2,4-D (several trade names)
Rate 0.5 to 1.0 lb ae/A. Consult label, as 2,4-D labels vary in rates.
Time Apply when corn is actively growing.
Remarks Applying without drop nozzles to corn over 8 inches tall may increase lodging and interfere with normal tassel emergence. Use drop nozzles to avoid applying to corn leaves.
Caution Do not spray corn from tasseling to dough stage. In western Washington, some common annual broadleaf weeds are tolerant to 2,4-D: chickweed, smartweed, black bindweed, knotweed, and redroot pigweed. Note feeding restrictions.
Site of action Group 4: synthetic auxin
Chemical family Phenoxy acetic acid
bentazon (Basagran 5L)
Rate 0.75 to 1 lb ai/A (1.2 to 1.6 pints/A product)
Time For small, annual broadleaf weeds. Apply postemergence to corn when weeds are small and actively growing. Basagran 5L may be tank mixed with one or more of, but not limited to, the following herbicide products: Outlook, Status, Atrazine, and glyphosate.
Remarks Adding oil concentrate generally increases weed control but also may increase corn injury. Use adjuvants as indicated on the label. Irrigate before application to ensure vigorous weed growth. Control is poor if days and nights are below 80°F and 60°F, respectively. Use at least 5 gal/A water and at least 40 psi to ensure thorough coverage of weed foliage. Leaves may speckle temporarily, but plants generally outgrow it within 10 days. Use higher rate with oil concentrate applied twice, 7 to 10 days apart for Canada thistle and yellow nutsedge control.
Caution Do not apply to corn growing under stress, or mix with other pesticides. Do not exceed 2 lb ai/A per season. Seed corn producers should consult the contracting company regarding tolerance of seed production lines. Do not cultivate 5 days before or after application. Do not graze treated corn fields for at least 12 days after the last treatment with Basagran 5L.
Site of action Group 6: photosystem II inhibitor
Chemical family Benzothiadiazole
bromoxynil (Buctril, Brox 2EC and various generic names)
Field corn and popcorn only
Rate 0.25 to 0.5 lb ai/A (1 to 2 pints/A)
Time Apply after corn reaches the three-leaf (0.25 lb ai/A) or four-leaf (0.50 lb ai/A) stage. Effectiveness dependent on weed size.
Remarks Label rates for each product differ; see appropriate label for maximum rate. Use drop nozzles when corn is more than 8 inches tall. Spray when corn foliage is dry to decrease chance of temporary leaf burn. Warm temperatures also increase chance of some foliage burn. Thorough coverage of weed foliage required for adequate control. Buctril is registered for use for application through sprinkler systems; consult labels for use restrictions.
Caution Do not cut for feed or graze within 30 days after treatment. Do not plant rotation crop until the following season. Do not add any spray additive or mix with liquid fertilizers.
Site of action Group 6: photosystem II inhibitor
Chemical family Nitrile
carfentrazone (Aim)
Rate 0.032 lb ai/A (2 fl oz/A Aim EC)
Time Apply to small weeds and when corn is up to the 14-collar growth stage; use directed applications if more than 8-collar growth stage.
Remarks See label for maximum weed size. Add 0.25% v/v nonionic surfactant. If corn grows in very dry soil, a sprayable liquid nitrogen fertilizer may be used in addition to the nonionic surfactant. Any crop may be planted 30 days after application except barley, oats, and rye, which can be planted 12 months after application. Good spray coverage is essential. Adjust sprayer to avoid excess herbicide application over the row and/or into the whorl of the corn plant.
Caution Tank-mixtures of carfentrazone with emulsifiable concentrate (EC) formulations of other herbicides, fungicides, or insecticides, or with crop oil concentrate, methylated seed oil, or silicone-based adjuvants may increase crop injury. Adding nitrogen or ammonium sulfate with nonionic surfactant may increase leaf injury.
Site of action Group 14: protoporphyrinogen oxidase inhibitor
Chemical family Triazinone
clopyralid (Stinger or Spur)
Rate 0.063 to 0.165 lb ae/A (0.25 to 0.66 pints/A)
Time Apply to actively growing broadleaf weeds after corn emerges up to 24 inches tall. For Canada thistle, apply after most basal leaves emerge but before bud stage.
Remarks For best results on Canada thistle, use at least 0.5 pint/A product. Do not cultivate before treatment, and wait two weeks after treatment before cultivation. Re-treat as necessary but do not exceed 0.66 pint/A product per calendar year.
Caution Do not graze treated areas or harvest corn for feed within 40 days of treatment. Wheat, barley, oats, grasses, field corn, or sugar beets may be planted any time after treatment. Do not plant alfalfa, asparagus, canola (rapeseed), Brassica species grown for seed, cole crops, dry beans, soybeans, grain sorghum, mint, onions, popcorn, safflower, sunflower, sweet corn, or strawberries during the first 12 months after applying product. If annual precipitation (not including irrigation) is 18 inches or more-alfalfa, asparagus, dry beans, canola (rapeseed), Brassica species grown for seed, grain sorghum, mint, onions, popcorn, sweet corn, soybeans, strawberries, and sunflowers may be planted 12 months after applying product. Cole crops, lentils, peas, potatoes (including potatoes grown for seed), safflower, or broadleaf crops grown for seed (excluding Brassica species) may also be planted 12 months after treatment; however, unless risk of injury is acceptable, these crops should not be planted until 18 months after treatment. If average annual precipitation (not including irrigation) is less than 18 inches-alfalfa, dry beans, soybeans, sunflowers, lentils, peas, potatoes (including potatoes grown for seed), or broadleaf crops grown for seed (excluding Brassica species) should not be planted until 18 months after applying product. However, crop injury and/or yield loss may occur up to 4 years after application for extremely sensitive species such as tomatoes and legumes.
