Weed Control

Eurasian Water Milfoil in North Dakota

Eurasian water milfoil (Myriophyllum spicatum) has made its way into North Dakota. A small bed of milfoil was found by a group of Valley City State University students in September 1996 in the Sheyenne River below Baldhill Dam near Valley City. This is the only site in North Dakota where it is currently known to exist. The closest that Eurasian water milfoil was documented prior to this report was central Minnesota where it first appeared in 1987 and has now spread to 79 locations within the state.

After its discovery, the Valley City class investigated further in the area, particularly downstream sites, to determine the infestation was of a larger extent. No plants were found further downstream. The main bed covered approximately 250 square feet and scattered plants were found no more than 1,500 feet downstream. The origin of the introduction into the Sheyenne River site is unknown at this time.

Eurasian water milfoil was introduced from Europe and was discovered in the eastern United States in the 1940s. This aggressive aquatic plant spreads primarily by fragmentation, i.e., if a piece of the plant is broken off it has the ability to start a new plant from that fragment. It is now found in 44 of the lower 48 states and three Canadian provinces.

This plant tolerates a wide range of environmental conditions and thus can quickly become a problem in North Dakota. It grows in a broad temperature range, tolerates fairly high salinities (15,000 parts per million), can grow in water up to 30 feet deep, and tolerates slightly acidic to fairly basic water. It can survive under the ice but can freeze out if the soil is frozen, which in North Dakota can be six months out of the year.

The potential impacts of this non-native aquatic plant are many. It has the potential to interfere with many types of water recreation, e.g., fishing, boating, water skiing, etc. It does so by forming dense mats on the surface of the water. It typically out competes and replaces native vegetation that is utilized by fish and waterfowl and can be detrimental to these populations. It also has the potential to increase mosquito populations, which breed around the canopy of plants in stagnant water created by the milfoil.

Numerous control options available: Water drawdowns and manipulations in an attempt to freeze them out, mechanical removal, chemicals, and biological control. These control methods in North Dakota have not been discussed at this time. Affected entities need to coordinate in developing a long range plan should the infestation be larger than what is currently found in the Sheyenne River.

The public can help prevent spread of the plant by thoroughly cleaning all vegetation from boating equipment (trailers, outboard motors, live wells, anchors, water ski lines), fishing equipment, diving equipment or other equipment that may have plant fragments attached. Surveys in lakes and rivers of eastern North Dakota will be conducted in 1997 to ascertain the extent of the infestation. Signs will be placed along various waters and brochures will be developed informing the public to be on the lookout for this new and potentially threatening visitor.

Small Grain Herbicides

Achieve 40DF (Zeneca) Only in Canada - Registration Expected in 1998

Affirm (United Agri Products) only in Canada

a.i.:tralkoxydim (40WDG but replaced with 80WDG)
Crops:Wheat including durum. Safe on barley.
Comments:Registered in Canada. 1998 U.S. registration expected. No crop stage restrictions for application. Use rates 0.18 to 0.24 lb ai/A). Wild oat are more susceptible than foxtail. Labeled at one rate for wild oat and foxtail control -- about $15 to $16/A. Severe antagonism with SU's and phenoxy amines but may have tank-mix options with Buctril and/or MCPA ester. Active ingredient has same mode of action as Hoelon, Dakota, Tiller, Cheyenne, and Puma. Turbo charge adjuvant included as separate container. Achieve Extra Gold is also available in Canada -- Achieve + Buctril M (Our Bronate). Problems with reduced control from aerial application.

Affinity 40DF(FMC) -- Registration Pending

a.i.:carfentrazone
Crops:Wheat and barley
Comments:Possible registration in 1997. Contact type herbicide, broadleaf weed control. Requires tank-mix with other broadleaf herbicides (2,4-D, Banvel, Buctril) for broad-spectrum and consistent weed control. Controls ALS resistant kochia.

