Issue No. 1, Article 9/March 16, 2005
Product Updates in Weed Management for 2005
We'll begin the new season of newsletter articles with an overview of changes in herbicide options available to Illinois producers. The number of new herbicide active ingredients is limited, and many of the items listed in this article describe new premixes of existing active ingredients or changes in formulations. This article is not intended to provide a complete summary of all label changes that have occurred, and we encourage all who use herbicides to consult respective product labels for additional information. We also provide a list of herbicides that were discontinued from our 2005 weed control guide.
Durango and Glyphomax XRT (glyphosate) are identical formulations of glyphosate. These products contain 4 lb. glyphosate acid equivalent per gallon and are formulated as the isopropylamine salt. When applied alone, additional spray additives are not required, but AMS or drift-reducing agents can be included.
Expert 4.88SC (S-metolachlor + atrazine + glyphosate) is labeled for soil applications (up to 30 days prior to planting) in corn and forage or grain sorghum, and postemergence applications in glyphosate-resistant corn hybrids up to 12 inches in height. Application rates range from 2.5 to 3.75 quarts per acre. Sorghum seed must be treated with a safener (Concep III). (Syngenta)
Lexar 3.7L (S-metolachlor + mesotrione + atrazine) contains the same active ingredients as Lumax but is formulated at a different ratio (i.e., less S-metolachlor, about the same mesotrione, and more atrazine; see the comparison following). Similar to Lumax, Lexar may be applied up to 14 days prior to corn planting; however, postemergence applications of Lexar can be made to corn up to 12 inches in height, whereas Lumax restricts postemergence applications to corn 5 inches or less in height. (Syngenta)
Lexar 3.5 qt
1.6 pt. Dual II Magnum
6.27 oz. Callisto
3 pt. AAtrex
Lumax 3 qt.
2.1 pt. Dual II Magnum
6.40 oz. Callisto
1.5 pt. AAtrex
Paramount 75DF (quinclorac) is registered for preemergence and postemergence use in grain sorghum (sorghum up to 12 inches in height). In susceptible species, quinclorac causes symptoms that are similar to those caused by auxin-type (i.e., growth-regulator) herbicides. The product has a somewhat limited weed control spectrum but is particularly effective on certain annual grasses (such as crabgrass) and some annual (such as morningglory) and perennial (such as field bindweed) broadleaf species. Application rates range from 5.3 to 8.0 ounces per acre. Postemergence applications require the addition of a methylated seed oil or crop oil concentrate. (BASF)
Starane 1.5EC (fluroxypyr) is registered for postemergence applications in corn and grain sorghum. Fluroxypry is considered a growth-regulator herbicide, so injury symptoms are similar to those of other active ingredients within this family. Starane may be applied broadcast at 2/3 pint per acre through the V5 stage of corn, prior to sorghum emergence, or postemergence from the 3rd-leaf stage through the 7th-leaf stage of sorghum. Postdirected applications are allowed in sorghum from the 8th-leaf stage to boot. The product has a limited weed control spectrum but is good on kochia and is exceptionally effective against hemp dogbane. (Dow AgroSciences)
Sequence 5.25L (S-metolachlor + glyphosate) is labeled for soil applications in sorghum (grain or forage) and soil or foliar applications in soybean. When using this product in sorghum, seed must have been treated with a safener (Concep). Preplant or preemergence applications can be made in soybean regardless of variety, but apply postemergence only to glyphosate-resistant soybean varieties. Applications of 2.5 to 4 pints per acre may be made up to 30 days before soybean planting to before soybean emergence. Postemergence applications can be made from emergence through the third trifoliolate at up to 3.5 pints per acre. (Syngenta)
Canopy EX (chlorimuron + tribenuron) received a label for use in late 2004. This premix product contains the active ingredients of Classic and Express, and can be used for burndown and residual weed control in soybean. Application timings range from fall or up to 45 days prior to planting. Use rates range from 1.1 to 3.3 ounces per acre; a 1.1-ounce application rate has no rotational crop restrictions based on soil pH and will be suggested as an "equivalent" replacement rate for 2.5 ounces of Canopy XL. Eventually, Canopy EX will replace Canopy XL. (DuPont)
Boundary 6.5EC (S-metolachlor + metribuzin) changed from a 7.8EC formulation for improved storage characteristics. (Syngenta)
Boundary 6.5EC 2.4 pt.
1.65 pt. Dual Magnum
8 oz. Sencor
Boundary 7.8EC 2 pt.
1.65 pt. Dual Magnum
8 oz. Sencor
IntRRO 4EC (alachlor) was Lasso, currently registered for use in soybean and sorghum (seed treated with safener) but not labeled for use in corn. (Monsanto)
Define SC (flufenacet) is a new liquid formulation that replaces the 60DF dry formulation; corn rates range from 15 to 25 fluid ounces per acre, while soybean rates range from 8 to 14 fluid ounces per acre. It can be applied post-emergence through the 5th-leaf collar of corn. (Bayer)
Valor SX (flumioxazin) is a minor change in formulation from Valor. (Valent)
Products Discontinued from 2005 Guide
Lasso 4EC (alachlor)
Canopy 75DG (chlorimuron +metribuzin)
Command Xtra (co-pack of clomazone and sulfentrazone)
Conclude Xact (co-pack of bentazon + acifluorfen and sethoxydim)
DoublePlay 7EC (acetochlor + EPTC)
Tough 5EC (pyridate)
--Aaron Hager and Dawn Nordby