C.O.R.N. Newsletter 2011-11

Dates Covered: 
May 3, 2011 - May 10, 2011
Editor: 
Glen Arnold

Given this outlook, is there a need to switch from full season to shorter season hybrids? Probably not - in most situations full season hybrids will perform satisfactorily (i.e. will achieve physiological maturity or "black layer" before a killing frost) even when planted as late as May 20-25, if not later in some regions of the state.

Results of studies evaluating hybrid response to delayed planting dates indicate that hybrids of varying maturity can "adjust" their growth and development in response to a shortened growing season. A hybrid planted in late May will mature at a faster thermal rate (i.e. require fewer heat units) than the same hybrid planted in late April or early May).

In Ohio and Indiana, we've observed decreases in required heat units from planting to kernel black layer which average about 6.8 growing degree days (GDDs) per day of delayed planting. Therefore a hybrid rated at 2800 GDDs with normal planting dates (i.e. late April or early May) may require slightly less than 2600 GDDs when planted in late May or early June, i.e. a 30 day delay in planting may result in a hybrid maturing in 204 fewer GDDs (30 days multiplied by 6.8 GDDs per day).

There are other factors concerning hybrid maturity, however, that need to be considered. Although a full season hybrid may still have a yield advantage over shorter season hybrids planted in late May, it could have significantly higher grain moisture at maturity than earlier maturing hybrids if it dries down slowly. Moreover, there are many short-to mid-season hybrids with excellent yield potential. Therefore, if you think you may end up planting in late May, consider the dry down characteristics of your various hybrids. During the past two years we’ve seen a wide range of drying conditions. In 2010, some mid- to- full season hybrids had grain moisture levels at harvest similar to those of short season hybrids because of rapid dry down rates. However in 2009, cool, wet conditions after maturity slowed dry down and major differences in grain moisture at harvest were evident between early and full season hybrids.

Late planting dates (roughly after May 25) increase the possibility of damage from European corn borer (ECB) and warrant selection of ECB Bt hybrids (if suitable maturities are available). In past OSU studies, Bt hybrids planted after the first week of June consistently outyielded non-Bt counterparts even at low to moderate levels of ECB. Since many corn growers will be planting stacked hybrids this year, which include Bt resistance for ECB, this may be a non-issue unless there’s a need to switch to earlier maturing hybrids.

For more information on selecting corn hybrids for delayed planting, consult "Delayed Planting & Hybrid Maturity Decisions", a Purdue/Ohio State University Extension publication available online at: http://www.agry.purdue.edu/ext/pubs/AY-312-W.pdf .

Nielsen, R.L. and P.R. Thomison. 2003. Delayed Planting & Hybrid Maturity Decisions. Purdue Univ. Cooperative Extension Publication AY-312-W. [On-line]. Available at http://www.agry.purdue.edu/ext/pubs/AY-312-W.pdf [URL accessed Apr 2011].

( http://ohioline.osu.edu/b472/0002.html ) provides GDDs for various sites in May through the 10% probability date of the first frost (first occurrence of 32 degrees F) in the fall.  However, GDD accumulations based on a 10% probability of frost may be to “conservative” for use in selecting hybrids for delayed plantings, so we have provided a listing of GDDs available based on the 50% chance of frost occurrence in the fall (Table 1). Moreover this listing includes GDD accumulations through the 50% frost date for two June planting dates. The GDD accumulations  shown in Table 1 were determined by H.M. Keener and R.C. Hansen and reported in OARDC Research Circular 294 “Expected Yield for Corn in Ohio as a Function of Location and Planting Date”. The GDD values shown for the 89 Ohio locations are based on long term weather data (10-72 years).

 Although there is a significant reduction in GDDs available for late planted corn compared to early planted corn, remember that GDD requirements for corn decrease by about 6.8 days for each day that planting was delayed. See this week’s C.O.R.N. article - “Will Planting Delays Require Earlier Maturing Corn Hybrids?” for more information on this topic.

 

Table 1.  Average growing degree day (GDD) accumulations for 6 planting dates from April 30 to June 19 for 89 Ohio locations (source: Keener and Hanson, 1992).

