http://www.ag.ohio-state.edu/~corn/

CORN
Crop Observation and Recommendation Network

For March 1-12, 1999
C.O.R.N. 99-2

In This Issue:

A) Nitrogen Topdress on Wheat
B) Ask About Disease Resistance for Transgenic and Specialty Hybrids/Varieties
C) Soybean Cost Cutters for 1999 & 2000
D) White Food Grade Corn Performance
E) "Take the Test, Beat the Pest" Soybean Cyst Nematode (SCN) Update

A) Nitrogen Topdress on Wheat - Ed Lentz CORN Questions

Nitrogen application on wheat fields should begin at spring green-up. A realistic yield goal is essential to determining N rates. At this time, the yield potential should be high since many wheat fields have suffered little winter damage. Heaving during March is still a concern. A general recommendation is one pound of nitrogen for every bushel of expected grain. For most growers that would be rates between 80 – 100 pounds of nitrogen. You may want to increase this rate 10-15% if your yield expectations are greater than 90 bushels. These rates are based on mineral soils, which have both 1-5% organic matter and adequate drainage. Nitrogen rates would need to be reduced on soils with high organic matter to decrease the risk of lodging. For more detailed information, please refer to the extension bulletin E-2567, Tri-State Fertilizer Recommendations for Corn, Soybeans, Wheat and Alfalfa.

In most years, nitrogen may be applied between early March and early April. Research by the Ohio State University has shown mixed results in splitting spring applications of nitrogen. In years where nitrogen loss is high early in the season, a split application may be a benefit. If you are following a split program, it is important that the first application occurs soon after initial green-up and the second application is at initial jointing (Feekes Growth Stage 6). The time of application is not as critical in a single topdress, but applications should be made after initial green-up and before initial jointing.

Most forms of nitrogen are satisfactory for wheat. Urea and 28% solution (urea-ammonium nitrate) are often the most common. Urea has the least potential to cause damage to the crop. Damage is generally insignificant from broadcast applications of 28% solution applied early, but the potential for damage greatly increases as we approach initial jointing. Dribble applications will minimize damage from 28% solutions. Urea-ammonium nitrate solutions will have some nitrogen available at application time; urea will have a short lag as it converts to ammonium and nitrate forms of nitrogen. Generally, 28% solutions have the greatest potential for nitrogen losses since part of it is in the nitrate form. Urea may have volatilization losses if temperatures are warm and if soil conditions are dry.

B) Ask About Disease Resistance for Transgenic and Specialty Hybrids/Varieties - Pat Lipps and Anne Dorrance CORN Questions

New corn hybrids and soybean varieties carrying transgenic traits such as herbicide and insect resistance have been in great demand over the past two growing seasons. Interest is also increasing in specialty and identity preserved crops, including high oil corn, food grade corn and soybeans of various types. These specialty and transgenic products are useful tools that provide new production and marketing options. Yet, farmers can not afford hybrids and varieties without sufficient disease resistance. Without sufficient levels of resistance crops are vulnerable to disease related yield losses. Growers should also be aware that certain diseases could affect grain quality to the extent that specialty or identity preserved crops are unfit for their intended purpose.

Be sure to ask about the type of resistance to Phytophthora root rot when ordering new herbicide resistant or specialty soybean varieties. We want to avoid a return to the late 1970' and early 1980's when we lost an average of 300,000 acres of soybeans in the state of Ohio to Phytophthora root rot each year. Make sure the varieties you choose have a high level of Partial Resistance (some seed companies still call this tolerance) and/or Race-Specific Resistance designated as Rps genes. There are numerous races of the Phytophthora fungus including some that can defeat the resistance of all available Rps genes. For example, Rps1-a is no longer effective in Ohio. The Phytophthora resistance genes that appear most effective are Rps1-k, Rps3a and Rps1-c. Varieties with a combination of these genes have provided the best protection in problem fields. Fields in northwest Ohio with a persistent problem from Phytophthora should be planting varieties with appropriate Rps genes and high levels of Partial Resistance. Seed treatment with Apron Fl, Apron XL, or Allegiance at the higher rates will also improve stand establishment.

Corn hybrids should have sufficient levels of resistance to northern corn leaf blight, anthracnose, Gibberella ear rot and stalk rots. Continuous, no-till fields should be planted with hybrids resistant to gray leaf spot as well as the other diseases. There are few hybrids with relatively high levels of resistance to gray leaf spot. We have some evidence that gray leaf spot has a negative effect on oil content of the grain, which may adversely affect high oil hybrids. More research is needed to evaluate the effect of these diseases on corn grain quality.

C) Soybean Cost Cutters for 1999 & 2000 - Jim Beuerlein CORN Questions

Soybean grain prices in 1999 and 2000 are predicted to be in the $4.50 to $5.50 range which doesn't leave much profit even with good yields. Build your production system on the following foundation: If all other inputs are adequate, planting date and row spacing combined account for 50% of yield, drill beans as early as soil conditions allow. If all other inputs are adequate, disease control accounts for 20% of the yield, select disease resistant varieties and treat the seed. If all other inputs are adequate, weed control accounts for 15 % of yield, design a good program for controlling weeds. If all other inputs are adequate, soil fertility and seeding rate account for 7% and 5% respectively, check the soil pH and K levels and calibrate the drill for the desired seeding rate.

