CORN
Crop Observation and Recommendation Network

February 21 - March 6, 2000
C.O.R.N. 2000-5

In This Issue:

A)    New Herbicides for Corn
B)     New Corn/Soybeans Herbicides
C)    New Herbicides for Soybeans
D)    Glyphosate Products Available on the Farm
E)     Soybean Inoculation Trial Results
F)   Recommendations for Using Inoculants with Seed Treatments and Other Pointers

NOTE: For more information on herbicide selection and effectiveness information consult Bulletin 789, Weed Control Guide for Ohio Field Crops available from your County Extension Office or on the Web at http://ohioline.ag.ohio-state.edu/b789/index.html. Another resource for weed control information is the Ohio Herbicide Selector Program available for download at http://ohioline.ag.ohio-state.edu/lines/acrop.html#SFTWARE

A) New Herbicides for Corn - Mark Loux CORN Questions

"Axiom AT"-(Bayer)-is a premix of Axiom (flufenacet + metribuzin) plus atrazine for preplant/preemergence grass and broadleaf weed control.

"Bicep Magnum TR"-(Novartis)-is a premix of atrazine plus s-metolachlor (Dual II Magnum) plus flumetsulam (Python) for preplant/preemergence grass and broadleaf weed control.  The flumetsulam provides control of triazine-resistant lambsquarters and pigweed, which are not controlled by Bicep II Magnum and other atrazine/acetamide premix products.  The rate of atrazine in Bicep Magnum TR is about two-thirds that in Bicep II Magnum, so control of giant ragweed, cocklebur, and and annual morningglory may be reduced with the former product.  Flumetsulam provides little control of these weeds, so it does not compensate for the reduced rate of atrazine.

"Celebrity Plus"-(BASF)-is a premix of nicosulfuron (Accent) and Distinct (dicamba plus diflufenzopyr) for postemergence control of grass and broadleaf weeds in corn.  This product replaces Celebrity, which was sold in 1999.  Celebrity Plus can be applied broadcast until corn is 24 inches tall or at the 6-collar stage, whichever occurs first.  This product should be applied with surfactant plus nitrogen fertilizer solution.  Do not apply with crop oil concentrate.

"Degree and Degree Xtra"-(Monsanto)-contain encapsulated acetochlor plus safener.  According to Monsanto, the release of herbicide from the capsule is temperature-activated - occurring only above soil temperatures of 50 degrees.  In OSU research, this product seems to have more longevity of grass control compared to other acetochlor products.

"Distinct"-(BASF)-is a premix of dicamba plus diflufenzopyr for postemergence broadleaf control in corn.  Diflufenzopyr acts as a synergist for dicamba, allowing reduced dicamba rates and improved control of some broadleaf weeds.  Distinct has been effective for control of Canada thistle and hedge bindweed in OSU research trials.  Suppression or control of small grasses has also been observed, primarily when grass is actively growing under adequate moisture conditions and the 6 oz/A rate is used. Distinct can be applied broadcast when corn is up to 24 inches tall, although application rate is reduced from 6 to 4 oz/A when corn is more than 10 inches tall.

"Epic"-(Bayer)-is a premix of isoxaflutole (Balance) plus flufenacet (acetamide component of Axiom) for preplant/preemergence grass and broadleaf weed control.  This product is weak on giant ragweed, cocklebur, and annual morningglory, but controls most other broadleaf weeds.  Some users report effective control of burcucumber with products containing Balance.

"NorthStar"-(Novartis)-is a premix of primisulfuron (Beacon) plus dicamba (Banvel) for postemergence broadleaf weed control in corn.  This product controls most broadleaf weeds, and suppresses or controls seedling johnsongrass, shattercane, and occasionally small foxtail.  Northstar can replace mixes of Spirit or Exceed with Banvel in some areas, and essentially eliminates concerns about carryover to soybeans that have been associated with those products under dry or high pH conditions.

B) New Corn/Soybean Herbicides - Mark Loux CORN Questions

"Axiom"-(Bayer)-is a premix of a new acetamide herbicide (flufenacet) with metribuzin for preplant/preemergence use in corn and soybeans.  Flufenacet is more active than most other chloroacetamides, so less active ingredient is needed.  Weed control properties are similar to other acetamides, but the addition of metribuzin improves control of common ragweed, lambsquarters, pigweed, and a few other other broadleaf weeds.  Currently, the rates labeled for soybeans are too low to provide an adequate period of annual grass control in many fields, but Axiom can be used prior to a planned postemergence program.

C) New Herbicides for Soybeans - Mark Loux CORN Questions

"Domain"-(Bayer)-is a premix of flufenacet plus metribuzin for preplant/preemergence use in soybeans.  This product contains more metribuzin and less flufenacet compared to Axiom, and it is not designed to provide full-season weed control.  Domain is targeted for use in a planned preplant + postemergence program, and will provide control for several weeks after planting.

D) Glyphosate Products Available on the Farm - Mark Loux CORN Questions

Glyphosate will become available in a variety of products over the next several years from various companies.  These will include products containing glyphosate alone, glyphosate plus surfactant, and premixes of glyphosate with other herbicides for preplant use in corn and soybeans and postemergence use in Roundup Ready soybeans.