 

 

Accumulated GDD Means

 

April

 

May

 

June

Location

30

 

10

20

30

 

9

19

Akron-Canton

2779

 

2672

2540

2395

 

2198

1991

Ashland

2816

 

2705

2568

2409

 

2209

1996

Barnesville

2644

 

2529

2384

2222

 

2020

1814

Bellefontaine

2946

 

2829

2682

2511

 

2301

2078

Bowling Green

3010

 

2891

2746

2571

 

2358

2129

Bucyrus

2739

 

2625

2490

2326

 

2121

1908

Cadiz

2972

 

2847

2697

2522

 

2319

2097

Caldwell

3007

 

2875

2716

2539

 

2323

2100

Cambridge

2940

 

2807

2645

2463

 

2246

2020

Canfield

2587

 

2489

2365

2200

 

2016

1813

Carpenter

2965

 

2826

2654

2470

 

2246

2018

Castalia

2793

 

2687

2561

2413

 

2213

2015

Celina

3056

 

2927

2771

2601

 

2377

2159

Centerburg

2682

 

2560

2413

2256

 

2057

1858

Chardon

2644

 

2549

2429

2297

 

2114

1919

Charles Mill Dam

2497

 

2396

2267

2118

 

1930

1731

Chillicothe

3209

 

3069

2897

2706

 

2476

2238

Chilo Meldahl Dam

3293

 

3159

2985

2800

 

2572

2337

Chippewa-on-the-Lake

2687

 

2575

2439

2280

 

2085

1877

Cincinnati-Abbe

3435

 

3300

3136

2932

 

2706

2454

Circleville

3179

 

3041

2868

2680

 

2449

2210

Columbus-OSU

3081

 

2955

2802

2625

 

2413

2181

Columbus City

3290

 

3162

3005

2820

 

2600

2358

Coshocton

2960

 

2830

2671

2490

 

2273

2049

Dayton

3442

 

3302

3133

2936

 

2695

2441

Defiance

2827

 

2716

2582

2416

 

2213

1996

Delaware

2891

 

2771

2623

2451

 

2240

2019

Dennison

2776

 

2648

2497

2322

 

2116

1898

Dorset

2389

 

2290

2170

2035

 

1865

1700

Eaton

3006

 

2879

2727

2561

 

2335

2121

Elyria

2896

 

2783

2647

2491

 

2289

2072

Fernbank Dam

3364

 

3226

3061

2879

 

2644

2406

Findlay

2806

 

2695

2560

2397

 

2194

1977

Franklin

3126

 

2990

2826

2649

 

2413

2180

Fredericktown

2689

 

2573

2434

2280

 

2078

1870

Fremont

2890

 

2776

2639

2481

 

2267

2050

Gallipolis

3242

 

3089

2907

2707

 

2474

2233

Geneva

2724

 

2634

2520

2389

 

2207

2010

Greenville

2695

 

2578

2431

2275

 

2063

1861

Hamilton

3296

 

3154

2979

2785

 

2550

2309

Hillsboro

3090

 

2961

2804

2625

 

2414

2185

Hiram

2668

 

2565

2440

2289

 

2110

1911

Hoytville

2809

 

2684

2532

2361

 

2145

1930

Ironton

3459

 

3299

3115

2909

 

2675

2425

Irwin

2825

 

2704

2552

2383

 

2173

1952

Jackson

2916

 

2775

2607

2421

 

2202

1978

Kenton

2832

 

2716

2576

2412

 

2216

1999

Lancaster

2956

 

2826

2666

2489

 

2271

2044

Lima

2941

 

2822

2675

2501

 

2289

2064

London

2934

 

2813

2662

2491

 

2280

2056

Marion

2941

 

2818

2668

2493

 

2279

2053

Marysville

2823

 

2705

2560

2395

 

2190

1974

McConnelsville

3029

 

2897

2740

2561

 

2353

2126

Millersburg

2790

 

2673

2528

2363

 

2160

1948

Millersport

2488

 

2376

2242

2085

 

1893

1693

Mineral Ridge

2803

 

2686

2538

2374

 

2171

1957

Montpelier

2906

 

2789

2647

2476

 

2271

2052

Napoleon

2896

 

2779

2638

2470

 

2271

2049

Newark

2894

 

2767

2611

2434

 

2221

1999

New Lexington

2815

 

2685

2523

2350

 

2139

1924

Norwalk

2792

 

2681

2543

2381

 

2187

1977

Oberlin

2808

 

2693

2555

2392

 

2194

1982

Painesville

2821

 

2737

2622

2488

 

2301

2101   

Pandora

2746

 