Site of action Group 4: synthetic auxin
Chemical family Pyridine
dicamba (Clarity, Sterling Blue)
Field, seed and popcorn
Rate 0.25 lb ae/A (1 pint/A)
Time Apply when corn is actively growing and seedling weeds are in the four- to six-true-leaf stage of growth.
Remarks Controls atrazine-resistant pigweed and common lambsquarters. Does not control grass weeds. If grass weeds are present, combine with a grass-killing herbicide or glyphosate if applied over glyphosate tolerant corn. Apply before corn is 24 inches tall, especially if it is growing near sensitive crops. Two applications per year are allowed, but do not exceed 1.5 pints/A.
Caution Verify seed and popcorn tolerance before using dicamba. Do not apply after corn is 3 ft tall, or 15 days before tassels emerge, whichever is first. Some varieties of field corn may show temporary injury after application. Do not graze or harvest for dairy or beef feed before ensilage stage (milk stage). Do not apply when temperature is expected to exceed 85°F. Use spray drift reduction nozzles. To avoid impact to corn development, consider applying at V3-V4 at the latest. Any use of dicamba should have drift and deposition adjuvant added in order to reduce off target movement.
Site of action Group 4: synthetic auxin
Chemical family Benzoic acid
diflufenzopyr + dicamba (Status)
Rate 0.0063 to 0.0125 lb ai/A diflufenzopyr + 0.156 to 0.3125 lb ai/A dicamba (5 to 10 oz/A product)
Time Apply to corn 4 to 36 inches tall (V10).
Remarks Controls broadleaves and suppresses some annual grasses. Add a nonionic surfactant at 1 quart/100 gal spray mix plus 5 quarts of urea ammonium nitrate (UAN) per 100 gal spray mix. Spray-grade ammonium sulfate may be substituted for UAN at 17 lb/100 gal spray mix. Applications can be split; allow at least 15 days between applications. Verify selectivity on the popcorn hybrid with your local seed corn company before using. Crop may be temporarily injured if crop is stressed or rapidly growing. Can be applied with glyphosate to glyphosate tolerant corn, or glufosinate to glufosinate tolerant corn.
Caution Do not exceed 12.5 oz/A product per year. Do not use penetrants such as petroleum-based oils or methylated seed oils; crop may be injured. It is not recommended for use in tank-mixes with plant-growth-regulating herbicides such as 2,4-D, dicamba, or clopyralid unless applications are at least 15 days apart. Preharvest interval is 32 days for silage and 72 days for grain and stover. Do not plant any crop other than corn for 120 days after application.
Site of action (diflufenzopyr) Group 4: synthetic auxin; (dicamba) Group 19: inhibits indole acetic acid transport
Chemical family (diflufenzopyr) Semicarbazone; (dicamba) Benzoic acid
flumiclorac (Resource)
Field corn
Rate 0.027 to 0.054 lb ai/A (4 to 8 fl oz/A)
Time Apply to corn from V2 (2 collars) to V10 stage. Determine the leaf stage of corn by counting only those leaves with visible leaf collars.
Remarks Controls only actively growing, susceptible broadleaf weeds. Rate is determined by weed species and weed growth stage. Flumiclorac must be applied with a crop oil concentrate or methylated seed oil; the amount of additive is determined by the rates and timing. Adding spray-grade ammonium sulfate at 2 to 2.5 lb/A may enhance weed control.
Caution Do not use on sweet corn or popcorn. Verify crop safety before applying to seed corn. Corn leaves open at time of application may show some spotting and burning. Do not apply when corn and weeds are under stress. Do not apply if rain is expected within 1 hour of application. Preharvest interval is 28 days for grazing animals on green foliage or using as feed.
Site of action Group 14: protoporphyrinogen oxidase inhibitor
Chemical family N-phenylphthalimide
fluroxypyr (Starane Ultra)
Rate 0.14 lb ae/A (0.4 pint/A product)
Time Apply broadcast to actively growing broadleaf weeds before they are 8 inches tall. Field corn can be treated broadcast up to and including five fully exposed leaf collars (V5 growth stage).
Remarks In field corn, a high-quality adjuvant labeled for use on growing crops is recommended to improve weed control. May be applied preplant to control emerged volunteer potatoes. To control heavy populations of volunteer potatoes, a second application may be made postemergence. Only weeds emerged at the time of application will be controlled.
Caution Do not exceed 0.25 lb ae/A (0.7 pints/A) per growing season. Preharvest interval is 47 days for grazing and forage, 90 days for field corn grain and stover.
Site of action Group 4: synthetic auxin
Chemical family Pyridine
fluthiacet-methyl (Cadet)
Field corn, sweet corn for processing, and popcorn
Rate 0.0042 to 0.006 lb ai/A (0.6 to 0.9 fl oz/A)
Time Apply to corn from the two leaf (two leaf collars) to when corn is 48 inches tall or prior to tasseling, whichever comes first. See label for maximum growth stage and weeds controlled.
Remarks For use by individuals or firms certified as licensed pesticide applicators. See label for maximum weed size, usually 3 inches or less tall with the exception of velvetleaf (36 inches tall). Spray adjuvants are required for optimum weed control. Thorough coverage is essential for control of susceptible broadleaf weeds. Lower rate can be used if tank mixing with glyphosate for preplant burndown.