We generally see little advantage to mixing glyphosate with other postemergence herbicides when applying to Roundup Ready soybeans in narrow rows. Several exceptions to this:

1)      in some areas of the midwest, velvetleaf has been difficult to control with glyphosate if large or drought-stressed.  Data from Michigan State research showed that mixing Basagran and Resource with glyphosate would improve velvetleaf control with the least negative effect on control of other weeds.

2)      OSU research has shown that mixing FirstRate with glyphosate can provide residual control of giant ragweed that emerge after postemergence application.

3)      mixing with Pursuit (as in Extreme) could provide residual control of late-emerging grasses, which has occasionally been a problem in OSU research.

Currently available products include:

Monsanto: "Roundup Ultra" and "Ultra Dry" (Transorb surfactant package), "Roundup UltraMax" (5 lb/gal with Transorb surfactant package), "Roundup" Original (the Roundup we used to know), "Roundup Custom" (for bulk sales- needs to be mixed with surfactant)

Zeneca: "Touchdown" (minor change in glyphosate molecule - same spectrum of control)

Dow:  "Glyphomax" and "Glyphomax Plus" (glyphosate with and without Dow’s surfactant package)

American Cyanamid: "Extreme" (Pursuit plus glyphosate for postemergence use in Roundup Ready soybeans), "Backdraft" (Scepter plus glyphosate for preplant burndown plus residual)

E) Soybean Inoculation Trial Results - Jim Beuerlein CORN Questions

The Soybean Inoculation Trial was started in 1995 and 29 field test have been conducted since that time with three to eight materials being evaluated in each test. Through 1998, (4 years & 23 tests) the average yield increase above the untreated check for using an inoculant was 2.35 bushel per acre.

In 1999, eight inoculation treatments were evaluated at six test sites. At four of these sites the soil was very warm at planting and dried to below seeding depth within a few days due to a lack of rainfall. The continued drought resulted in low yields (30-45 bu/ac) and no response to our inoculation treatments. Germination and emergence did not occur until the first week of June, so the inoculum cells likely dried out and died before the seed germinated. The nodules that formed in these fields were probably produced by native bacteria not near the soil surface and subject to drying before seed germination.

The other two test sites received rainfall soon after planting which allowed the applied inoculum to infect the roots and increase yield by 3.6 bu/ac averaged over those two test sites. The average yield increase for 1999 over all six sites and eight materials was 1.1 bu/ac. Therefore, over five years and 28 field trials the average yield increase from using an inoculum is 2.1 bu/ac.

If soybeans are worth $5.00 per bushel, per acre profit from inoculating soybeans would be $8.00-9.00 per acre or a profit of 400% to 500%. Table 1 contains yield data for the products tested in 1999 at the two sites receiving rainfall shortly after planting.

Table 1. 1999 Yield increase over average (bu/a) at two of eight sites receiving rainfall after planting.

Mean Yields at other 1999 test sites: Henry, 39.9; VanWert, 32.7; Delaware, 41.7; and Darke, 41.2.       

F) Recommendations for Using Inoculants with Seed Treatments and Other Pointers - Jim Beuerlein CORN Questions

Dry and liquid formulations of the same product appear to perform similarly. Once the carrier of the inoculum dries on the seed, the bacterial cell starts dying. Seed should be planted into moist soil within a few hours of inoculation so the bacteria cells will stay moist so the bacterial cell survive long enough to infect the root system following germination.

When applying a fungicide or using fungicide treated seed, be sure the fungicide has dried before applying inoculum to the seed. Currently, inoculum may NOT be mixed with fungicides and applied to seed at the same time together. Work is underway to develop products containing both an inoculant and fungicides.

When loading a drill or planter using an auger, inoculation materials (liquid or dry) should be added to the seed as it enters the auger for thorough application. When loading a drill or planter from bags, fill the seed box to a depth of three inches and scatter the appropriate amount of inoculum over the seed and mix it in thoroughly. Continue to add seed in six inch deep layers, treating each until the seed box is filled. With some dry materials it may be desirable to moisten seed slightly to increase the adherence of inoculum.

Individual seeds need no more than a three to five percent coating of dry material. Liquid materials will usually cover most of the seed. Once dry, liquids have little or no effect on the seed meter flow. Dry materials usually reduce the flow rate of seed through fluted seed metering devices (most grain drills) and may also have undesirable effects on vacuum and air metering systems.

Seeding equipment should be calibrated using the treated seed to be planted. Some seeding rate monitors allow a continuous check of seeding rates so adjustments can be made to the seeding rate if and when necessary.

Both fungicide seed treatments and inoculation can produce large returns relative to their cost and in most cases both should be used. When only one can be used, the fungicide will likely be the more profitable.

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. include: State Specialists: Pat Lipps & Anne Dorrance (Plant Pathology), Hal Willson (Entomology), Peter Thomison (Corn Production), Jay Johnson (Fertility), Jim Beuerlein (Soybeans & Small Grain), Mark Loux (Weed Science), Jeff Stachler (Weed Science); District Specialists: Curtis Young (IPM), Ed Lentz (Agronomy) Jim Jasinski (IPM); Extension Agents: Mike Estadt (Pickaway), Andy Kleinschmidt (Van Wert), Roger Bender (Shelby), Dave Jones (Allen), John Barker (Knox), Steve Bartels (Butler), Larry Lotz (Fayette), Ray Wells (Ross), Clark Hutson (Seneca), Barry Ward (Marion), Dennis Baker (Darke), John Hixson (Union), Bruce Clevenger (Defiance), Gary Wilson (Hancock), Greg La Barge

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.

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