine if and when we recommend fungicide applications.

3. What will the final list of EPA approved fungicides be by next spring? We have applied for 6 fungicides for use on soybean rust in Ohio. We are in the process of applying for an additional 4 materials. EPA (as of Friday) will not consider additional materials until the first 6 have gone through the process. This will be a changing dynamic over the winter and until the dust settles we will not have a good idea of what our choices will be. Depending on what materials are available, will determine our spray timings.

How to prepare for this pathogen. There are several things that you can do on your farm to prepare for soybean rust. The first is don’t worry. This is another pathogen or headache, but it is manageable. Our goal is to limit losses as much as possible and that includes not spending money that you don’t have to.

1. Your first priority is to make the best possible selection of varieties for your field situations for 2005. Eliminate un-necessary losses to other pathogens by choosing the best variety with the best resistance package. It is pointless to have rust come in and take that yield hit when you’ve already lost yield to other diseases such as Phytophthora, SCN and Sclerotinia. For Phytophthora, choose a variety with Rps1c, Rps1k, Rps3a, a combination PLUS high levels of partial resistance. For SCN, only use SCN resistance in fields with SCN populations around 2,000 eggs/cup of soil and rotate your fields.

2. Based on predictions, it looks like Ohio may have to spray for Aphids. In this event, consider planting your fields with tram lines or skip rows for spray equipment to move through fields at these later growth stages. This will help if rust does move north and we have to spray – we won’t be driving over beans 3 and 4 times during the growing season. It will also provide good spots to scout fields.

4. Learn the different growth stages of soybeans. Spray timing for many of these pests will be set by growth stages. If this rust does not arrive until after the R5 – we will not need to spray. Yield losses are minimal at later growth stages in all grain crops and it doesn’t pay to spray at these later times. We also have preharvest intervals to consider for many materials and we do not want beans sitting in fields any longer than necessary.

5. Learn to recognize soybean rust. There is a multitude of resources out there right now. A rust ID card will be in your county office in 2 weeks time. We will be covering this topic in depth at the OSU Agronomy Teams Crop Profit Game on February 15th. Your local county extension office will be the site for this satellite program.

6. You do not need to buy fungicides at this point. EPA is still reviewing many of the materials that were applied for Section 18 labeling. Many of these have higher efficacy and are more economical than some of the materials that are currently labeled. According to the chemical companies, they will move fungicides into regions as the disease begins to move. If it is controlled where it begins, that reduces the overall inoculum and slows the epidemic down to where we, and many northern states, may not have to spray on an annual basis. If this pathogen stays here in the US.

There are still a lot of unknowns, but fortunately for us, this came in November and we have the winter to solidify plans that were already in development and begin the education progress. Fungicides may or may not become part of our annual soybean production practice, but the keys to keeping this venture profitable:
• recognize when soybean rust is in the region,
• proper timing of materials and if they are economical to apply,
• proper choice of materials for the infection stage,
• thorough coverage of fungicides on the crop and targeting those low leaves in the canopy,
• Manage everything else to limit losses.

Another Year with Record Corn Yields: The 2004 Growing Season in Perspective

Authors: Peter Thomison, Patrick Lipps, Robert Mullen

As the 2004 harvest nears completion, record corn yields are predicted across the Corn Belt. According to the October crop report, USDA estimates that Ohio corn yields will average 160 Bu/A in 2004, 4 bushels more than last year’s record yield of 156 bu/A. Record corn yields are also projected for other states, including Iowa and Illinois (with yields averaging 183 and 180 bu/A, respectively) and Indiana (with yields averaging 169 bu/A).

How did we achieve such high corn yields? Although there was considerable variability in rainfall across the state, the 2004 growing season was characterized by cooler and wetter than normal. These conditions resulted in record and near record yields on many farms in Ohio. Past studies of climate effects on crop yield have shown that cooler and wetter than normal conditions during July and August are ideal for producing high corn yields.

The following are some key factors responsible for the high yields.

1. Timely planting: Over half the corn crop was planted by May 2. This was slightly ahead of the five year average. Past OSU research indicates that planting in late April through early May usually results in the highest yields.

2. Good seedbed conditions: In the weeks preceding planting, rainfall and temperature were near normal. Soil conditions allowed timely field operations and minimized soil compaction.