Caution Do not exceed 0.009 lb ai (1.25 fl oz Cadet) per season.
Site of action Group 14: protoporphyrinogen oxidase inhibitor
Chemical family Imine
glufosinate (Liberty, Interline)
Apply only to LibertyLink corn varieties
Several field corn varieties have been developed with resistance to glufosinate. Apply only to LibertyLink corn varieties. Refer to the product label for specific use directions.
glyphosate (several trade names)
Apply only to Roundup Ready corn varieties
Several field corn varieties have been developed with resistance to glyphosate. Only apply glyphosate to Roundup Ready corn varieties. Refer to the product label for specific use directions, and to the comments at the beginning of this section.
halosulfuron (Sandea)
Rate 0.5 to 1 oz ai/A (0.66 to 1.33 oz/A product)
Time Apply postemergence from spike through layby (V10-V12) stage
Remarks Do not exceed 0.75 oz ai/A per application on popcorn. Controls only susceptible broadleaf weeds and nutsedge. Always add a nonionic surfactant or crop oil concentrate if not tank mixed with other herbicides. Apply only with ground equipment. May apply up to twice per growing season.
Caution Before using, consider crop rotation plans.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Sulfonylurea
halosulfuron + dicamba (Yukon)
Rate 0.75 to 1 oz ai/A halosulfuron + 3.3 to 4.4 oz ai/A dicamba (6 to 8 oz/A product)
Time Apply postemergence from spike through layby (V10-V12) stage.
Remarks Do not exceed 0.75 oz ai/A per application on popcorn. Controls only susceptible broadleaf weeds and yellow nutsedge. Always add a nonionic surfactant or crop oil concentrate if not tank mixed with other herbicides. Apply only with ground equipment. May apply up to twice per growing season.
Caution Before using, consider crop rotation plans (see the label for details).
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Sulfonylurea
halosulfuron + thifensulfuron (Permit PLUS)
For preplant and postemergence residual in field corn
Rate 0.031 lb ai/A halosulfuron + 0.0036 lb ai/A thifensulfuron (0.75 oz/A product)
Time When used alone, Permit PLUS can be applied over the top of corn plants or with drop nozzles to 2- to 6-leaf corn (1 to 5 collars). Apply only once per season. Permit PLUS can also be applied postemergence.
Remarks Following application to foliage, allow 30 days before grazing domestic livestock, harvesting forage, or harvesting silage. Apply Permit PLUS to field corn hybrids with Relative Maturity (RM) of 88 days or more, including "food grade" (yellow dent, hard endosperm), waxy, and high-oil corn.
Caution Do not irrigate between emergence and 2-leaf stage.
Site of action Group 2: Acetolactate synthase (ALS) inhibitor
Chemical family Sulfonylurea
mesotrione (Callisto, Motif)
Do not use on white popcorn or ornamental corn
Rate 0.094 lb ai/A (3 oz/A product)
Time Apply postemergence to actively growing weeds less than 5 inches tall and when corn is in eight-leaf stage of growth or less.
Remarks Controls several annual broadleaf weeds. For field corn, always add crop oil concentrate to spray solution at 1 gal/100 gal water and 2.5% v/v of a 28% or 32% nitrogen solution or 8.5 lb/A of ammonium sulfate to 100 gal spray solution. In yellow popcorn, do not use ammonium sulfate or urea ammonium nitrate, and use nonionic surfactant instead of crop oil concentrate. Does not adequately control grasses. If corn is stressed it may be bleached temporarily. Wait at least 14 days to reapply.
Caution Do not use methylated seed oil (MSO or MSO blend adjuvants). Do not exceed 0.24 lb ai/A (7 oz/A product) per season. Do not apply mesotrione to corn treated with the insecticides Counter or Lorsban; crop injury may be severe. Do not apply within 7 days before or after applying an organophosphate or carbamate insecticide; injury may occur. See label for crop rotation restrictions. Do not apply aerially in Idaho, Oregon, and Washington.
Site of action Group 27: inhibits 4-hydroxyphenylpyruvatedioxygenase (4-HPPD)
Chemical family Triketone
mesotrione + fluthiacet methyl (Solstice)
Rate 0.0739 to 0.0931 lb ai/A mesotrione + 0.0042 to 0.0053 lb ai/A fluthiacet methyl (2.5 to 3.15 oz/A Solstice).
Time Recommended stage is spike to V5-V6 stage.
Remarks Apply with a minimum of 10 gal/A water; 15 gal/A is recommended. Use medium droplets and good pressure to penetrate weed canopy and get good coverage from top to bottom of weeds. Avoid XC (extremely coarse) type spray nozzles as coverage is not adequate for contact-type herbicides. Adjuvants (crop oil concentrate at 1% v/v + ammonium sulfate at 8.5 lb/100 gal, or nonionic surfactant at 0.25% + ammonium sulfate at 8.5 lb/100 gal) can be used, but COC provides stronger weed control. May be mixed with other labeled postemergence herbicides.
Caution Do not harvest for forage within 45 days of application. Do not harvest for grain within 70 days of application. Do not harvest sweet corn within 40 days of application. Do not apply Solstice to white popcorn or ornamental (Indian) corn. Do not apply in tank-mix with an emulsified concentrate grass herbicide unless specifically addressed on the label. Do not apply this product with fertilizer as the carrier. Do not use with methylated seed oil, as increased crop response may be seen.