Following are actions to consider in reducing cost of production.

Reduce the amount of tillage performed or use none.
Don't apply fertilizer if the soil test levels are above the response level. Soil pH should be above 6.0. Soil P needs to be only 15 PPM or greater for maximum yield. Soil K should be about 165-, 190-, or 215-ppm for a soil CEC of 10, 20, and 30, respectively, for maximum yield. Don't apply nitrogen to soybeans.
Because soybean seed is sold in 50-pound units, buy varieties with small seeds to make a unit plant more acres.
Use public certified varieties to control seed input cost. Public varieties yield well and usually have good resistance to disease.
Buy varieties with proven performance that have been around a couple of years rather than the newer, more expensive ones. Make sure they have yielded in the top 25% of the yield trials where they have appeared. If they have not been compared to other varieties in a University performance trial, don't take a chance on them.
Many of the Roundup Ready (RR) varieties we tested in 1998 had a large yield lag. There were also some very high yielding RR varieties with good disease resistance in the trials. Be very selective if using Roundup Ready varieties.

Note: There are over 500 soybean varieties available each year, but only about half are entered in the Ohio Soybean Performance Trials. Varieties not entered are usually poorer performers than those entered. Selecting a variety that was in that test and had a yield greater than the test average gets you in the top 25% of varieties. If you select one that yielded above average by more than the LSD value, then you are into the best 10% of varieties and those are all similar in performance and yield potential.

Select varieties with as much disease resistance and tolerance as possible as a means of holding onto yield. Such varieties don't cost any more than susceptible ones. Ohio loses 6 to 12 bushels per acre each year due to disease.
Reduce the seeding rate for normal varieties from 200,000 to 170,000 and use seed treatments to produce an adequate stand that is healthy and thus reduces cost. In six years of seed treatment trials, Apron seed treatments have increased yield by an average 2.2 bushels per acre at a cost of less than $3.00 per acre. Seed Treatment Pays.
High seeding rates are used to control weeds, but are not needed for yield. Reducing the seeding rate of RR varieties to 100,000 to 125,000 can reduce the seed cost by half, while having very little effect on yield. A few more ounces of Roundup Ultra may be needed for weed control, but you'll be many dollars ahead. Be sure to treat the seed with fungicide.
For weed control in the normal varieties, use reduced rates of post emergence herbicides where weed pressures are moderate to low. Pay close attention to herbicide application timing.
Don't keep your grain to use for seed. Hundreds of studies show that while saved grain is cheaper than purchased seed, yet yield losses from saved seed are almost always greater than the savings in seed cost, resulting in less profit.
Inoculate your seed with one of the new/improved inoculation materials. Our average yield increase from 23 field trials over four years with several products in each has been 3.0 Bu/Ac generating a profit of $13.00 per acre.
When prices are low, there are numerous worthless products and fast-talking sales people that make those products sound really great. If they don't show you data from several University evaluations, then don't waste your time with them.

D) White Food Grade Corn Performance - Peter Thomison, Allen Geyer, David Jordan and Rich Minyo CORN Questions

White corn is receiving greater attention by Ohio corn growers as an alternative to yellow dent corn. Premiums are available for white corn grown under contract. We conducted a white corn test in Ohio at the OARDC NW Branch at Hoytville in 1998 as part of a multi-state testing program coordinated by Dr. Larry Darrah, USDA-ARS, and the University of Missouri. Results of the 1998 Ohio trial are shown in Table 1. In 1998, 33 white corn hybrids were evaluated along with two yellow corn check hybrids. Test results provide growers with a basis for comparing the relative performance of commercial white corn hybrids and yellow corn hybrids.

Multi-state white corn yield test program results are published yearly. Data presented in the publication include food quality characteristics as well as the typical agronomic traits. For information about the food corn tests and annual field day check the following web site: http://www.agron.missouri.edu/ars_columbia/fcpt&fd.html

Please contact Peter Thomison (phone: 614-292-2373; e-mail: thomison.1@osu.edu) if you would like to receive a copy of "White Food Corn - 1998 Performance Tests, Spec. Rep. 518."

Table 1. Yield and agronomic data from the 1998 Early White Food Grade Corn Performance Test at Hoytville, OH.