Bromoxynil (Rhone Poulenc, Micro Flo)
Several brand names introduced in addition to Buctril and Bronate.
Bromox 2E (MicroFlo through UAP/Ostlund and Terra)
Bison (MicroFlo through Terra)
Bromox - MCPA 2-2 (MicroFlo through Ostlund)
Moxynil 2E (MicroFlo through Riverside/Terra)
A dry ester formulation (20WP) is being tested for U.S. registration.
A dry granule formulation (80WG) is also being developed.

Canvas (DuPont)

a.i.:thifensulfuron + tribenuron (Harmony Extra) + metsulfuron (Ally) - 10 acres/packet = 1/20 oz Ally 60DF and 3/20 oz Harmony Extra 75DF.
Crops:Wheat, barley and fallow
Comments:Broad spectrum broadleaf herbicide with long residual. Must tank-mix with Banvel or Buctril to control SU resistant kochia. Imparts benefits of both herbicides.

Horizon (Novartis) - Registered Only in Canada

a.i.:clodinafop
Crops:Wheat including durum and barley
Comments:Registered in Canada. Possible registration in U.S. Controls wild oat and foxtail. Less antagonism with broadleaf herbicides than fenoxaprop or Achieve.

Paramount (BASF) - Registration expected in 1998

Accord 75DF (BASF) - Registered in Canada

a.i.:quinclorac + 2,4-D acid (BAS 589).1:4 ratio or 0.125 to 0.25 + 0.5 to 1 lb/A
Crops:Wheat, fallow, noncropland
Comments:Possible registration in 1998. Labeled on foxtail, barnyardgrass, cleavers, volunteer flax, and sow-thistle. ND research shows good to excellent leafy spurge and field bindweed control. Carryover will restrict follow crops. Accord antagonizes Assert. Sun-It II only adjuvant recommended.

Peak (Ciba) 57DF

a.i:prosulfuron (0.25 to 0.5 oz 57DF/A)
Crops:Wheat, barley, oats, millet
Comments:Provides POST control of broadleaf weeds in wheat, barley, oat, rye, triticale, proso millet, and sorghum and should always be applied as a tank-mixture with another broadleaf herbicide to reduce weed resistance. Peak can be mixed with MCPA, 2,4-D, bromoxynil (Buctril, others), bromoxynil + MCPA (Bronate, others) and Banvel/SGF. Peak should be applied with a NIS. Do not apply a foliar or soil organophosphate insecticide within 15 days before or 10 days after Peak. Peak may be applied with bromoxynil, bromoxynil + MCA and MCA from 3-leaf to 2nd node. Peak may be applied with 2,4-D after tillering but prior to jointing. Peak may be applied with 2,4-D + Banvel/SGF after tillering to 5-leaf stage. A feature with Peak that is different than other long residue SU herbicides labeled in small grains (Finesse, Ally, Amber) is corn tolerance. Peak is labeled on corn outside of North Dakota in the premix Exceed. Do not rotate to crops other than field corn, grain sorghum, wheat, barley, oat, rye, proso millet, or triticale the year following Peak application.

Puma (AgrEvo) - Possible ND Section 18 in Durum in 1997

a.i.:fenoxaprop + safener
Crops:Wheat including durum and barley
Comments:Safener provides safety to spring, durum wheat, and barley. ND has applied for 1997 Section 18 for control of Treflan resistant foxtail in durum wheat. Federal label expected in 1998.

Starane (UAP) - Possible ND Section 18 in 1997

Attain (DowElanco) - IN CANADA

a.i.:fluroxypyr
Crops:Wheat (not durum) and barley
Comments:Plant growth regulator (PGR) mode of action Researched extensively for many years by DowElanco. UAP is pursuing registration in U.S. Attain in Canada is composed of 180 g/L fluroxypyr and 564 g/L 2,4-D LV ester. Limited broadleaf weed spectrum but provides excellent kochia control including control of ALS resistant kochia and most plants in the buckwheat family. Tests indicate it also controls plant growth regulator (PGR) tolerant (2,4-D, Banvel) kochia. Possible ND Section 18 for ALS resistant kochia control in barley.