Site of action (mesotrione) Group 27: 4-HPPD inhibitor; (fluthiacet methyl) Group 14: protoporphyrinogen oxidase inhibitor
Chemical family (mesotrione) Triakitone; (fluthiacet methyl) Imine
nicosulfuron (Accent Q)
Rate 0.03 to 0.06 lb ai/A (0.9 to 1.8 oz/A Accent Q).
Time Apply to corn before the 10-collar growth stage or before field corn is taller than 36 inches, or before seed corn or popcorn is 20 inches tall, and while weeds are actively growing and in the height range on label.
Remarks When not tank mixed with other herbicides, always add a nonionic surfactant or crop oil concentrate to the spray mixture. Consult the label for surfactant or crop oil specification and rates to be used alone or in tank-mixes. Apply only with ground equipment to corn that is not stressed or damaged. Use drop nozzles when field corn is over 24 inches tall. Check with seed supplier to determine crop tolerance before using on popcorn or corn grown for seed.
Caution Before using, consider crop rotation plans. Rotation crops other than corn may be very sensitive to low concentrations of nicosulfuron in soil. To avoid injury, do not apply to corn previously treated with Counter or organophosphate soil-applied insecticides such as Thimet or Lorsban. Do not apply to corn treated within 7 days with foliar-applied organophosphate insecticides such as Lorsban, malathion, or parathion, or with Basagran or 2,4-D, and do not apply any of these materials within 3 days after applying nicosulfuron, or crop may be injured. See label for further precautions and restrictions. In furrow-irrigated fields, if at least 0.5 inch of rain falls after application, do not use tail water from the first irrigation to irrigate any crop other than field corn, popcorn, or field corn grown for seed.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Sulfonylurea
pendimethalin (Prowl H2O, Satellite HydroCap, Framework)
Rate 0.75 to 2 lb ai/A, depending on soil type, and percentage of organic matter
Time Apply when corn has two to four leaves (depending on the tank-mix partner) and when weeds are no more than 2 inches tall.
Remarks Do not apply Prowl alone postemergence. Consult the label for tank-mix combinations and restrictions. Weed control is best when adequate rain or overhead irrigation is received within 7 days after application. For maximum effectiveness, wait to cultivate for least 7 to 10 days after an early postemergence application.
Caution Do not use on peat or muck soils or apply in liquid fertilizer. Do not incorporate.
Site of action Group 3: microtubule assembly inhibitor
Chemical family Dinitroaniline
primisulfuron (Beacon)
Field corn only
Rate 0.57 oz ai/A (0.76 oz/A Beacon)
Time When corn is 4 to 20 inches tall and weeds are in height range specified on label.
Remarks May make a split application. Complete all applications before corn tassels. Overhead irrigation or rain within 4 hours after applying may reduce weed control. If not tank mixed with other herbicides, always add a nonionic surfactant or crop oil concentrate to spray mixture. See label for surfactant or crop oil specification and rates when used alone or in tank-mixes.
Caution Before using, consider crop rotation plans. Rotation crops other than corn may be sensitive to low concentrations of primisulfuron remaining in the soil. To avoid crop injury, do not apply to corn previously treated with organophosphate insecticides. Do not apply primisulfuron to corn treated within 10 days with organophosphate insecticides such as Thimet, Dyfonate, Counter, or Lorsban. Do not apply any of these insecticides within 10 days before or after the herbicide treatment, or crop injury may result.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Sulfonylurea
pyraflufen-ethyl (Vida)
Field corn, glyphosate-tolerant corn, LibertyLink-tolerant corn, popcorn, seed corn, corn silage, corn stover
Rate 0.0016 to 0.0032 lb ai/A (1 to 2.0 fl oz/A Vida) + tank-mix partner or non-selective herbicide
Time VE to V4 stage of growth (approximately 12 inches tall)
Remarks Applied in-crop as an early postemergence treatment for control of broadleaf weeds in tank-mixtures with other labeled herbicides for broad spectrum weed control.
Caution Some temporary herbicidal symptoms such as leaf speckling or small discolored or necrotic spotting may appear on the crop, depending on environmental conditions, or if the crop is under stress. Do not apply postemergence to sweet corn. PHI is 50 days for silage, 90 days for grain or stover.
Site of action Group 14: Protoporphyrinogen IX oxidase (PPO) inhibitor
Chemical family Triazinone
pyroxasulfone + fluthiacet methyl (Anthem)
Rate 0.084 to 0.218 lb ai/A (5.0 to 13.0 oz/A Anthem)
Time Apply from 1-leaf through V4 stage.
Remarks Postemergence applications may be made up to V4 stage. Apply alone or in a tank-mixture to broaden weed spectrum. Where emerged weeds are present at the time of application, use appropriate weed control measures to control emerged weeds. For early preplant applications in reduced-tillage systems, use the higher rate for soil type. Requires rainfall or irrigation to activate. Soils with higher CEC require greater rates of herbicide.
Caution Do not exceed a total of 16.3 oz/A of Anthem per season. See label for rotational restrictions. Do not harvest field corn for forage for 30 days after application. Do not harvest for grain for 70 days after application. Do not harvest sweet corn forage or ears until 40 days after application. Make only one preplant/preemergence application per season.
