New Herbicides for 2000

March 17, 2000
Several new corn and soybean herbicides will be marketed during the 2000 growing season. While there are several new trade names, no new active ingredients are available in 2000; all "new" herbicides contain previously registered active ingredients. This article is intended to be a short summary of new herbicide additions to the market, not an exhaustive description of each product. Be sure to read and follow label directions before using pesticides.

American Cyanamid

Extreme 2.17L (imazethapyr + glyphosate) is a premix containing the active ingredients of Pursuit and Roundup. The product can be used as a burndown treatment prior to soybean planting or as a postemergence treatment in glyphosate-resistant soybean varieties only. Applications should include a nonionic surfactant and nitrogen-based fertilizer (AMS or UAN). The 3-pints-per-acre use rate provides the equivalents of 4 fluid ounces of Pursuit 2AS and 1.5 pints of Roundup. The imazethapyr component provides several weeks of residual weed control following application, and is especially beneficial for residual control of eastern black nightshade.

Backdraft 1.5L (imazaquin + glyphosate) is a premix containing the active ingredients of Scepter and Roundup. The product will be positioned primarily in the southern portion of Illinois, where the potential for imazaquin carryover is reduced. Backdraft can be applied at 1.5 to 2 quarts per acre as a burndown treatment up to 45 days prior to soybean planting or as a postemergence treatment in glyphosate-resistant soybean varieties only. Postemergence applications should include a nonionic surfactant or an organosilicone surfactant (1 pint per 100 gallons).

Bayer

See Table 4 and Table 5 for additional information.

Domain 60DF (flufenacet + metribuzin) is a soil-applied soybean herbicide containing the same active ingredients as Axiom but at a different ratio. Axiom, introduced in 1999 for use in corn and soybean, contains flufenacet + metribuzin at a 4:1 ratio, whereas Domain contains the same active ingredients at a 1:1.5 ratio. Use rates of Domain range from 9 to 16 ounces per acre, which can be applied preplant (up to 14 days prior to planting), preplant incorporated, or preemergence. The addition of a crop oil concentrate to Domain can enhance the burndown activity on certain weed species prior to planting no-till soybeans. Duration of grass and broadleaf weed control depends on use rate (determined by soil texture and organic-matter content). Domain should be used in conjunction with additional tank-mix partners or supplemental postemergence herbicides. Certain soybean varieties can be inherently more susceptible to metribuzin than other varieties. Soybean injury may occur when Domain is applied to soils with a pH of 7.5 or greater.

Axiom AT 75DF (flufenacet + metribuzin + atrazine) is a corn herbicide premix that contains the active ingredients of Axiom plus atrazine. Use rates depend on soil texture and organic-matter content and range from 1.5 to 3.75 pounds per acre. Axiom AT may be applied preplant (up to 45 days prior to planting), preplant incorporated, or preemergence. Do not use Axiom AT or Axiom on corn grown for seed.

BASF

Outlook 6EC (dimethenamid-p) contains the resolved isomer of dimethenamid and is used at about 55% of the Frontier use rate. For example, 28 fluid ounces of Frontier would be equivalent to approximately 16 fluid ounces of Outlook. Limited quantities of Outlook will be available in 2000 (primarily for test markets), and full conversion to the resolved isomer formulation is expected by 2001.

Celebrity Plus 70WDG (nicosulfuron + dicamba + diflufenzopyr) is a premix of the active ingredients contained in Accent and Distinct. Celebrity Plus replaces the Celebrity (nicosulfuron + dicamba) co-pack, which was marketed in 1999. Because of the nicosulfuron component, the Celebrity Plus label contains precautionary statements similar to those on the Accent label about potential herbicide/soil-insecticide interactions. Celebrity Plus may be applied at 4.7 ounces per acre to corn between 4 and 24 inches in height for control of a broad spectrum of annual and perennial grass and broadleaf species. Applications must include a nonionic surfactant and an ammonium nitrogen fertilizer.

Acquire (isopropylamine salt of glyphosate) is sold by BASF in bulk only for use (primarily) in glyphosate- resistant soybean varieties.