2631

2490

2328

 

2118

1898

Paulding

2852

 

2736

2595

2426

 

2222

2004

Peebles

3113

 

2972

2800

2612

 

2386

2152

Philo

3046

 

2907

2740

2557

 

2336

2109

Plymouth

2786

 

2669

2528

2365

 

2166

1951

Portsmouth

3546

 

3393

3207

3003

 

2759

2508

Put-in-Bay

3142

 

3050

2934

2776

 

2573

2343

Ravenna Arsenal

2562

 

2451

2317

2168

 

1978

1775

Sandusky

3094

 

2991

2865

2701

 

2495

2269

Senecaville Dam

2788

 

2665

2511

2342

 

2130

1913

Sidney

2846

 

2730

2588

2432

 

2219

2005

Springfield

3116

 

2979

2813

2635

 

2416

2186

Steubenville

3033

 

2910

2756

2588

 

2376

2156

Tiffin

2953

 

2834

2690

2518

 

2308

2085

Tom Jenkins Dam

2519

 

2392

2243

2084

 

1886

1688

Upper Sandusky

2935

 

2815

2666

2493

 

2279

2054

Urbana

2889

 

2773

2627

2458

 

2250

2031

Van Wert

2973

 

2848

2697

2520

 

2308

2082

Warren

2743

 

2625

2483

2320

 

2119

1910

Washington Court House

3081

 

2954

2794

2617

 

2398

2170

Wauseon

2752

 

2645

2513

2351

 

2152

1937

Waverly

3043

 

2903

2733

2547

 

2323

2092

Wilmington

3088

 

2954

2789

2606

 

2383

2154

Wooster

2649

 

2542

2410

2255

 

2067

1859

Xenia

3044

 

2912

2748

2566

 

2345

2117

Zanesville

2740

 

2618

2468

2308

 

2099

1883

However, Ohio research has shown that yields drop as much as 10 -15% when single N applications have been delayed to Feekes Growth Stage 9 (boot). In a split program there may not be any yield reduction with the delayed application.  If application is delayed to Feekes GS 9, a single application program may want to reduce the N rate to reflect the reduction in yield potential.

A split program probably should stay with its original rate. Nitrogen source will be dependent on price, availability, and application options. Ohio research did not observe any yield differences among urea, urea-ammonium nitrate (28% solution) or ammonium sulfate when applied at later growth stages. To minimize leaf damage, nozzle selection and the use of streamer bars would be recommended with UAN -- damage to the flag leaf may significantly reduce yield.

Also consider, if the weather forecast is for an extended drying period with windy and warm temperatures (>75°) and no rain for several days, you may want to consider a urease inhibitor with urea applications. Slow release and controlled-release N products should probably be avoided since the wheat crop needs the N now and until flowering and not so much later. Since the growing crop will use N now, nitrification inhibitor-type products would be of little benefit and most likely not worth the extra cost.

In summary, for those who have wheat beyond stem elongation (Feekes 7) and N has not yet been applied, you should still get out and apply N.  You might have lost some yield potential if the crop has been N stressed, but the crop will still respond.

The quick answer I am suggesting for this year is May 15. I have planted that late before in central Ohio, although it is not ideal and involves higher risk of failure. If you can't get planted by May 15, consider waiting until August to seed the perennial forage stand.

Soil temperatures on April 29th ranged from 45 to 57 F, so they are still quite cool, and certainly wet. Most plants are lagging behind normal developmental stages for this time of year. That's why I think we can plant a little later this year; however, we know how quickly the weather can change to turn warm and dry.

The later we plant, the greater is the risk of hot, dry, windy weather that can kill new seedlings before they have a chance to establish strong root systems. Weed pressure will be greater with later planting, because seedlings will not get an early jump on annual weeds. It is essential to be prepared to control weeds in late plantings, and do so on a very timely basis! A burndown spray using glyphosate or paraquat before planting may be needed if weeds are already present, especially for no-till or reduced tillage seedings.

There are many good options for weed control in pure alfalfa seedings (see 2011 Weed Control Guide, https://agcrops.osu.edu/specialists/weeds/specialist-links/2010%20Weed%20Control%20Guide.pdf). Eptam and Balan can be pre-plant incorporated, but that requires extra time and effort during the busy planting time. So you may want to rely on post-emergence treatments. Most post products cannot be applied until the alfalfa has at least two to four trifoliolate leaves. During that wait, the weeds emerging with the alfalfa often outgrow it. So be ready to apply herbicides as soon as possible. This will be a good year for the Roundup Ready alfalfa option, because glyphosate is more effective on larger weeds and is very safe to young alfalfa seedlings.

