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Ohio State University Extension


C.O.R.N. Newsletter 2004-41

Dates Covered: 
December 20, 2004 - January 11, 2005
Harold Watters

2nd Crop Profit Satellite Conference January 11th

Authors: Greg LaBarge

Ohio State University Extension is on tap to offer this year’s “The Crop Profit Game,” a satellite series for Ohio crop producers, agronomy retailers and other agribusiness individuals.

The next two broadcasts, being held Jan. 11 and Feb. 15, will be hosted by ABN Radio’s Dale Minyo, and feature Ohio State University Extension specialists with the latest information in agronomic crop production. The event is designed to highlight current production practices, input recommendations and economic concerns for Ohio’s crop industry.

Topics for discussion during the broadcasts will include:

* Jan. 11: Weed control issues, corn rootworm, precision agriculture update and getting the most from your nitrogen dollar.

* Feb. 15: Soybean aphid, wheat fungicides, soybean rust, grain marketing outlook and using crop revenue coverage in developing a grain marketing plan, and evaluating harvest date and plant population effects on corn standability and final yield.

Ohio residents have three ways to view the programs. Many OSU Extension offices are making the program available. Call your local Extension office or visit for details. Options exist for those who want to view the broadcast at home via Dish Network Satellite or Internet streaming video. Cost for these at-home options are $30 in-state or $50 out-of –state for the series of broadcasts. Requirements and registration information are available at or by contacting Greg LaBarge at (419) 337-9210, or e-mail

Materials from the December 14th broadcast can be found at

Soybean Rust Update – December 20

Authors: Anne Dorrance

More questions and more developments as soybean rust continues to be a major focus of conversation over the past few weeks. I’ve gotten some great questions and issues have been raised so here is some information based on what we know today.

Overwintering, what does this mean? Rust fungi are biotrophic organisms, in that they must be associated with a living host. The rust fungus will continue to produce spores and make new infections until that plant dies. Kudzu is one of the many host plants for this fungus. However, kudzu is a southern plant and does die back every winter in the Gulf states. The next question – and there will be lots of questions over the next few years—is what host plants of soybean rust remain green in the Gulf states and for this year, did any of them become infected with soybean rust? Too early to tell this at this point – we will know some answers to this question in March.

Should I change to wider rows? My response to this is no. And these are the reasons. Extensive studies on the effect of row width on yield of soybeans have been conducted by Dr. Jim Beuerlein in the past. Additionally, we have demonstrated through numerous white mold studies paid by check-off dollars that moving from 7 and 15” rows to 30” rows reduces overall yield. If Ohio is going to remain competitive we are going to have to learn to manage rust in our high yield production systems that we currently have in place. In the white mold studies we conducted in the late 90’s we were able to spray fungicide down in the canopy in drilled soybeans (7” rows), so I see no reason why we need to plant wide rows. There are only 2 cultural practices that I would suggest for 2005: 1) use tram lines or skip rows so you can operate spray equipment without running over beans and 2) drop seeding rates. We know that we overplant in Ohio and seed costs continue to rise, so maybe this is the year to shoot for 180,000 to 200,000 seeds per acre instead of planting 250,000 or more. The seed quality is higher than last year and the seed is much bigger so this will be a good year to try this.

Combining Fungicides with herbicides –Purdue printed an article on combining soybean rust fungicides with herbicides and I guess we need to clarify a few things. Ohio State is not recommending this practice at this time, unless the spray application timing is correct for rust control and weed control. There were reports from South Africa and some areas in Brazil that had very high levels of soybean rust in the vegetative phase, or before flowering. In those cases, fungicides were applied at this early growth stage to knock back the inoculum level in the fields. We have no idea if this was effective or had any impact on the rate of development of soybean rust. So Mark Loux and I put our heads together – actually he’s the brains in this one, and examined some of the potential Section 18 fungicides in combinations with several glyphosate products. Results were: first, we did not see any phytotoxic effects among the treatments, and secondly, there was no impact on the efficacy of the herbicide. The only disease present was Septoria brown spot both years of the trial. The first year we saw some differences among treatments for control of brown spot; none in the second year – but more importantly controlling brown spot had no impact on yield. The primary time to protect soybean plants from soybean rust with fungicides will be during the flowering and pod development growth stages. These are the times when soybean rust will have the largest impact. Vegetative (pre-flowering) timing of fungicide applications will not be recommended unless we can show that reducing inoculum levels can improve fungicide efficacy at later application periods. We have a lot to learn over the next few years if we need to deal with soybean rust on annual basis and we will continue to collect the pertinent data. We will not disregard any attempt to save growers money in management costs. Economics will continue to play a critical role in managing soybean rust. As Brazil continues to expand production and US costs continue to increase, we will have to be innovative and strategic every time we drive across that field.