3. Favorable conditions for emergence and early growth. Soil conditions for most plantings in April were excellent and promoted uniform emergence and good stands. Moderate temperatures and rainfall were favorable for growth. According to USDA estimates by May 16, 50% of corn plants had emerged, one day ahead of the 1999-03 average.

4. Crop growth was not limited by a lack of soil moisture. In most areas, rainfall was above average throughout much of the growing season. Soil moisture was generally sufficient throughout the season because of frequent rains and/or cooler than normal temperatures (see below).

5. Cooler than average temperatures minimized stress. During most of the growing season, temperatures were below normal. From late June through most of August, a period of time that included most of the grain fill period, weekly temperatures were cooler than normal - as much as 4 to 7 degrees below normal in August. High night temperatures (in the 80s or above) result in wasteful respiration and a lower amount of dry matter accumulation in the plant. In 2004, cool night temperatures reduced respiration losses during grain fill. The absence of moisture stress is especially important during grain filling (the period from silking to physiological maturity or black layer formation). In parts of Ohio where rainfall was below average during grain fill in July and August, cooler than average temperatures minimized moisture stress. Cooler than normal temperatures may have also reduced soil nitrogen losses that can occur under warm, saturated soil conditions through denitrification.

6. An extended grain fill period. Corn growth was well ahead of normal in many Ohio corn fields. Tasselling and silking were evident in some April planted fields by late June and early July. We don’t usually expect to reach this stage of development until mid July. In 2004, corn silking was approximately 67 percent completed by June 18, 10 days ahead of 2003, and nine days ahead of the five-year average. This earlier than normal silking combined with a cooler than normal August may have increased the length of the grain fill period in 2004, thereby contributing to higher grain yields.

7. No major harvest delays. Although July and August were cooler than normal, warmer than average temperatures during September helped corn planted in April and May to achieve maturity before the first major frosts on Oct. 3 and 4. Grain moisture at harvest was lower than many growers expected. Stalk lodging problems were localized and did not cause major harvest delays.

8. No major pest problems. Despite above average rainfall in many areas, conditions favorable for disease - extended periods of high humidity and warm temperatures - were generally absent. Foliar disease problems, including northern corn leaf blight and common rust, started showing up in some fields of susceptible hybrids in August. Although yield was reduced significantly in the most susceptible hybrids, the upper leaves of most hybrids did not become seriously diseased until late in the grain fill period, resulting in less impact on yield. Relatively cool and wet weather were favorable for ear rots in some areas of the state. In these areas, Gibberella ear rot and especially Diplodia ear rot, significantly reduced grain yield. Significant disease injury was generally limited to particularly susceptible hybrids. Although the level of stalk rot diseases was higher than during the preceding 5 year period, harvest advanced rapidly before significant lodging and loss of ears in the field resulted. Insect damage was limited overall, and European corn borer injury was not widespread.

9. Good management practices. The contributions of growers to the high yields of 2004 cannot be overlooked. The use of more effective and improved management practices involving nitrogen management, hybrid selection, crop establishment, and pest control also helped increase yields.

The record yield projected for Ohio might have been even higher if not for the severe weather that reduced yields or destroyed crops in parts of the state. Too much rain in April and May delayed corn planting for many growers in north central Ohio. A number of river bottom and low lying corn fields near the Ohio and Scioto rivers were destroyed by flooding from Ivan in September.

Considering the amount of lower-leaf firing that occurred many were concerned that N deficiencies were going to result in yield losses. Lower leaves in some areas were firing as early as late June. While our environmental conditions were conducive to N loss early (due to warmer than average temperatures in May and wet conditions), perhaps late-season mineralization was able to keep up with plant need (which was slowed by cooler temperatures) even though N-stress was apparent. Take that last statement with a grain of salt because many environmental conditions can result in firing of lower leaves which may be incorrectly interpreted as N stress. A longer grain filling period may have contributed to less yield loss associated with N-deficiency because root uptake of N was able to keep up with the demand of the plant.

2004 an Excellent Soybean Crop

Authors: Jim Beuerlein

The 2004 soybean crop was our best ever with a state average yield of 47 bushels per acre which is two bushels per acre more than the previous record of 45 bushels set in 1997. That 47 bushels per acre yield in 2004 is 57 percent more than the 30 bushels per acre we produced in 2002. Those huge differences are due to the direct effect weather has on the crop and also the effect the weather has on our ability to get the crop planted timely and other management operations completed in a timely manner. In 2003 we observed that the crop was able to tolerate stress in May and June. The poor growing conditions in July through September of 2003 severely limited yields (38 bushels per acre for soybeans). The weather in May and June of 2004 was also very poor, but July through September was ideal for pollination and grain production resulting in record yields.