Ultra Blazer 2S (acifluorfen) is a new formulation of Blazer.

Dow AgroSciences

Glyphomax and Glyphomax Plus (isopropylamine salts of glyphosate) are essentially equivalent to Monsanto's Roundup and Roundup Ultra, respectively (except for surfactant types and loading), and product labels are similar. Both Glyphomax and Glyphomax Plus are labeled for use on glyphosate-resistant soybean varieties. At present, these herbicides are not labeled for postemergence applications in glyphosate-resistant corn hybrids.

Hornet 68.5WG (flumetsulam + clopyralid) represents a formulation change of the product. Hornet 68.5WG begins to replace Hornet 85.6WG during the 2000 season. The new formulation results in use-rate changes, for example, 3 ounces of the 68.5WG formulation is equivalent to 2.4 ounces of the 85.6WG formulation.

Pendimax 3.3EC (pendimethalin) contains the same active ingredient as Prowl, and the label is similar to the Prowl label.

The herbicide premix Broadstrike + Treflan (flumetsulam + trifluralin) will soon be discontinued. The only remaining inventories are currently located within dealer and distributor inventories, and once these have been depleted the premix will no longer be offered. The identical ratio of products can still be obtained by tankmixing Python with Treflan.

Monsanto

Degree 3.8CS (acetochlor) contains the same active ingredient as Harness but is a new encapsulated formulation of acetochlor designed to extend soil-residual control of annual grass species. Degree will likely be positioned to compete with other soil-applied corn herbicides in the early preplant market. The release of acetochlor from the encapsulation is triggered primarily by soil temperature, with minimal release occurring until soil temperatures reach 50°F. Applications may be made from early preplant (up to 45 days prior to planting) until corn reaches 11 inches in height. Rates range from 2.25 to 5 pints per acre depending on soil texture and organic-matter content.

Degree Xtra 4.04EC (acetochlor + atrazine) is a premix of the encapsulated acetochlor of Degree and atrazine for annual grass and broadleaf control. The atrazine portion of Degree Xtra is not encapsulated. Applications may be made through early preplant (up to 45 days prior to planting) until corn reaches 11 inches in height. Rates range from 2.9 to 4.3 quarts per acre depending on soil texture.

ReadyMaster ATZ 4SC (isopropylamine salt of glyphosate + atrazine) is a premix for postemergence applications to glyphosate-resistant (Roundup Ready) corn hybrids. The formulation contains the equivalents of 2 pounds ai of glyphosate (1.5 pounds acid equivalent) and 2 pounds ai of atrazine. Use rates range from 1.5 to 2 quarts per acre. Make only one application of ReadyMaster ATZ between corn emergence and before corn exceeds 12 inches in height. The addition of ammonium sulfate (8.5 to 17 pounds per 100 gallons of water) may improve performance under adverse growing conditions.

Novartis

Boundary 7.8EC (S-metolachlor + metribuzin) contains the same active ingredients as Turbo but at a slightly different ratio. Boundary is formulated with the resolved isomer of metolachlor (Dual Magnum) but does not contain the safener found in Dual II Magnum. Use rates range from 1 to 3 pints per acre, depending on soil texture, organic matter, and tillage system. Applications may be made up to 30 days prior to planting to after planting but before soybean emergence. The addition of a crop oil concentrate to Boundary can enhance the burndown activity on certain weed species prior to planting no-till soybeans. On soils with a pH above 7, soybean injury caused by metribuzin may occur when application rates are greater than 1.25 pints. To avoid this injury, do not apply Boundary at rates greater than 1.25 pints on soils with a pH above 7. Certain soybean varieties can be inherently more susceptible to metribuzin than other varieties. The Boundary label suggests consulting with your soybean seed supplier for information on varietal tolerance to metribuzin.

Turbo, Broadstrike + Dual, and Broadstrike SF + Dual will be available in limited supply in 2000 and discontinued in all markets when the current inventories have been sold.--Aaron Hager and Christy Sprague

Author: Aaron Hager Christy Sprague