There are fewer herbicide options for legumes other than alfalfa. Eptam and Balan can be applied pre-plant and Butyrac 200 can be post-applied on clovers and birdsfoot trefoil. There are no herbicide options for selective weed control in grass-legume seedings. Mowing is the only recourse for weed control.

Pure grass seedings used for forage can be treated for broadleaf weed control with dicamba after the grass reaches the 3-leaf stage, or with Rage D-Tech from the 5-leaf to boot stage. Be sure to read the label for appropriate rates and be aware of conditions favoring grass injury. Other options exist for broadleaf weed control once the grasses are “well established”. There are no selective grass weed herbicides for grass seedings. Grassy weeds can become very competitive with late spring plantings. If annual grass weeds overtake the perennial grass seeding, the only option is to mow or graze the stand on a regular basis and keep the weeds from going to seed. Assuming the perennial forages establish, next year they will get the jump on weeds and you should have a clean stand.

When you use herbicides, always read the label carefully for proper application rates and restrictions. Be especially mindful of harvest timing restrictions after applying the herbicides.

Since planting season is being severely constrained this spring, consider how to get the job done more efficiently. One way to plant more quickly is to no-till or use reduced tillage, or seed into a stale seedbed if it was prepared last fall.  Crop residues of corn, soybeans, and small grains are not a problem for most drills, but consider whether there are ridges along the rows that can make the field too rough for comfortable hay making.

Fluid seeding is another practice that can speed up planting. The seed is distributed in a carrier of water or in a fertilizer solution and sprayed onto a tilled seedbed. Custom application is recommended, because special equipment for good seed suspension and distribution is required. Prepare a firm seedbed before “spraying” seed and cultipack after it is applied. Seed should be mixed into solution at the field and applied immediately. Seeding legumes through dry fertilizer air spreaders can be successful as well on well-prepared, tilled seedbeds. The field should be cultipacked before and after broadcasting seed.

If you can't plant by mid-May, it’s probably better to delay planting to August rather than seed just before hot weather sets in. To fill the interim gap, consider planting summer annual grasses such as sudangrass, pearl millet, sorghum-sudan, teff, and foxtail millet. All those species are normally planted in late May to early June when soils are warm.  Foxtail millet won't regrow after an early August hay crop, so it might be the best option if you plan to seed the perennial stand in August.  The other species options will require glyphosate to kill the stand before seeding in August.

Be ready, so you don't miss chances to plant. But above all, be careful and follow safe operating procedures. Haste not only makes waste, it can be very dangerous to your health.

After a 46 month environmental impact assessment process, the ruling by the USDA means that U.S. farmers are free to plant genetically altered alfalfa without restrictions. I found it worthwhile to browse the documents outlining the USDA’s position and assessment of the issues surrounding glyphosate-tolerant (GT) alfalfa, available at http://www.aphis.usda.gov/biotechnology/alfalfa_documents.shtml.

Opponents to this ruling have been vocal in their disapproval. They are concerned that without any restrictions, genetically modified alfalfa might contaminate organic and conventional alfalfa seed production and increase the occurrence of glyphosate-resistant weeds. The USDA concluded these issues were not of sufficient impact to justify placement of restrictions on use of Roundup Ready Alfalfa. Further court battles have already been initiated by groups opposing the USDA’s decision.

Whether you agree or disagree with the decision, the fact remains that Roundup Ready Alfalfa has been approved for planting this spring. Many producers will find it to be useful on their farms, while others will not adopt the technology for practical or philosophical reasons. For those considering its use, what factors should be considered? Where might Roundup Ready Alfalfa be of benefit?

We know that good managers have been able to control weeds in alfalfa to acceptable levels with current herbicide optons and best management practices; however, glyphosate is effective on many types of weeds, so it adds another tool to the toolbox in the battle for high quality alfalfa. Glyphosate may be especially helpful during stand establishment because it causes less injury to seedling alfalfa than most other herbicides used during stand establishment. It also controls a broader range of weeds than other alfalfa herbicide options.