                        			Stalk
Brand/Hybrid		Yield	Moist.	Stand	Lodged 
			(Bu/A)	 (%)	 (%)	 (%)
AgriGold A6530W		139.4	24.7	98.5	1.9
AgriGold A6680W		150.0	25.3	95.4	9.4
Asgrow RX776W 		141.0	25.9	93.1	1.3
Asgrow XP7308W		127.4	23.1	95.4	10.4
Asgrow XP8118W		137.9	27.2	85.4	0.9
DeKalb DK665W		140.5	24.6	99.2	0.8
DeKalb EXP868W		148.6	24.0	87.0	5.9
Diener DB114W	 	141.0	26.1	101.5	2.9
Garst 8419W		143.1	24.4	98.1	15.7
Garst 8490W		136.0	23.6	80.1	7.9
Garst 8527W		132.6	22.9	64.0	0.0
IFSI 90-1		156.0	24.1	85.8	9.3
IFSI 95-2		142.1	24.2	101.9	0.4
IFSI 98-2		140.8	27.5	80.1	1.9
LG Seeds LG2558W	130.8	23.9	90.0	0.5
LG Seeds LG2596W	121.8	24.3	91.6	3.7
LG Seeds NB749w		140.9	25.1	97.7	3.6
NC+ 5633W		148.0	24.3	101.1	2.6
NC+ RE372W	 	99.2	23.8	89.3	3.2
Novartis N71-T7		133.8	24.8	99.6	2.6
Pioneer 3463W  		128.6	22.2	97.7	3.1
Pioneer 32H39 		142.5	22.9	97.3	2.9
Pioneer 34P93		126.8	24.6	98.5	20.0
Pioneer X1127DW		146.7	23.7	80.5	1.4
Pioneer X1127FW		151.9	24.9	96.2	10.3
Vineyard V424W		155.3	25.0	95.4	3.6
Vineyard V438W		131.3	25.7	98.1	1.6
Vineyard Vx4337		168.8	26.0	85.4	14.0
Whisnand 50AW		150.2	23.3	101.1	8.6
Whisnand 51AW		145.8	24.0	94.6	4.4
Wilson 1780W		138.3	26.8	103.8	1.8
Wilson 1790W		151.2	26.1	88.9	6.7
Wilson E8051		143.3	27.8	101.5	3.1

Yellow Checks
B73 x Mo17		158.2	25.1	87.7	4.7 
Pioneer 3394		164.9	22.8	99.2	7.5

Mean			141.6	24.7	93.2	5.1
LSD (0.05)		11.7	0.9	9.6	7.5
CV%			5.1	2.3	6.3	89.7

* Stand is expressed as a percentage of the planted stand (plots were planted at 30000 seeds/acre)

E) "Take the Test, Beat the Pest" Soybean Cyst Nematode (SCN) Update - Nancy Taylor and Mac Riedel CORN Questions

A total of 2,663 soybean cyst nematode samples were processed from Jan. 1, 1998 through January 31, 1999. Samples results for the period have been summarized into five categories and are listed below.

1) SCN not detected– 1612 (61%)

2) SCN detected, Trace population (40-199 eggs per 200 cc soil)– 343 (13%)

3) SCN detected, Low population (200-2,000 eggs per 200 cc)- 386 (14%)

4) SCN detected, Moderate population (2,000-5,000 eggs per 200 cc)- 145 (5%)

5) SCN detected, High populations (5,001+ eggs per 200 cc)-177 (7%)

For more information on the Ohio SCN Testing including test results listed by county (posted monthly) and Ohio management information visit the following web site: www.ag.ohio-state.edu/~ipm/scn/scn.htm

Readers can subscribe electronically to this newsletter by sending an e-mail message to: corn-out-on@postoffice.ag.ohio-state.edu. A successful subscription message will receive by an automatic reply from the listserv. Contact your local Ohio State University Extension Office or e-mail labarge.1@osu.edu if you have problems subscribing.

Past versions of C.O.R.N. can be found on the World Wide Web at: http:/www.ag.ohio-state.edu/~corn/archive/

C.O.R.N. is a summary of crop observations, related information, and appropriate recommendations for Ohio Crop Producers and Industry. C.O.R.N. is produced by the Ohio State University Extension Agronomy Team, State Specialists at The Ohio State University and Ohio Agricultural Research and Development Center. C.O.R.N. Questions are directed to State Specialists, Extension Associates, and Agents associated with Ohio State University Extension and the Ohio Agricultural Research and Development Center at The Ohio State University.

Contributors to C.O.R.N. this week include: STATE SPECIALISTS: Pat Lipps (Extension Specialist, Plant Pathology), Jeff Stachler (Extension Associate, Weed Science), Ed Lentz (Northwest District Agronomy Specialist), Jim Beuerlein (Extension Specialist, Soybean and Small Grains), Peter Thomison (Extension Specialist, Corn Production); EXTENSION AGENTS: Larry Lotz (Fayette), Bruce Clevenger (Defiance), Greg LaBarge (Fulton), Dennis Baker (Darke), Ray and Clark Hutson (Seneca).

Editor: Greg LaBarge Web Editor: Nathan Watermeier

Information presented above and where trade names are used, they are supplied with the understanding that no discrimination is intended and no endorsement by Ohio State University Extension is implied. Although every attempt is made to produce information that is complete, timely, and accurate, the pesticide user bears responsibility of consulting the pesticide label and adhering to those directions.

All educational programs conducted by Ohio State University Extension are available to clientele on a nondiscriminatory basis without regard to race, color, creed, religion, sexual orientation, national origin, gender, age, disability or Vietnam-era veteran status.

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Keith L. Smith, Director, Ohio State University Extension.