ndsucpr_L_sm_W.jpg (13414 bytes)
weeds_Logo_Lg.jpg (6562 bytes)


ISSUE 4  MAY 27, 1999

 

HERBICIDES FOR WEED CONTROL IN CANOLA

    The list of herbicides labeled for use in canola has significantly increased for the 1999 production season. Preplant_incorporated herbicide choices include trifluralin (e.g. Treflan) at 1 to 2 pt or 5 to 10 lb per acre and
Sonalan (Section 18 emergency exemption) at 1.5 to 3 pt or 5.5 to 11.5 lb 10G per acre. Post-emergence
grass herbicides include Assure II at 8 to 10 fl oz per acre and Poast at 0.5 to 1.5 pt per acre. Section 18 label
allow the use of Stinger postemergence applied at 0.33 to 0.5 pt per acre for control of 4-to 6-inch tall
Canada thistle and perennial sowthistle. Stinger also will provide good to excellent control of common
cocklebur, marshelder, common ragweed, annual smartweed, and sunflower. Section 18 label allow the use
of Muster postemergence applied at 0.3 oz per acre will control wild mustard in seed-production fields of
canola. Section 18 label allow the use of Herbicide 273 at 2 to 3 pt/A postemergence for control of wild
buckwheat and annual smartweed.

    Section 18 labels allow the use of Raptor on IMI-tolerant canola, Liberty on Liberty-resistant canola,
and Roundup on Roundup-Ready canola. Raptor applied at 4 fl oz per acre prior to canola bloom will
control most annual broadleaf and grass weeds. Liberty applied at 34 fl oz per acre to cotyledon- to
early-bolting canola will control annual broadleaf weeds, and suppress or control annual grass and perennial
weeds. Roundup Ultra applied at 1 pt per acre at canola emergence to bolting will control many annual
weeds and a second application of 1 pt per acre before canola bolts will aid in control of annual broadleaf
and perennial weeds.

    Refer to herbicide labels and NDSU Extension Service circular W_253 '1999 ND Weed Control Guide'
for required details. Growers must have Section 18 labels in their possession during herbicide application.

Greg Endres
NDSU Extension Area Specialist
Carrington R&E Center
gendres@ndsuext.nodak.edu

 

POSTEMERGENCE WEED CONTROL OPTIONS IN FIELD PEA AND LENTIL

    Field pea and lentil are not very competitive with weeds and spraying early postemergence is very important.
Most broadleaf herbicides require small weeds and small peas or lentils to reduce the injury potential to the
crop. Avoid spraying broadleaf herbicides when temperatures exceed 85 F or when the peas or lentils are
under heat/drought stress. Keep in mind with postemergence weed control options for field pea and lentil that
many herbicides might unfamiliar to a grower and always follow the label directions and do not cut the rate
of the specific herbicide.

 

HERBICIDE OPTIONS IN LENTILS

    Sencor: Common rate 1/6 to 1/4 lb/ac. Sencor is used for broadleaf weed control and will provide excellent
control of wild mustard, field pennycress, shepherdspurse, and lambsquarters. Sencor will provide good control
of small wild buckwheat, kochia, and wild sunflower. One post application should be made per season. Crop
injury may result if the crop is under stress conditions caused by cold weather. Apply when weeds are small
(less than 2 inches in height or diameter) and before the crop is 6 inches tall.

    Assure II: 8 oz/ac for annual grass control; 10 oz/ac for suppression of quackgrass. The addition of 1 gallon
of petroleum oil per 100 gallons of water is recommended.

    Poast: 0.5 pint/ac for green foxtail, 3/4 - 1 pint/ac for volunteer grain, wild oat and yellow foxtail, split
applications of 1.5 pints/ac followed by 1 pint/ac for suppression of quackgrass. The addition of modified seed
oil at 1.5 pints/ac or Dash at 1 pint/ac is recommended to enhance grass control.

 

HERBICIDE OPTIONS IN FIELD PEA

    Basagran: 1 to 1.5 pints/ac for broadleaf control. Contact herbicide, needs 15 to 20 gallons of water
per acre. The addition of modified seed oil at 1.5 pints/ac or Dash at 1 pint/ac will improve control. For hard
to control broadleaves, such as, kochia or wild buckwheat or for the suppression of Canada Thistle, split
applications of 1 pint/ac, seven to ten days apart in needed for consistent control. Apply when peas have
reached the 3 leaf stage or 4 nodes (approximately 2 to 4 inches in height). If applying split applications, the
second application can be safely applied to taller peas (6 + inches).