Site of action (pyroxasulfone) Group 15: inhibits long chain fatty acid synthesis; (fluthiacet methyl) Group 14 protoporphyrinogen oxidase inhibitor
Chemical family (pyroxasulfone) Chloroacetamide; (fluthiacet methyl) Imine
pyroxasulfone + fluthiacet methyl + atrazine (Anthem ATZ)
Rate 1.126 to 2.253 lb ai/A (32.0 to 64.0 oz/A Anthem ATZ)
Time Apply from 1-leaf through V4 stage. See label for soil type, organic matter, and rate information.
Remarks Postemergence applications may be made up to V4 stage. Apply alone or in a tank-mixture to broaden weed spectrum. For early preplant applications in reduced-tillage systems, use the higher rate specified for each soil type. Requires rainfall or irrigation to activate.
Caution Restricted-use herbicide. Do not exceed a total of 39 oz/A of Anthem ATZ per season on coarse-textured soils or 70 oz/A on fine-textured soils. See label for rotational restrictions. Preplant surface applications are not recommended on coarse soils where annual rainfall exceeds 40 inches. Do not harvest field corn for forage for 60 days after application. Do not harvest for grain for 70 days after application. Do not harvest sweet corn forage or ears until 45 days after application. Make only one preplant/preemergence application per season.
Site of action (pyroxasulfone) Group 15: inhibits long chain fatty acid synthesis; (fluthiacet methyl) Group 14: protoporphyrinogen oxidase inhibitor; (atrazine) Group 5: photosystem II inhibitor
Chemical family (pyroxasulfone) Chloroacetamide; (fluthiacet methyl) Imine; (atrazine) Triazine
rimsulfuron (Resolve DF or SG)
Field corn only
Rate 0.125 to 0.5 oz ai/A (0.5 to 2 oz/A product)
Time Apply postemergence to corn up to 12 inches tall or six leaf collars but before susceptible weeds reach sizes listed on label.
Remarks Apply to field corn hybrids with a relative maturity date of 77 days or more. If weeds are present at application, use an appropriate surfactant. Allow at least 3 weeks between preemergence and postemergence applications. Rain or sprinkler irrigation will enhance control.
Caution Do not apply to field corn taller than 12 inches or six collars, whichever is more restrictive. Do not exceed 0.5 oz ai/A (2 oz/A product) per year. Consult label for re-cropping restrictions. Resolve may interact with some soil-applied insecticides.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Sulfonylurea
sethoxydim (Poast)
Poast-protected corn varieties only
Rate Maximum rate is 0.28 lb ai/A (1.5 pints/A) with a maximum of 0.56 lb ai/A (3 pints/A) per year).
Time Maximum height for quackgrass and wild proso millet control is 8 and 10 inches, respectively.
Remarks Use in Poast-protected corn varieties only. May be applied over the top. A second application is allowed 10 days after the first. Identify susceptible grasses and add 2 pints/A nonphytotoxic crop oil concentrate to improve leaf absorption. Control often is erratic on grasses stunted or stressed from drought, high temperatures, or low fertility. Resistant grasses include annual bluegrass and all fine fescues; quackgrass can be suppressed. Grass control may be reduced if applied with bentazon. Inhibits fatty acid production, cell membranes, and new growth.
Caution Do not apply to corn hybrids that are not tolerant to Poast. Do not exceed 3 pints/A per year. Preharvest interval is 60 days.
Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor
Chemical family Cyclohexanedione
S-metolachlor + atrazine + bicyclopyrone + mesotrione (Acuron)
Rate 2.15 to 2.58 lb ai/A (2.5 to 3 quarts/A Acuron)
Time Apply either preemergence or post emergence.
Remarks Acuron is a combination of the herbicides atrazine, bicyclopyrone, mesotrione and S-metolachlor plus the safener benoxacor. Rate is dependent on soil organic matter. When tank mixing or sequentially applying atrazine or products containing atrazine with Acuron to corn, do not exceed an application rate of 2.0 lb active ingredient of atrazine per acre for any single application and the total pounds of atrazine applied (lb ai/A) must not exceed 2.5 lb active ingredient per acre per year. When applied according to directions and under normal growing conditions, Acuron will not harm the treated crop. During germination and early stages of growth, extended periods of unusually cold and wet or hot and dry weather, insect or plant disease attack, carryover pesticide residues, the use of certain soil applied systemic insecticides, or improperly placed fertilizers or soil insecticides, may weaken crop seedlings. Acuron used under these conditions could result in crop injury. Where reference is made to weeds partially controlled, partial control can either mean erratic control from good to poor or consistent control at a level below that generally considered acceptable for commercial weed control. Dry weather following preemergence application of Acuron or an Acuron tank mixture may reduce effectiveness. If possible, cultivate if weeds develop. Applying Acuron postemergence to corn that has received an at-plant application of Counter insecticide can result in severe corn injury. Temporary corn injury may occur if Acuron is applied to emerged corn where organophosphate insecticides other than Counter were applied at planting. Postemergence (emerged corn) applications of any organophosphate or carbamate insecticide within 7 days before or 7 days after Acuron application may result in severe corn injury.
