Issue No. 1, Article 11/March 18, 2004
Product Updates in Weed Management
Herbicide changes for 2004 consist primarily of formulation and label changes. No new herbicide active ingredients are expected to be labeled during the 2004 growing season. The following product changes for 2004 are presented by manufacturer.
Prowl H2O is a new water-based formulation of pendimethalin. This new formulation contains 3.8 pounds of active ingredient per gallon (Prowl EC contains 3.3 pounds of active ingredient per gallon) and has less odor than the EC formulation. Stains on clothing, equipment, and so on should be easier to remove. The manufacturer reports that Prowl H2O washes off surface residue easier and has less volatility than the EC formulation. Labeled uses for Prowl H2O and Prowl EC are virtually identical; exceptions include differences in application rates in corn and soybean (due to differences in amount of active ingredient per gallon), no time interval specified to incorporate the H2O formulation when used on soybean (the EC formulation specified to incorporate within 7 days after application), and differences in the feeding/grazing interval when used on corn (21 days after application for the H2O formulation, 12 days for the EC formulation).
Distinct 70WDG (dicamba + diflufenzopyr) is now labeled for postemergence applications on popcorn. Before applying to popcorn, verify the selectivity of Distinct on the popcorn hybrid with your local seed company or supplier.
Equip 32WDG (foramsulfuron + iodo-sulfuron), first commercialized during the 2003 growing season, is used for postemergence control of weed species in all types of field corn. Equip should not be applied to sweet corn, popcorn, or corn grown for seed. Equip is a premix product containing the same active ingredient of Option (foramsulfuron) and iodosulfuron for improved control of certain broadleaf weed species. Broadcast applications can be made when corn is zero to12 inches high or in the emergence through V4 growth stage, whichever is more restrictive. Equip should be applied at 1.5 ounces per acre; only one application per growing season is allowed. Methylated seed oil plus a nitrogen fertilizer is the preferred additive system.
Equip will control several grass and broadleaf weed species. The 1.5-ounce use rate of Equip contains slightly less foramsulfuron than the same rate of Option, so control of certain grass species (woolly cupgrass, yellow foxtail, green foxtail) may be less with Equip than with Option.
Define 4SC (flufenacet) is a new liquid formulation that will eventually replace the 60DF formulation. Application rates of Define 4SC will range from 15 to 25 fluid ounces per acre in corn or 8 to 14 fluid ounces per acre in soybean.
Keystone LA (acetochlor + atrazine) is a premix containing 4 pounds of acetochlor and 1.5 pounds of atrazine per gallon. Keystone LA can be applied to field corn, production seed corn, silage corn, and popcorn up to 30 days before planting, preplant incorporated, preemergence, or post-emergence up to 11-inch-tall corn. Application rates vary according to soil texture and organic matter content, tillage system, and application timing and range from 1.6 to 3 quarts per acre. An application rate of 2 quarts per acre provides 2 pounds of acetochlor and 0.75 pounds of atrazine.
Stinger (clopyralid) was registered for use in sweet corn and popcorn during 2003. Applications of 1/3 to 2/3 pint per acre can be made to popcorn no taller than 24 inches or sweet corn no taller than 18 inches. Do not apply Stinger within 30 days of harvest for ears and forage and 60 days of harvest for stover.
Other label changes from Dow Agro-Sciences include the following: the rotational interval for oats was reduced from 30 months (plus a successful bioassay) to 9 months for FirstRate, and methylated seed oil is an approved additive for postemergence applications of Hornet.
The Assure II (quizalofop) label has been modified to provide use directions for control of glyphosate-resistant volunteer corn. Several supplemental labels have been incorporated into the Section 3 Canopy XL (chlorimuron + sulfentrazone) label, as well as changes in language related to rotational intervals.
IntRRo (alachlor) is very similar to Lasso. One notable difference is that IntRRo is labeled for use in soybean and sorghum (safened seed required) but is not labeled for use in corn.
Roundup Original Max (glyphosate) contains 5.5 pounds per gallon of the potassium salt of glyphosate (4.5 lb a.e./gallon). The formulation contains a "built-in" additive system, but additional surfactant can be added under certain conditions. A use rate of 22 fluid ounces per acre provides the equivalent of 0.75 pound acid equivalent per acre.
Callisto (mesotrione) label changes include reducing the maximum amount allowed per acre per season from 10.7 to 7.7 fluid ounces and modifying the rotational intervals for alfalfa, soybeans, and sorghum to 10 months from 18 months, next year, and next year, respectively.
Gramoxone Max (paraquat) is now labeled for preharvest applications in field corn, popcorn, and sweet corn. Application rates range from 0.8 to 1.3 pints per acre, and all applications should include a nonionic surfactant. Gramoxone Max should be applied after the black layer has formed at the base of the corn kernels and at least 7 days prior to harvest.
Lumax (mesotrione + metolachlor + atrazine) label changes include modifications in rotational intervals for oats (next year), rye (4.5 months), and alfalfa and clover (18 months) from previous intervals of 2 years for each crop.
Camix 3.67L (mesotrione + metolachlor) is labeled for use in Illinois. Camix contains 3.34 pounds of S-metolachlor and 0.33 pound of mesotrione per gallon. Application rates range from 2 to 2.4 quarts per acre, and Camix may be applied from 14 days prior to planting through 5-inch-tall corn.
Expert 4.88L (S-metolachlor + atrazine + glyphosate) can be applied to corn or sorghum (grain or forage, safened seed required) at 2.5 to 3.75 quarts per acre. Expert may be applied from 30 days before planting but before crop emergence. Postemergence applications can be made to glyphosate-resistant corn up to 12 inches in height.
Touchdown Total (glyphosate) contains 4.17 pounds acid equivalent formulated as the potassium salt of glyphosate with the "IQ" built-in additive system. Common application rate is 1.5 pints per acre.
Touchdown HiTech (glyphosate) contains 5 pounds acid equivalent formulated as the potassium salt of glypho-sate without the "IQ" additive system, so applicators can include their own spray additives.
Syngenta will be introducing a new formulation of Boundary (metolachlor + metribuzin) during 2004. Boundary 6.5EC has improved storage characteristics and eventually will replace the 7.8EC formulation.
Gangster V (flumioxazin) and FR (cloransulam) is a new co-pack product combining the active ingredients of Valor 51WDG and FirstRate 84WDG. Use guidelines and restrictions on the Gangster V label are very similar to those listed on the Valor label, while the use guidelines and restrictions on the Gangster FR label are very similar to those on the FirstRate label.
Valor SX is a new formulation of the same active ingredient contained in Valor 51WDG.
Arrow (clethodim), manufactured and marketed by Makhteshim-AGAN of North America (MANA), contains the same active ingredient as Select for postemergence control of grasses.
Stalwart C, manufactured and marketed by Sipcam Agro, contains 7.8 pounds of metolachlor per gallon (similar to Dual), while Stalwart Xtra contains 2.4 pounds of metolachlor and 3.1 pounds of atrazine (similar to Bicep).
Blanket (sulfentrazone) is marketed by Rosen's and is a similar formulation toAuthority 75DF and Spartan 75DF. Labels of Blanket and Authority are similar. However, the Blanket label allows application rates as high as 8 ounces per acre (5.3 ounces is the maximum rate of Authority).
Volley is marketed by Rosen's and contains 6.4 pounds of acetochlor (similar to Surpass), while Volley ATZ contains 3 pounds of acetochlor and 2.25 pounds of atrazine (similar to Surpass 100). Volley ATZ Lite contains 4 pounds of acetochlor and 1.5 pounds of atrazine.--Aaron Hager