Corn Herbicides

Aim 40DF (FMC) - Registration Pending

a.i.:carfentrazone
Crops:Corn
Comments:Possible registration in 1997. Contact type herbicide, broadleaf weed control. Requires tank-mix with other broadleaf herbicides (Banvel, Buctril) for broad-spectrum and consistent weed control. Controls ALS resistant kochia.

Axiom DF (Bayer) - Registration Pending

a.i.:thiafluamide + metribuzin (54.4%+13.6% DF or 4:1 ratio)
Crops:Corn
Comments:Registration expected in 1997. Soil applied, 4 to 6 weeks activity, oxy acetamide (similar to Lasso, Dual, Harness, Surpass) herbicide. Does not appear as active on North Dakota soils as competitive herbicides etc).

Balance (Rhone Poulenc) - Registration Pending

a.i.:isoxaflutole
Crops:Corn
Comments:Registration expected in 1997. Soil applied, wide spectrum grass and broadleaf herbicide, with a new mode of action carotenoid inhibitor. Excellent weed control in mid-west field trials and great plains. Weakness is giant ragweed and wild buckwheat. Requires rain for activation. However, tests show good weed control in limited rainfall conditions.

Basis Gold (DuPont)

a.i.:nicosulfuron (0.1875 oz) + rimsulfuron (0.1875 oz) + atrazine (11.5 oz)
Crops:Midpost in corn (Registered in 1996)
Comments:Contains 3 herbicides and provides excellent grass and broadleaf weed control. Labeled rate of 14 oz product/A contains 0.25 oz Accent 75DF, 0.75 oz Matrix 25DF, and 0.75 lb ai atrazine/A. Basis Gold applied to corn up to 12 inches tall controls most all annual grass and broadleaf weeds plus quackgrass. Apply with oil adjuvant at 1 to 2% v/v. NDSU research has shown greater herbicide enhancement from Accent and atrazine applied with MSO type adjuvants than NIS or petroleum oil adjuvants. Apply only to corn hybrids of 88 or more days maturity.
Basis Gold at 14 oz 89.46DF/A contains 0.25 oz 75DF/A Accent, 0.75 oz 25DF/A Matrix, and 0.76 lb ai atrazine. NDSU research has shown that good safety exists to most all crops (including small grains and sugarbeet) planted the year following atrazine applied at 0.38 lb ai/A with normal rainfall the year of application. The atrazine in Basis Gold applied at a half rate (7 oz 89.46DF/A) would be equivalent to 0.38 lb ai/A. If a half rate of Basis is used, additional Accent may need to be added to achieve adequate weed control. Applying herbicides at lower than labeled rates makes user liable for product performance and crop injury on crops planted at a shorter interval than directed on the label.

Bromoxynil (Rhone Poulenc, Micro Flo)
Several brand names introduced in addition to Buctril and Bronate.
Bromox 2E (MicroFlo through UAP/Ostlund and Terra)
Bison (MicroFlo through Terra)
Bromox - MCA 2-2 (MicroFlo through Ostlund)
Moxynil 2E (MicroFlo through Riverside/Terra)
A dry ester formulation (20WP) is being tested for U.S. registration.
A dry granule formulation (80WG) is also being developed.

Cy-Pro 4L/Cy-Pro AT 4L (Griffin)

a.i.:4L = cyanazine, AT 4L = cyanazine + atrazine Cy-Pro = DuPont's Bladex and AT = DuPont's Extrazine II
Crops:Corn (Registered in 1996)
Comments:Cyanazine is in DuPont's Bladex.

Dual II Magnum 7.65E (Novartis)

a.i.:s-metolachlor (active isomer of metolachlor)
Crops:All crops labeled with Dual.
Comments:Use rate is 62.5% of the Dual 8E rate. A gradual replacement of Dual II 8E will take place.

Exceed (Novartis) - NOT IN ND

a.i.:primisulfuron + prosulfuron (32.2% + 32.2% DF)
Crops:Corn
Comments:Broad-spectrum broadleaf weed control and a few grasses. Very long residual in high pH soils. Significant carryover occurred in Minnesota and other mid-west states in 1996. Factors that contributed to carryover are high soil pH, low rainfall, and late applications.