More Section 18 and Section 3 Approvals from EPA.
Headline, whose active ingredient is pyraclostrobin, and is a strobilurin type of fungicide has received a full label. This fungicide will be used as a protectant and is made by BASF.

Stratego, whose active ingredients are propiconazole and trifloxystrobin, a combination product of both a triazole (curative) and strobilurin (protectant), was granted Section 18 or Emergency use label and is produced by Bayer. Individual state approvals will be coming and yes, Ohio has applied for the Section 18 for Stratego.

Laredo, active ingredient myclobutanil, another triazole and one that will be used as a curative, has been approved in Ohio. Ohio’s approval was a bit delayed due to some paperwork snafus—thanks to Bill Pound at ODA for getting this straightened out.

Where Is All the Potassium Going?

Authors: Robert Mullen, Edwin Lentz

This fall some of us have noticed that potassium (K) fertilizer availability is a little low. So where is all the material going? A great majority of K is going to China and Brazil as those countries establish their agricultural industry. Brazil specifically has a large opportunity for agricultural expansion as they have a large area known as the cerrado (over 750 million acres) which is suitable for intensive farming. The soils which dominate the cerrado are typically acidic in nature containing a lot of aluminum, low in organic matter, and generally low in fertility. Just like the crops we grow here in the US, their crops require significant amounts of fertilizer input. In fact they require quite a bit more due to the poor fertility of their soils. Over the past 8 years potash imports into China and Brazil have more than doubled. Each country now imports more than 6.5 million tons of potash. In all likelihood this trend will continue, specifically in Brazil.

So what does this mean for us in Ohio? I do not expect availability of K will continue to be low. The price however may be a different story. While I hope that prices will fall, the global competition for K will continue to increase which will have an impact on the price we pay here in Ohio.

Starter Phosphorus and Potassium

Authors: Robert Mullen

With potassium (K) availability low in some areas and prices high all across the state, producers may be inclined to apply more fertilizer material this winter into early spring. Phosphorus (P) prices are also a little higher due to the high price of nitrogen (specifically those containing ammonium). Depending upon soil test levels, starter materials may be an alternative to fall application. Additional fertilizer will not be necessary for next year if soil test levels are well above the established critical levels for corn and soybeans (see the Tri-State Recommendations at

If soil test levels are below or near the critical level, application of additional fertilizer material is probably warranted. Application of starter P and K may be a good alternative if spring broadcast applications will not fit into your operation and you have starter capability with your planter. Research conducted in the state by Dr. Jay Johnson has revealed that application of starter does not increase yields if soil test levels are above the established critical values (keep this in mind if your fertility practices maintain high levels – you can get away with not applying anything without taking a yield hit).

If you are going to apply starter next year, remember not to apply more than 100 lb/ac of N and K (combined) in the band (2x2 placement) or emergence problems can occur. While you cannot overcome serious deficiencies with starter applications (specifically for K), soil test levels below the critical value may benefit from application of starter fertilizer. Make P and K input decisions on a field-by-field basis. Monitoring the fertility levels of your fields can really pay off; especially with the price we are paying for fertilizers.

More on Northern Corn Leaf Blight: Selecting Hybrids for Resistance to NCLB in 2005

Authors: Peter Thomison, Patrick Lipps, Allen Geyer

Since northern corn leaf blight (NCLB) was particularly severe in many fields planted to susceptible hybrids in 2003 and 2004, we reviewed seed company literature and web sites for information on hybrid resistance available to this disease. Of the 206 hybrids entered in the 2004 Ohio Corn Performance Test (OCPT), no NCLB ratings were available for 132 hybrids; for those that had company ratings, 47 had ratings indicating a high level of resistance whereas 27 had ratings indicating a low level of resistance. The absence of a rating doesn't necessarily imply that the hybrid is susceptible to NCLB, but this lack of information may be a problem for growers in Ohio trying to identify and select hybrids with resistance. Unfortunately, the various rating scales used by seed companies do not provide an understanding of the type of resistance present in their hybrids. In most cases there is no information on whether the hybrid’s NCLB rating is based on specific race resistance (based on the presence of a Ht gene) or the level of partial resistance (sometimes called tolerance). In general, hybrids with Ht gene resistance show a resistant chlorotic lesion response when infected by certain races of the fungus and hybrids with partial resistance have markedly slower rate of disease development than hybrids with little or no partial resistance.