We participated in a 5-year study evaluating Roundup Ready Alfalfa across six states. Glyphosate was compared with an alternative herbicide program and a no herbicide check. At all locations, glyphosate controlled weeds with no crop injury during the establishment year. Controlling weeds with either glyphosate or alternative herbicides resulted in greater alfalfa yield and greater forage quality compared with not using herbicides. Controlling weeds increased crude protein content by 3 percentage units and decreased NDF by 3.8 units on average across all locations in the seeding year.

During the seeding year of our study, alfalfa yield was 0.44 ton/acre higher in the glyphosate treatment than in the alternative herbicide treatment, but total forage (alfalfa + weed) yields and forage quality did not differ between the glyphosate and alternative herbicide treatments.

After the seeding year at most locations, herbicides were NOT needed for weed control, even into the fifth year. The alfalfa stand was vigorous and provided sufficient competition to keep weeds from re-invading for the remainder of the stand life, through the fifth year.

Keep in mind that those studies were conducted with small plot equipment so wheel traffic was not an issue. Under normal farm production practices, alfalfa stands tend to be weakened by wheel traffic and weeds can re-invade sooner than under experimental plot conditions. This is particularly true with the large equipment used on many farms today. The Roundup Ready technology will be especially useful where troublesome perennial weeds take hold later in the life of the stand. Examples include thistles, curly dock, and dandelion, which are hard to control with other herbicides labeled for alfalfa. Winter annual weeds can also be controlled well by glyphosate.

Roundup Ready Alfalfa is being marketed by several companies. Variety tests established in 2006 showed the yield of Roundup Ready Alfalfa varieties compared very well with yield of conventional elite alfalfa varieties.

Roundup Ready seed will be more expensive, so the need for glyphosate in weed control should be weighed against the extra seed cost to use this technology. Consider your goals and the importance of weed-free alfalfa in your particular situation.

Glyphosate tolerant alfalfa should be grown judiciously because of the risk of developing glyphosate-resistant weeds. Resistant weeds are likely to develop more rapidly if glyphosate is used on all crops. Just as crop rotation is important, so is rotation of herbicide chemistries. In addition, some customers won’t buy genetically engineered crops, so you need to know what your customers will accept.

As genetically modified alfalfa use increases, we will learn the degree to which glyphosate tolerant genes occur in conventional and organic alfalfa.  In the USDA’s Record of Decision, this and other concerns are discussed in detail. It is well worth the read. I hope the concerns with contamination by genetically modified alfalfa can be adequately addressed so conventional and organic alfalfa production can continue without undue additional cost and effort by producers choosing those systems.

There are other genetically engineered alfalfa traits in development that are likely to be more useful than glyphosate tolerance. A good example is the development of alfalfa varieties with lower lignin concentrations, that have been shown to increase milk production in lactating dairy cows.

In summary, Roundup Ready alfalfa has been deregulated and will be planted this spring. If you decide to use this technology, I encourage you to read through the USDA’s “Record of Decision”, found at http://www.aphis.usda.gov/brs/aphisdocs/04_11001p_rod.pdf. Be informed and use this technology wisely as part of an overall well-managed system. Respect your neighbor’s desire and right to produce organic crops on his/her farm and work together so both of you can achieve your goals.

Concerning the brown marmorated stink bug, this insect has yet to be observed causing injury to either corn or soybean Ohio, but we expect this to change in the coming years.  They are already causing damage to both crops in the Mid-Atlantic States.  Whether damage occurs in Ohio this year will be one thing we are going to keep our eyes on.  This stink bug needs our monitoring because it has the potential to become a significant pest on both crops.  A fact sheet on the brown marmorated stink bug can be found at http://entomology.osu.edu/ag/images/Marmorated_Stink_Bug.pdf, which addresses this pest on all crops including fruit and vegetables.

We have recently developed tables of the insecticides registered on corn and soybean that are labeled for control of stink bugs and placed them into Bulletin 545 that is available at our Agronomic Crops Insects web site, http://entomology.osu.edu/ag/.

However, the need for controlling any of these stink bugs this year is low, albeit this might change in the future.  We will keep growers informed throughout this summer and into the future as to changes in stink bug populations and the need for management.  We are writing a new fact sheet on stink bugs on field crops that we plan on having out this summer.  Keep reading this C.O.R.N. newsletter this summer for more information on stink bugs.

 

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About the C.O.R.N. Newsletter

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.