No. 1 Article 7/March 24, 2006

Product Updates in Weed Management for 2006

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.

Impact 2.8SC (topramezone) will be commercially available in 2006. Impact provides postemergence control of certain annual grass and broadleaf weed species in corn. Topramezone controls susceptible weeds by inhibiting the formation of specific plant pigments, similar to the mode of action of Callisto. Impact will often be used in tank mixes with other herbicides (especially atrazine) to broaden the weed control spectrum. It has shown good efficacy on broadleaf species such as velvetleaf, smartweed, pigweed, common ragweed, lambsquarters, and cocklebur, as well as certain annual grasses such as giant foxtail. Application rates range from 0.5 (north of Interstate 80) to 0.75 fluid ounce per acre, and spray additives (such as COC or MSO in combination with an ammonium nitrogen fertilizer) will be required.

Radius 4SC (flufenacet + isoxaflutole) contains the same active ingredients as Epic but is formulated as a liquid and at a different ratio. Radius can be applied at 7 to 28 fluid ounces per acre, and from up to 21 days before planting until corn emergence.

Epic 58WDG

flufenacet = 0.48 lb

12 ounces

flufenacet = 0.36 lb

Define 60DF = 9.6 ounces

isoxaflutole = 0.10 lb

isoxaflutole = 0.075 lb

Balance 75WDG = 1.6 ounces


Radius 4SC

flufenacet = 3.57 lb

20 fl oz

flufenacet = 0.558 lb

Define 4SC = 17.9 fl oz

isoxaflutole = 0.43 lb

isoxaflutole = 0.067 lb

Balance Pro 4SC = 2.15 fl oz

Canopy 75DG (chlorimuron + metribuzin) has been brought back on the market by DuPont. Application rates generally range from 4 to 7 ounces per acre, and may vary depending on tank-mix partner.

Gramoxone Inteon 2S (paraquat) is the next iteration of paraquat-containing herbicides. The labels of Gramoxone Inteon and Gramoxone Max 3S are virtually identical (except for differences in application rates due to differences in amount of active ingredient per gallon). Gramoxone Inteon is designed to improve human safety in cases of ingestion by minimizing paraquat absorption in the digestive system. Over the next 2 years, Gramoxone Inteon will become the primary formulation as Gramoxone Max is removed from the market.

Select MAX 0.97EC (clethodim) is a new formulation of Select used at 6 to 32 fluid ounces per acre. The product can be applied to soybean up to 60 days prior to harvest. Always include a COC or MSO when applying Select MAX alone.

Harmony GT XP 75DF (thifensulfuron) can be applied at 0.083 ounce per acre (1/12th oz) postemergence in corn. Applications can be made to corn up to 12 inches tall or through V5, whichever is more restrictive. This product's weed control spectrum is limited, and Harmony GT XP should not be applied to corn previously treated with Counter insecticide.

Synchrony STS 42DG is now Synchrony XP 28.4DG. Postemergence application rates now range from 0.375 to 0.75 ounce per acre. The 0.375 ounce rate can be applied to non-STS soybean varieties.

Resolve 25DF (rimsulfuron) has been available only in premixes (Basis, Basis Gold, Steadfast, Steadfast ATZ) prior to the registration of Resolve.

Stout 72.5mp (nicosulfuron + thifensulfuron) contains the active ingredients of Accent and Harmony GT XP. The product comes as a "multiple pack" and should be applied to corn at the rate of 0.5 to 0.75 ounce per acre.--Aaron Hager and Dawn Nordby

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