Some of the scales used by seed companies do not provide a "clear cut" resistance rating for NCLB. Will a hybrid with an intermediate rating of 5 or 6 (even 7) on a 1 to 9 scale (with 1=low resistance) provide adequate protection against NCLB problems of the kind we encountered in 2005?

The most common seed company rating system is a scale of 1 to 9, where 1 indicates a low level of resistance. However, rating scales vary among companies. Some of the different scales used are:

1 to 9, where 1 indicates a high level of resistance
1 to 9, where 1 indicates a low level of resistance
1 to 10, where 1 indicates a low level of resistance
1 to 5, where 1 indicates a high level of resistance
1 to 5, where 1 indicates a low level of resistance
5 to 9, where 5 indicates a low level of resistance
Some companies use a qualitative rating, i.e. "good", "very good”, and "average" rating system.

The good news is that adapted, high yielding hybrids with resistance to NCLB are available. Growers, especially those who observed extensive NCLB in their corn fields during the past year, should consult with their seed company agronomists to make certain that the corn hybrids they plant in 2005 have high levels of resistance. Hybrids with a high level of partial resistance, especially those that also have the Ht1 or Ht2 resistance gene, will provide adequate protection during most years in Ohio.

For more information on managing NCLB consult “Northern Corn Leaf Blight Considerations For Ohio Corn Growers” by Patrick Lipps. C.O.R.N Newsletter 2004-36 (October 19, 2004 - October 26, 2004) available online

Year End Entomology Field Research Reports

Authors: Ron Hammond, Bruce Eisley

1) First Year Western Corn Rootworm Sampling
In the last newsletter we listed a summary of the western corn rootworm sampling in soybean in 2004. The individual county data from the sampling can be found on the WEB at:

2) Evaluation of YieldGard Corn Borer Hybrids in 2004
The 2004 growing season represented the eighth year of replicated trials comparing four YieldGard Corn Borer hybrids to their equivalent isolines (without the YieldGard trait) at the OARDC Western and Northwest Agricultural Research Stations. Corn borer injury on the non-Bt isolines at the Western Station in 2004 remained low at 0.3 cavities when corn was planted in April. Corn borer injury was also low at the Northwest Branch Station in 2004 averaging 0.3 cavities per plant. Because corn borer injury has historically been low at the Western Station when corn was planted on a timely basis, a later second planting (May 24) was made at the Western Station in 2004. Corn borer pressure was also low in the late planting averaging 0.13 cavities per plant.

Average yields from the first planting at the Western Station were 219.7 for the YieldGard Corn Borer hybrids and 218.1 for the non-Bt isolines. Average yields from the second planting at the Western Station were 173.4 for the YieldGard Corn Borer hybrids and 167.5 for the non-Bt isolines. There were no significant differences in yield between any of the hybrids and their isolines in either the first or second plantings at the Western Station. Average yields at the Northwest Station were 204.9 for the YieldGard Corn Borer hybrids and 198.6 for the non-Bt isolines.

In addition to the trials at the Stations, field trials with the same hybrids were conducted at eight on-farm sites with the cooperation of OSU Extension Agents and growers. Participants included OSU Extension programs in Brown, Champaign, Darke, Hancock, Knox, Miami, Morrow and Pickaway Counties. The county trials were not replicated but were planted as paired strip trials.

In the on-farm trials, the non-Bt isolines averaged 6.2 bushels per acre greater than the YieldGard Corn Borer hybrids. The average yield difference from all of the trials conducted 2004 was 1.2 bushels per acre in favor of the YieldGard Corn Borer hybrids.
The complete report for 2004 can be found on the web at:

3) Evaluation of YieldGard Rootworm Hybrids in 2004
OSU entomologists compared two YieldGard Rootworm hybrids to their equivalent isolines (without the YieldGard trait) at the OARDC Western and Northwest Agricultural Research Stations. In addition to the trials at the Stations, field trials with the same hybrids were conducted at five on-farm sites with the cooperation of OSU Extension Agents and growers. Participants included OSU Extension programs in Allen, Clark, Knox, Morrow and Wood Counties. The county trials were not replicated but were planted as paired strip trials.