FulTime (Zeneca)

a.i.:Microencapsulated acetochlor (TopNotch) (2.4 lb) + Atrazine (1.6 lb)
Crops:Corn
Comments:Target no-till corn.

Frontier 6 EC (BASF)

a.i.:dimethenamid
Crops:Corn, soybean, and dry edible beans
Comments:Replace Frontier 7.5EC: lower viscosity, easier to pour, mix or pump in cool weather.

Frontier (active isomer) (BASF)

a.i.:s-dimethenamid (active isomer of dimethenamid)
Crops:Corn, soybean, and dry beans
Comments:Use rate is 55% of the Frontier 7.5EC rate.

Hornet(previously Broadstrike Plus) (DowElanco)

a.i.:flumetsulam + clopyralid
Crops:Corn
Comments:Soil applied or POST up to 24 inch tall corn. POST applications give less lambsquarters and pigweed control than soil applied.

OpTill 6EC (BASF)

a.i.:dicamba (5 lb) + dimethenamid (1 lb)
Crops:No-till corn
Comments:Preplant in no-till corn fields. Use intended only in selected parts of the mid-west. Part of a followup program with Marksman.

Touchdown 6E (Zeneca) - IN U.S. and CANADA

a.i.:Trimethyl sulfonium salt of glyphosate (6 lb ai/gal/4.5 lb ae/gallon glyphosate) (Contains the same a.i. as Roundup but common herbicide is sometimes incorrectly referred to as sulfosate).
Crops:Burndown for corn and soybean. Use also allowed on citrus, nuts, and grapes.
Comments:Previously registered only in noncrop uses. Touchdown does not contain adjuvants as Roundup Ultra. User must add surfactants and AMS to enhance weed control. Touchdown is affected by water quality and salt antagonism as Roundup.

Liberty (Link) Tolerant Corn

Liberty (AgrEvo) - IN U.S. AND CANADA

a.i.:glufosinate
Crops:Transgenic corn and soybean received registration January 17, 1997. Registration expected sugarbeet (1999), canola (1998).
Comments:Nonselective, nonresidual, contact type herbicide. New mode of action. Registered in Jan, 1997. Must be applied to small weeds due to contact type action. Liberty at 16 to 28 fl oz/A (0.2 to 0.365 lb/A) is labeled on Liberty tolerant corn for POST control of most annual grass and broadleaf weeds plus suppression of some perennial weeds. Apply Liberty EPOST or POST to Liberty tolerant corn up to 24 inches tall or with 7 collars (V7). Liberty is a nonselective, nonresidual, contact type herbicide with limited translocation. Liberty should be applied to small weeds because of limited translocation. Liberty is nonresidual which may require multiple applications or applying with a residual herbicide to control multiple weed flushes. Nonresidual nature of Liberty will allow any crop to be planted the following year. Liberty can be applied with spray grade AMS fertilizer. Refer to label for weeds controlled, application information and timing, tank-mix options, restriction. Application information, and other restrictions.
Liberty has unique mode of action which is different from Roundup and all other herbicides currently registered. Liberty in bioengineered tolerant crops will help manage current resistant weeds and will add another mode of action to prevent other weeds from developing resistance to other herbicides. However, effective and inexpensive weed control from Liberty may cause a heavy selection pressure toward any weed with increased tolerance, like velvetleaf, and others. It is unlikely for weed resistance to develop because of the lack of the resistant gene in the plant kingdom. However, as with all weed control strategies, herbicide and crop rotation should be used as a primary defense in the development of resistant weeds.

Poast (sethoxydim) Resistant (SR) CORN

a.i.:sethoxydim
Crops:SR Corn
Comments:Poast at 0.5 to 1.5 pt/A applied only to `Sethyxydim (Poast) Resistant' (SR) Corn varieties will control annual including barnyardgrass, field sandbur, foxtails, wild proso millet, and suppress quackgrass. Apply POST with oil additive at 1 qt/A to actively growing grasses 2 to 6 inches tall. Drift and off-site movement may cause injury or death to grass weeds and crops. See narrative for rates for different weeds. Grass control is reduced by tank mixtures or close interval application of POST broadleaf control herbicides. The antagonism generally can be avoided by applying the grass control herbicide 1 or more days before or 5 to 7 days after the broadleaf control herbicide.