Normally, there are three main sources of crop stress in July through September. They are poor weather, insect feeding and disease. Disease can easily reduce yields ten to ninety percent depending on which disease(s) are present and when infection happens. Insects can reduce yield by as much as fifty percent if they start feeding early and are not controlled and poor weather can reduce yield to fifty percent of normal. When two of these stresses are active at the same time their combined effect is three times greater than either one alone would be.

We can’t control the weather but we can control disease and insects through the proper use of cultural practices and pesticides. The more we can reduce crop stress, the better our yields will be. The 2004 growing season shows us that when all goes well, the soybean can produce yields of over 80 bushels per acre. We also know that most varieties have the genetic capacity to produce yields of over 100 bushels per acre. So the secret to high yields is stress elimination, pest reduction and management.

Summary, 2004 Ohio Soybean Performance Trial

Authors: Jim Beuerlein

One Hundred and Seventy five soybean varieties were evaluated in the 2004 Ohio Soybean Performance Trials conducted by The Ohio State University. There were two test sites in each of three test regions representing North, Central and Southern Ohio. Varieties from 31 companies were evaluated for yield, disease reaction, height, seed size, relative maturity, lodging, and protein and oil content. In 2004, 149 of the varieties were Roundup Ready and 22 were normal varieties. Many of the normal varieties were experimental lines. Table 1 contains the range and mean of the characteristics measured.

Table 1. The Minimum, Mean and Maximum values recorded for various characteristics and grain yield at the six test sites for the 2004 Ohio Soybean Performance Trials.

table 1

Relative Maturity
Plant Ht. (in.)
% Protein
% Oil
Phytophthora Partial Resistance
Phytophthora Resistance Genes
(151 of 175
varieties had
1 or 2 genes)
North Region

Yield at Henry Co. Site
Yield at Huron Co. Site
Central Region

Yield at Mercer Co. Site
Yield at Delaware Co. Site
South Region

Yield at Preble Co. Site
Yield at Clinton Co. Site

Variety selection should be based on three major variety characteristics: performance history, tolerance and resistance to disease, and relative maturity. The varieties that performed well last year will likely be good performers next year if the growing conditions are similar. Since every soybean field in the state is infected with disease, we need to choose varieties with resistance and/or tolerance to those diseases. If the weather and soil conditions are suitable for infection, our crop will get infected. Fungicide seed treatments should be used on all soybean seed to reduce stand loss due to root rot disease and to improve the health of the root system and thus yield loss due to root rot diseases. The yield increases due to seed treatment is usually worth about three times more than the cost of the seed treatment. Selecting a wide range of maturities will reduce losses due to adverse weather, allow for more timely harvest, increased grain quality and reduced harvest-time stress. Plant the short-season varieties first and the late varieties last. Both early planting and narrow rows increase yield. Seeding rates on dark colored soil should be 150,000 to 175,000 seeds per acre. Seeding rates on light colored soil should be 175,000 to 225,000 seeds per acre.

Data from the Ohio Soybean Performance Trials, the Ohio Corn Performance Trials, and the Ohio Forage Performance Trials are available on the Internet the week at: All of Ohio State University’s Performance trials are also available at

Soybean Cyst Nematode Resistant Varieties

Authors: Dennis Mills, Anne Dorrance

When the SCN populations in a field range from 200 to 2000 eggs per cup of soil a soybean cyst resistant variety can be planted. A listing of SCN resistant varieties available for 2005 can be found at

DO NOT PLANT SCN RESISTANT varieties in fields with SCN populations greater than 2,000. In most varieties only one source of resistance is present. If this source is planted into fields with high populations, you will favor those nematodes that can reproduce on that source and the nematodes will build up in a very short period of time. The end result will be a field with a high SCN population with no resistant varieties available. Additional information is available from the SCN Fact Sheet (