All plots were established in fields that were in corn in 2003 except for the Allen County site that was in soybean in 2003. Rootworm feeding injury was evaluated at each location in July by randomly digging 10 roots per replicate for each treatment. Roots were washed, examined for corn rootworm larval feeding injury and rated in accordance with the 1-6 “Traditional” scale and the Node Injury Scale (0-3). Plots were machine harvested in October.

YieldGard Rootworm hybrids out yielded their isolines by an average of 25.4 bushels per acre under heavy rootworm pressure (root rating of greater than 4) at the Western Station, by an average of 4.4 bushels under light rootworm pressure (root rating of < 2) at the Northwest Station.

Rootworm larval injury was very light at all of the on-farm sites with the isoline hybrids having a root rating 2.00 or less and the YieldGard Rootworm hybrids out yielded their isolines by an average of 1.8 bushels per acre. A complete report of these trials can be found on the WEB at:

Soybean Aphid Update

Authors: Ron Hammond, Bruce Eisley

Extension personnel and researchers from the Midwest and Canada met in early December to discuss future changes in recommendations for soybean aphid management. Everyone was in agreement that the soybean aphid will probably be a major problem this coming summer, 2005. We still will use the same action threshold, an average between 250-300 aphids per plant on 90% of the plants after sampling at least 30 plants. We are also stressing it should be an increasing aphid population, which will require weekly sampling beginning in early July. As we get closer to the summer, we advise growers to read this C.O.R.N. newsletter for further discussions on how best to manage the aphid. The one thing that growers should begin considering now is the use of skip-rows, or tramlines, to make ground application easier. See Extension FactSheet AGF-131-01 for more on the subject of skip-row soybean production Skip rows is an important consideration not only for soybean aphid, but also for application of post-emergent herbicides and for fungicides for soybean rust if necessary.

2004 Ohio Corn Performance Test: An Overview

Authors: Peter Thomison, Rich Minyo, Allen Geyer, Bert Bishop, David Lohnes

In 2004, 200 corn hybrids representing 34 commercial brands were evaluated in the Ohio Corn Performance Test. Testing was conducted in three regions of Ohio, Southwestern/West Central (SW/WC); Northwestern (NW); and North Central/Northeastern (NC/NE), with three test sites established within each region. Testing was also conducted at two other Ohio sites that have unique production environments (Coshocton and Piketon). Entries in the regional tests were planted in either an early or full season maturity trial. These test sites provided a range of growing conditions and production environments.

The 2004 growing season was characterized by above average rainfall and below average temperatures. At test sites where long-term weather data is available, rainfall totals from April to September 2004, ranged from near normal to 9 inches above normal. Soil conditions at planting were generally excellent and promoted uniform emergence and good stands. Rainfall was well distributed throughout the growing season and soil moisture adequate during nearly all stages of crop growth. Cool temperatures helped minimize moisture stress, but slowed crop development of late planted sites.

Favorable growing conditions resulted in outstanding grain yields at most test sites. Foliar diseases and ear rots were present at several sites, especially northern corn leaf blight and diplodia ear rot. Significant disease injury was limited to particularly susceptible hybrids. Stalk lodging was generally negligible except for the Wooster site. At Wooster, lodging ranged from 0 to 46% for hybrids in the early maturity test and 0 to 63% for hybrids in the full season trial. Persistent rains from early May through mid June prevented timely planting of the Bucyrus (Crawford Co.) and Beloit (Mahoning Co.) test sites, both of which are located in the NC/NE region.

Table 1 provides an overview of 2004 hybrid performance in the early maturity and full season hybrid trials by region. Averages for grain yield and other measures of agronomic performance are indicated for each region, in addition, the range in test sites averages is shown in parentheses.

Table 1. A regional overview of the early maturity 2004 Ohio Corn Performance Test.






Grain Yield



Moisture       (%)


Lodging (%)


Emergence  (%)


Final Stand



Test Wt.
















































Table 2. A regional overview of the full season 2004 Ohio Corn Performance Test






Grain Yield



Moisture       (%)


Lodging (%)


Emergence  (%)


Final Stand



Test Wt.
















































Results of the Ohio Corn Performance Trials for 2004 are available online at:

Archive Issue Contributors: 

State Specialists: Peter Thomison, Rich Minyo and Allen Geyer (Corn Production), Bert Bishop and David Lohnes (Computing & Statistical Services), Pat Lipps and Anne Dorrance (Plant Pathology), Robert Mullen (Soil Fertility), Ron Hammond and Bruce Eisley (Entomology) and Ed lentz (Agronomy). Extension Agents and Associates: Greg Labarge (Fulton) 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.