IMI Corn

Lightning (American Cyanamid)

a.i.:imazethapyr + imazapyr (3:1 ratio or 52.5% + 17.5%)
Crops:IMI Corn
Comments:Registration expected in Early April. Excellent broadspectrum grass and broadleaf weed control. Carryover expected to be similar to Pursuit applied alone. $18 to 20/A. Lightning at 1.28 oz 70WDG/A (0.64 oz imazethapyr + 0.15 oz imazaquin) is expected to be labeled in North Dakota on IMI-corn in early 1997. Contact your dealer, NDSU Extension Service, or American Cyanamid representative for label clearance in North Dakota. Follow label directions after herbicide receives federal registration.
Lightning controls most annual grass and broadleaf weeds plus season-long suppression of perennial weeds including quackgrass and Canada thistle. Apply Lightning EPOST or POST only to IMI-corn varieties and to weeds 2 to 4 inches tall. Apply with adjuvant and liquid fertilizer. Refer to label for weeds controlled, adjuvants, application information and timing, tank-mix options, insecticide interaction, and crop rotation restrictions.
Lightning contains two imidazolinone herbicides: Pursuit and Arsenal. Pursuit is labeled on soybean and dry edible bean in North Dakota. The rate of Pursuit in Lighning is slightly below 2 fl oz/A or the North Dakota dry edible bean rate. The rate of Arsenal in Lightning is 1/100 the rate of Arsenal. Arsenal is registered on noncropland and right-of-ways for nonselective burndown and residual weed control. Carryover restrictions are from Pursuit than Arsenal due to the small amount of Arsenal in Lightning. Refer to label or table E26 for rotational crop restrictions.
Both active ingredients in Lightning are ALS inhibitors resulting in a high risk of developing ALS kochia resistance if used without herbicides of a different mode of action or using other weed control strategies.

Soybean Herbicides

Action (Novartis) - Registration Pending

a.i.:fluthiacet (proposed)
Crops:Corn and soybean
Comments:Possibly registered in 1997. A contact, non-residual type herbicide with same mode of action as Blazer and Cobra. Narrow broadleaf weed spectrum with excellent velvetleaf control and marginal to no control of most other broadleaf weeds. No grass control.

Authority Broadleaf (FMC) - NOT IN ND

a.i.:sulfentrazone (Authority) (46.9%) + chlorimuron (Classic) (9.4%)
Crops:PPI or PRE in soybean
Comments:Registration expected early 1997. Authority is a soil applied herbicide with 6 to 8 weeks residual and has the same mode of action herbicide as Blazer and Cobra. Authority controls a wide spectrum of broadleaf weeds including all pigweed species, and nightshades. Authority with Classic provides excellent control of most broadleaf weeds. However, very long soil residue of Classic prevents use in ND.

Authority One-Pass (FMC) - NOT IN ND

a.i.:sulfentrazone (Authority) + clomazone (Command)
Crops:PPI or PRE in soybean
Comments:Registration expected early 1997. Authority is a soil applied herbicide with 6 to 8 weeks residual and has the same mode of action herbicide as Blazer and Cobra. Authority controls a wide spectrum of broadleaf weeds including all pigweed species, and nightshades. Authority with Command provides excellent control of most grass and broadleaf weeds. However, long soil residue of Command prevents use in N.D.

Canopy XL (DuPont)--NOT IN ND

a.i.:sulfentrazone(Authority)(46.9%) + chlorimuron (Classic) (9.4%)
Crops:PRE in soybean
Comments:Registration expected early 1997. Authority is a soil applied herbicide with 6 to 8 weeks residual and has the same mode of action herbicide as Blazer and Cobra. Authority controls a wide spectrum of broadleaf weeds including all pigweed species, and nightshades. Authority with Classic controls most broadleaf weeds. Long soil residue of Classic prevents use in N.D.