Caution Restricted Use Herbicide (groundwater and surface water concerns). Grazing Restriction: To avoid possible illegal residues, do not graze or feed forage from treated areas for 45 days following application. Pre-Harvest Interval (PHI): Corn (for grain, seed, or silage) may be treated up to 12 inches tall. Do not harvest forage within 60 days after application. Do not apply more than 3.0 quarts of Acuron per acre per growing year. Do not use aerial application to apply Acuron. Do not apply Acuron to sweet corn or yellow popcorn after the crop has emerged or severe crop injury may occur. Do not use Acuron on any crop other than corn (for grain, seed, or silage), sweet corn (preemergence applications only) or yellow popcorn (preemergence applications only). Do not use Acuron in the culture of white popcorn or ornamental (Indian) corn or injury may occur. Do not contaminate irrigation water used for crops or water used for domestic purposes. Thoroughly clean sprayer or other application device before using. Dispose of cleaning solution in a responsible manner. Do not use a sprayer or applicator contaminated with other materials, or crop damage or sprayer clogging of the application device may occur. If crop treated only with Acuron is lost, corn (field, seed, silage), sweetcorn, yellow popcorn, can be replanted immediately. Small grain cereals including wheat, barley and rye can be planted 4 months after application. Dry bean and potato can be planted 10 months and all other crops after 18 months. Consult label for complete crop rotation list.
Site of action (S-metolachlor) Group 15: inhibits very long chain fatty acid synthesis; (S-metolachlor) Group 5: photosystem II inhibitor; bicyclopyrone and mesotrione: Group 27: inhibits 4-hydroxyphenylpyruvatedioxygenase (4-HPPD).
Chemical family (S-metolachlor) Chloroacetamide; (atrazine) Triazine; (bicyclopyrone and mesotrione) Triketone
topramezone + glufosinate-ammonium (Sinate)
LibertyLink (LL) field corn and LL sweet corn hybrids only
Rate 0.0163 to 0.0218 lb ai/A topramezone + 0.404 to 0.54 lb ai/A glufosinate (21 to 28 fl oz/A Sinate) Do not exceed 21 fl oz/A for LibertyLink sweet corn.
Time Apply from corn emergence to 24 inch height or in V7 stage of growth for field corn or V6 for sweet corn. May be applied to LibertyLink corn up to 36 inches tall using ground application and drop nozzles. Avoid spraying into the whorl or leaf axis of corn plants.
Remarks Consult the label for tankmix partners and rotation restrictions. Apply a minimum of 15 GPA for ground applications. Apply higher spray volumes for dense canopies, large weeds, or unfavorable conditions. Do not use nitrogen solutions as spray carriers. Do not apply through any type of irrigation system. Refer to label for rotation restrictions.
Caution Do not apply to corn hybrids that are not tolerant to LibertyLink. Do not apply more than 28 fl oz/A per year for LibertyLink field corn. For LibertyLink sweet corn, do not exceed 21 fl oz/A per year. Do not apply more than once per year. Rain fastness is 4 hr. Preharvest interval is 60 days of harvesting field corn forage and 70 days of harvesting field corn grain and fodder; 50 days for sweet corn ears and 55 days for sweet corn stover.
Site of action (topramezone) Group 27: inhibits 4-hydroxyphenylpyruvatedioxygenase (4-HPPD); (Glufosinate) Group 10: glutamine-synthase inhibitors
Chemical family (topramezone) Pyrazole; (glufosinate) Phosphinic acid
tembotrione (Laudis)
Rate 0.082 lb ai/A (3 oz/A product)
Time Apply to actively growing weeds to field corn or popcorn from emergence to the V8 stage of growth.
Remarks Consult label for maximum weed size. Use a methylated seed oil (MSO) when tembotrione is used alone, or when a specific adjuvant is not listed on the label. A second application may be made to field or popcorn 14 days after the first application.
Caution Do not exceed a total of 6 fl oz/A of product per growing season. Not all hybrids of corn have been tested for herbicide tolerance. Weed control may be reduced if applied to stressed weeds or weeds that are dust covered or in the presence of heavy dew. Do not graze livestock or harvest for forage within 45 days after application. Rotation restrictions include cucurbits and dry beans (18 months) and brassica and peas (10 months).
Site of action Group 27: inhibits 4-hydroxyphenylpyruvatedioxygenase (4-HPPD)
Chemical family Triketone
tembotrione + thiencarbazone (Capreno)
Field corn, silage
Rate 3 oz/A product
Time Apply to actively growing weeds from V1 to the V6 stage of growth.
Remarks Broadens control spectrum of Laudis herbicide and adds soil residual. Consult label for maximum weed size. Use COC plus ammonium nitrogen spray additives.
Caution Do not use Lorsban, Counter, or other OP insecticides in the same season as Capreno. Not all hybrids of corn have been tested for herbicide tolerance. Weed control may be reduced if applied to stressed weeds or weeds that are dust-covered, or in the presence of heavy dew. Do not graze livestock or harvest for forage within 45 days after application. Note crop rotation restrictions on the label.
Site of action (tembotrione) Group 27: inhibits 4-hydroxyphenylpyruvatedioxygenase (4-HPPD), (thiencarbazone) Group 2: ALS inhibitor.
Chemical family (tembotrione) Triketone; (thiencarbazone) Sulfonyl-amino-carbonyl-triazolinone
thifensulfuron (Harmony GT XP)
Field corn only
Rate 0.083 oz/A Harmony GT XP
Time Apply postemergence to two- to six-leaf field corn (one to five collars, up to 16 inches tall) and after weeds emerge but before susceptible weeds reach the sizes listed on the label.
Remarks Controls broadleaf weeds. Apply to field corn hybrids with a relative maturity date of 88 days or more. Include an appropriate spray additive and either ammonium nitrate or ammonium sulfate to spray mix.