Not Too Late for Fall Herbicide Treatments

Authors: Mark Loux

Wet soil conditions have prevented application of fall herbicide treatments in some fields, but there is still time to do so if soil conditions permit. In OSU research, fall herbicide treatments have been effective for winter annual weed control into early December, even after the weather turned cold. We assume that herbicides can effectively control dandelions that are still about 50% green, but control of this weed is likely to be affected to a greater extent by very cold weather, compared to winter annual weeds. In a study we conducted last fall at OARDC Northwest Agricultural Research Station, we applied herbicides on September 30, October 31, or December 22 to determine the effect of application date on dandelion control. Herbicide effectiveness was similar between September 30 and October 31, when the most effective treatments controlled about 80% of the dandelion (measured in spring evaluations). Control was generally lower with the December 22 timing, for which the most effective treatments controlled about 65% of the dandelion. We consider fall herbicide treatments to be the most effective tool for reducing dandelion infestations, so consider making an herbicide treatment within the next several weeks even if the weather turns colder. One caution about herbicide applications under cold conditions – herbicides with residual activity (Canopy, simazine, Sencor) should not be applied to frozen ground.

Crop Profit Game Agronomy Information

Authors: Greg LaBarge

The first of three Crop Profit Game broadcast will be December 14th from 7-9 pm. These programs will build upon each other in sharing the latest on research information, recommendations and input concerns for Ohio row crop producers. Broadcast will be available at many Extension Offices across the state. For the location nearest to you call your local extension office or see for an interactive map or zip code search.

Presentations for the December 14th program include:

P&K Rates for Corn & Soybeans - Robert Mullen
Soybean Cyst Nematode - Anne Dorrance
Soybean Seeding Rates Research and Inoculants - Jim Beuerlein
Soybean Seed Treatments: Current Product Lines Use Rates - Anne Dorrance
Corn Seed Treatments and Technology - Ron Hammond
Rating Corn Disease Importance In Hybrid Selection - Pat Lipps

Be sure to mark your calendars for the other Crop Profit Game dates January 11th and February 15th. Agenda’s for these upcoming programs can also be found at If you have question about these programs contact Greg La Barge at 419-337-9210 or or Harold Watters at 937-440-3945 or

Year End Conferences - Ohio No Till Conference, Corn & Soybean Conference, Agronomy Day

Authors: Harold Watters

Ohio No Till Conference
This year’s Ohio No Till Conference is scheduled for Tuesday, December 7th at the Der Dutchman Restaurant in Plain City, Ohio on SR 42 south side of town. The conference is planned from 9AM to 3 PM with registration beginning at 8AM. Certified Crop Advisers can earn 4.5 continuing education credits. You are strongly encouraged to register prior to the conference for $20. Call or mail in your reservation by December 2nd for the low price. The walk in registration fee is $25. Phone Jane Aycock to make reservations at 614 255-2460.

2004 Ohio Corn and Soybean Conference
The 2004 Corn and Soybean Conference will be held Monday December 13th at the Der Dutchman Restaurant in Plain City from 7:30 AM to 3PM. Representatives will present frontline issues affecting the corn and soybean industries. Topics covered include: Soybean Rust, the Energy Bill, Ethanol and Biodiesel tax incentives, Opportunities and Challenges facing the Livestock Industry. Conference registration is $20 per person and includes a continental breakfast and lunch. To register call Carla at 614 476-3100 or Marge at 740 383-2676.

OSU Extension Agronomy College Day
This program will be held Thursday, December 16, 2004 from 9 AM - 3 PM in Founders Hall on the OSU Newark/Central Ohio Technical College Campus in Newark, OH 43055. Available are 5 hours of continuing education credit for Certified Crop Advisers (2 SW, 1 NM, 2 PM) plus one hour of 2A commercial pesticide recertification credit. Cost for the program is $35.00 and includes the meal; advance registrations are needed by December 10th. For additional information phone Howard Siegrist at 740-349-6900 or e-mail

Archive Issue Contributors: 

State Specialists: Pat Lipps, Anne Dorrance and Dennis Mills (Plant Pathology), Robert Mullen (Soil Fertility), Mark Loux and Jeff Stachler (Weed Science), Ron Hammond (Entomology), Peter Thomison (Corn Production) and Jim Beuerlein (Soybean Production). Extension Agents and Associates: Glen Arnold (Putnam), Roger Bender (Shelby), Steve Foster (Darke), Howard Siegrist (Licking), Greg Labarge (Fulton), Gary Wilson (Hancock), Dusty Sonnenberg (Henry), Barry Ward (Champaign), Mark Koenig (Sandusky), Steve Prochaska (Crawford) and Harold Watters (Miami).

Crop Observation and Recommendation Network

C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.