Cover 75DF (DuPont) - NOT IN ND

a.i.:sulfentrazone (Authority)
Crops:PPI or PRE in soybean (Registration in 1997)
Comments:Authority is a soil applied herbicide with 6 to 8 weeks residual and has the same mode of action herbicide as Blazer and Cobra. Authority controls a wide spectrum of broadleaf weeds including all pigweed species, and nightshades. Use intended as part of DuPont's Reliance STS Soybean program used in the northern U.S. region. Reliance is a combination of Classic + Pinnacle.

Expert (Novartis) - Registration Pending

a.i.:oxasulfuron
Crops:Soybean
Comments:Registration expected in 1997. Short residual, SU herbicide for broadleaf weed control (no grass). Limited N.D. broadleaf weed spectrum.

FirstRate 84DF (DowElanco) - Registration Pending

a.i.:cloransulam
Crops:Soybean
Comments:Soil and POST activity. Excellent on most large-seeded broadleaf weeds like ragweeds, sunflower, and cocklebur. Poor nightshade control. Registration expected in 1997 but full use in 1998.

Matador 0.8EC (FMC) -- NOT IN ND

a.i.:quizalofop (Same as DuPont's Assure II)
Crops:Soybean

Poast (BASF) -- 30% price reduction for 1997.

Raptor (American Cyanamid) -- registration pending in U.S.

Odyssey (American Cyanamid) -- IN CANADA

a.i.:Raptor = imazamox
a.i.:Odyssey = imazamox + imazethapyr (Pursuit)
Crops:Legumes including soybean.
Comments:Herbicide similar to Pursuit except more active on grass and broadleaf weeds, no residue the following year except in low pH soils. Registration expected in 1997. Odyssey in Canada consists of 35% imazamox and 35% imazethapyr (Pursuit). Low Pursuit ratio will lessen crop rotation restrictions. Odyssey is labeled on field peas and Pursuit resistant canola in Canada.

Skirmish 25DF (FMC)_NOT IN ND

a.i.:chlorimuron (Same as DuPont's Classic)
Crops:Soybean

Other Crops

Plateau 2S (American Cyanamid)

a.i.:imazameth
Crops:Noncropland
Comments:Leafy spurge control only in noncropland and road right-of ways. NO grazing, feeding, haying is allowed.

Roundup Ready Crops (Monsanto)

a.i.:glyphosate
Crops:Roundup Ready Soybean/Corn/Canola/Sugarbeet/etc.
Comments:Registration for corn expected in late 1998.
Tolerance established in sunflower allowing preplant or preemergence application (prior to sunflower germination).
Registered for preharvest use in alfalfa allowing harvest or grazing soon after application for planting to alternate crop.

Sahara (Am Cy)

a.i.:Copack: diuron + imazapyr (Arsenal)
Crops:Noncropland (bareground)
Comments:Apply PRE or POST for total vegetation control.

Select/Prism (Valent)

a.i.:clethodim
Crops:Prism will be discontinued. AGSCO will be the only distributor with Prism. Select registration expected on all dry bean types/lentils/lupin/peas (30 day PHI), and alfalfa (30 day PHI) by July 1, 1997.
Comments:Excellent control of most annual and perennial grasses including bromes and poa annua.

Stinger (DowElanco) - Section 18 ND Labeling Pending

a.i.:clopyralid
Crops:ND Section 18 for use on canola.
Comments:Federal registration possible in 1998 or 1999.

Sythe (Mycogen)

a.i.:Pelargonic acid and related fatty acids
Crops:Burndown and noncropland. Labeled on high value crops in future.
Comments:2.5 to 5 gallons/A. Contact, nonresidual product. Active ingredients is common in nature -- grape skins have 400 ppm of ai. Claims to synergize Roundup by enhancing Roundup uptake for greater weed control.

Velpar (DuPont)

a.i.:hexazinone (75% DF or 90% SP)
Crops:Alfalfa
Comments:Possible label allowing use in North Dakota by use season 1997. Excellent annual grass and broadleaf weed control in N.D. and S.D. testing. Good to excellent quackgrass, dandelion control.

(Submitted by Richard Zollinger, NDSU Extension Service Weed Specialist)