Caution Do not apply to field corn taller than 16 inches or five collars, whichever is more restrictive. Do not apply with other corn herbicides unless specified on Harmony GT XP labels or technical bulletins. Preharvest interval is 30 days for grazing or feeding forage or grain from treated crop to livestock. Not all corn hybrids or Hi-Lysine hybrids have been tested for crop safety. Do not apply more than once per season. Harmony GT may interact with some soil-applied insecticides.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Sulfonylurea
tolpyralate (Shieldex 400SC)
Rate 0.026 to 0.035 lb ai/A (1 to 1.35 fl oz/A Shieldex 400SC)
Time Apply broadcast postemergence to actively growing weeds up to 5 inches tall and to corn up to 20 inches tall.
Remarks Controls wild proso millet, several other annual grasses, and many annual broadleaf weeds. Does not control purslane. Rate is dependent on weed size. Best results are obtained when applications are made early postemergence when corn and weeds are small. Apply to corn that is less than 12 inches tall for improved coverage and best overall performance. Tankmixing tolpyralate with 0.25 to 1 lb ai/A of atrazine greatly improves control of most species, particularly common purslane. Spray additives are essential for maximum control. Methylated seed oil (MSO) is recommended (0.5 to 1 % v/v) but NIS (0.25 to 0.5% v/v) and COC (1% v/v) also can be used. UAN at 2.5% v/v will enhance performance. Spray-grade ammonium sulfate at 8.5 lb/100 gal of water may be substituted for the UAN. Tolpyralate may be used sequentially or in combination with all soil- or foliar-applied insecticides registered for use in corn.
Caution Preharvest interval is 35 days. Has not been tested on all sweet corn lines for tolerance. Rotational interval is 9 months for most vegetable crops but 18 months for sugar beets. Do not make more than 2 applications per year or more than 2.7 oz/A/year.
Site of action Group 27: inhibits 4-hydroxyphenylpyruvatedioxygenase (4-HPPD)
Chemical family Pyrazole
topramezone (Armezon, Impact)
Rate 0.0165 to 0.044 lb ai/A (0.75 to 2.0 oz/A Impact)
Time Apply postemergence to actively growing weeds 3 to 8 inches tall, in single or sequential applications.
Remarks Controls many annual broadleaf weeds and several annual grasses. See label for optimum treatment time for weeds of different sizes. Add methylated seed oil or crop oil concentrate at 1 to 1.5% v/v and urea ammonium nitrate (UAN 28 to 32%) at 2.5 gal/100 gal of water (2.5% v/v) or dry spray grade ammonium sulfate (AMS) at 2.0 to 3.0 lb/A or liquid AMS product delivering 3.4 lb/gal of AMS. Spray-grade ammonium sulfate at 8.5 lb/100 gal of water is strongly recommended when making an application in arid conditions, or during periods of hot dry weather and to larger weeds. For best performance, tank mix topramezone with 0.25 to 1.5 lb /A atrazine. Use of AMS is strongly recommended as an additive where water hardness (high mineral content) is a concern. Check the label for the full list of tank-mix herbicide partners. Topramezone may be used sequentially or in combination with all soil- or foliar-applied insecticides registered for use in corn.
Caution Do not exceed 0.044 lb ai/A (2 fl oz/A product) per growing season. Preharvest interval is 45 days. Crop rotation restrictions for snap beans and sugar beet are determined by location, and whether east or west of the Cascade mountains. Has not been tested on all popcorn and seed corn inbred lines for tolerance.
Site of action Group 27: inhibits 4-hydroxyphenylpyruvatedioxygenase (4-HPPD)
Chemical family Pyrazole
topramezone + acetochlor (Impact CORE)
For postemergence residual in field corn, seed corn, and popcorn
Rate 1.11 to 2.2 lb ai/A acetochlor + 0.0111 to 0.0221 lb ai/A topramezone (20 to 36 fl oz/A Impact CORE for soil with <3% organic matter or 22 to 40 fl oz/A for soils with 3% or greater organic matter)
Time Impact CORE herbicide can be selectively applied for control of emerged weeds and residual control of susceptible, emerged weed seedlings after crop planting. Impact CORE may be applied to field corn, seed corn, and popcorn including conventional and herbicide-resistant/tolerant corn hybrids of these corn types. Can be broadcast over-the-top spray from corn emergence up to 11 inch tall corn. Impact CORE may be used in tank mixtures of sequential applications with other products that are registered for use in corn. If Impact CORE is tank mixed with other herbicides, follow the label restrictions for the most restrictive of the tank mix products. Use adjuvants. Apply with MSO at 1 to 2 qt/100 gal of water (0.25 to 0.5% v/v) or high surfactant methylated oil concentrate (HSMOC) at 1 to 2 pt/100 gallons of water (0.125 to 0.25% v/v). Use a higher rate of adjuvant during periods of hot, dry weather and periods of moisture stress. Use of oil-based adjuvants increases the potential for leaf burn following application, however, corn development and yield are not affected. When Impact CORE is tank mixed with glyphosate products, use non-ionic surfactant (NIS) at quart/100 gal water (0.25% v/v) plus spray grade ammonium sulfate (AMS) at 1.5 to 2.5 lb/A or urea ammonium nitrate (UAN 28-34%) at 1.25 to 2.5 gal/100 gal water (1.25 to 2.25% v/v). Consult label for details on complete weed control and partial weed control. Rainfast after 4 hr. Consult label for tank mixture or sequential applications with other herbicides registered for use in corn.
Remarks Do not apply Impact CORE within 45 days of corn or popcorn harvest. Do not apply Impact CORE to corn that exceeds 11 Inches in height. Consult label for rotation restrictions.
Caution Do not flood irrigate to apply or incorporate Impact CORE.
Site of action Group 27: inhibits 4-hydroxyphenylpyruvatedioxygenase (4-HPPD) + Group 15: inhibiting very long chain fatty acid synthesis
Chemical family Triketone + chloroacetamide
topramezone + atrazine (ImpactZ)
For postemergence residual in field corn, seed corn, popcorn and sweet corn, and weed management between crops
Rate 0.016 lb ai/A topramezone + 0.333 lb ai/A atrazine (10.7 fl oz/A product) depending on soil texture
Time ImpactZ herbicide can be selectively applied to emerged weeds in all corn types including conventional and herbicide-resistant/tolerant corn hybrids. Can be broadcast over-the-top spray to small weeds in corn up to 12 inches in height. Use adjuvants. Apply with MSO at 1.5 gal/100 gal water plus UAN at 1.25 gal/100 gal or AMS at 8.5 to 17 lb/100 gal or liquid AMS equivalent. Reduce oil adjuvant rate when mixing oil-base residual corn herbicides to reduce risk of temporary foliar injury in corn. Use of NIS at 0.25% may be substituted for MSO or HSOC under conditions of tender corn foliage in early season applications. Consult label for details on complete weed control and partial weed control. Rainfast after 4 hours. Consult label for tank mixture or sequential applications with other herbicides registered for use in corn.
Remarks Do not apply ImpactZ within 45 days of corn harvest. Do not apply ImpactZ to corn that exceeds 12 Inches in height. Consult label for rotation restrictions. Do not apply more than 1 lb atrazine per acre with any application combinations. Do not graze or feed treated corn for age, silage, fodder, or grain for at least 60 days after an application of ImpactZ. Do not apply this product through any type of Irrigation system. It may be applied aerially. Following application to foliage, allow 45 days before harvesting. Do not graze or feed treated corn for age, silage, fodder, or grain for at least 60 days after application.
Caution Do not irrigate between emergence and 2-leaf stage.
Site of action Group 27 and 5: Triketone + Photosystem II inhibitor
Chemical family Sulfonylurea
topramezone + dimethenamid-P (Armezon PRO)
Rate 0.5 to 0.857 lb ai/A (14 to 24 fl oz/A product)
Time Apply postemergence to actively growing weeds 3 to 8 inches tall.
Remarks Consult label for application rate in relation to soil type. Use lower rates on coarse soils with low organic matter or low cation exchange capacity. Controls many annual broadleaf weeds and several annual grasses. See label for optimum treatment time for weeds of different sizes. Apply to corn from emergence up to 45 days prior to harvest or V8 growth stage, whichever comes first. Tank mix with atrazine (up to 12 inches tall corn) where possible to improve weed control speed and spectrum. Refer to label for crop rotation restrictions. Add 0.25 to 0.5 lb ai/A atrazine for best performance. When tank mixing with atrazine, use COC or NIS (not MSO).
Caution Do not exceed 1.15 lb ai/A (28 fl oz/A product) per growing season. Preharvest interval is 45 days. Crop rotation restrictions for snap beans and sugar beet are determined by location, whether east or west of the Cascade mountains. Has not been tested on all popcorn and seed corn inbred lines for tolerance.
Site of action (topramezone) Group 27: inhibits 4-hydroxyphenylpyruvatedioxygenase (4-HPPD); (dimethenamid-P) Group 15: inhibits very long chain fatty acid synthesis
Chemical family (topramezone) Triketone; (dimethenamid-P) Chloroacetamide
pyroxasulfone (Zidua SC)
For corn grown for grain, processing, or silage, popcorn, and sweetcorn (grown for fresh, processing or seed).
Rate 0.91 to 3.4 oz ai/A (1.75 to 6.5 fl oz /A Zidua SC)
Time May be applied early postemergence to corn for residual preemergence control of susceptible weeds. Consult the label for details.
Remarks Zidua SC may be broadcast surface applied in the fall or winter to control winter annual weeds germinating in fall. Sequential preemergence or postemergence application can be made, but do not exceed the maximum cumulative rate allowed by soil type per season. Consult the label for preplant surface application (15 to 45 days before planting) and for preplant surface or preplant incorporated application (up to 14 days before planting). Sequential application program of Zidua SC (e.g. fall application followed by spring application or sequential applications in the spring), the maximum combined rate is 2.35 oz ai/A on coarse soils or 4.43 oz ai/A on all medium-to-fine soils per year. For full-season weed control, apply a labeled postemergence treatment of Status herbicide plus glyphosate (in glyphosate tolerant field corn) as sequential component.
Caution Corn seed must be planted a minimum 1-inch deep. Before applying to seed corn, sweet corn, or popcorn, verify with your local seed company (supplier) the selectivity of Zidua SC on your chosen inbred line or hybrid in order to avoid potential injury. Do not exceed the maximum cumulative rate allowed by soil type per season. Consult the label for tank mix partners. If a labeled crop treated with Zidua SC is lost to crop failure (because of environmental factors including drought, frost, hail, etc.), the crop may be replanted. However, do not repeat application of Zidua SC after crop failure. Consult the label for the interval between Zidua SC application and the planting of rotation crops. There is no preharvest interval for soybean grain, sunflower, or cotton. Consult label for detailed information and other crop rotation restrictions.
Site of action Group 15: Very long chain fatty acid synthesis inhibitor
Chemical family Chloroacetamide