    Pursuit: 0.72 oz/ac for broadleaf control, will give suppression of black nightshade.. The addition of
non-ionic surfactant at 1 quart per 100 gallons of water will improve control. Pursuit can be applied to peas
from the first trifoliate to prior to bloom. Pursuit is an ALS inhibitor and will not control ALS resistant kochia.

    Chiptox (MCPA sodium salt), MCPA (Certain Brands), Thistrol (MCPB), Rhomene: 0.5 to 1 pint/ac for
good control of wild mustard, redroot pigweed, and other broadleaf weeds. Apply to 4 to 6 inch pea vines.
Peas might be slightly injured and will usually recover. These herbicides have the most potential for crop injury,
especially when applied to taller peas (6 + inches). The potential of injury increases when temperatures exceed
85 F or when the peas are under heat/drought stress.

    Sencor: common rate 1/6 to 1/4 lb/ac. Sencor is used for broadleaf weeds and will provide excellent
control of wild mustard, field pennycress, shepherdspurse, and lambsquarters.. Sencor will provide good control
of small wild buckwheat, kochia, and wild sunflower. One post application should be made per season. Crop
injury may result if the crop is under stress conditions caused by cold weather. Apply when weeds are small (less
than 2 inches in height or diameter) and before the crop is 6 inches tall.

    Assure II: 8 oz/ac for annual grass control; 10 oz/ac for suppression of quackgrass. The addition of 1 gallon
of petroleum oil per 100 gallons of water is recommended.

    Poast: 0.5 pint/ac for green foxtail, 3/4 - 1 pint/ac for volunteer grain, wild oat and yellow foxtail, split
applications of 1.5 pints/ac followed by 1 pint/ac for suppression of quackgrass. The addition of modified
seed oil at 1.5 pints/ac or Dash at 1 pint/ac is recommended to enhance grass control.

    Assure II and Poast should not be tankmixed with any broadleaf herbicide or reduced grass control can
occur. Reduced grass control can be avoided by applying Assure II or Poast at least 1 day before or 5 days
after application of a broadleaf herbicide.

 

HERBICIDES CLEARED FOR CHICKPEA

    There were over 3,000 acres of chick peas (garbanzo bean) raised in western North Dakota last year.
Acres of chickpeas in North Dakota this year could exceed 10,000. Weed control in chickpea is very
important. There are many herbicides labeled in chickpea. Contact the specific herbicide label for specific
use information.

    Glyphosate (Roundup Ultra, private labels): Preplant or anytime prior to crop emergence.

    Fargo: Preplant incorporated or preemergence incorporated for wild oat control.

    Trifluralin: 1 to 1.5 pt/A. At these rates, Trifluralin will give excellent control of foxtails, however will
only give suppression of broadleaf weeds. Poor wild mustard control.

    Sonalan: 1.5 to 2 pt/A HFP or 5 to 7.5 lb/A 10 G. The 2 pint/A rate of HTP or 7.5 lb/A rate of 10G
will give better control of hard to control broadleaf weeds such as, kochia and Russian thistle than
Trifluralin. Poor wild mustard control.

    Prowl: 1.2 - 3.6 pt/A. A minimum of 2.5 pints/A is needed to give good control of hard to control
broadleaf weeds such as, kochia. Prowl at the rates of 2.5 to 3.0 pints per acre will be the best option for
the control kochia in chickpea. Poor wild mustard control.

    Dual II, Dual II Magnum: 2 - 3 pt/A Dual II, 1 - 2 pt/A Dual II Magnum. Will give good control of
foxtails, barnyardgrass, and redroot pigweed. Poor wild mustard and wild oat control.

    Assure II: 8 to 10 fl oz/A. Postemergence herbicide for annual grasses and quackgrass. The 10 fl. oz/A
rate is needed for quackgrass.

    Poast: 0.5 to 1.5 pints/A. Postemergence herbicide for annual grasses.

    Select: 6 to 8 fl. oz/A. Postemergence herbicide for annual grasses and quackgrass. The 8 fl oz/A rate is
needed for quackgrass.

    Keep in mind that there are no postemergence broadleaf herbicides currently labeled in chickpea. A Section
18 Emergency Exemption is pending for the use of Tough herbicide in chickpea in North Dakota for 1999. Tough
would be applied early postemergence in chickpea for annual broadleaf weeds such as, kochia and Russian
thistle. Pursuit is not labeled due to that chickpea is similar in sensitivity to injury as lentils. Basagran is not
labeled on chickpea due to the injury potential.

Kent McKay
Area Agronomist
North Central Research Extension Center, Minot
kmckay@ndsuext.nodak.edu

 

AERIAL APPLICATION OF STINGER ON SUGARBEET

    A 24 (c) Special Local Need registration for aerial application of Stinger on sugarbeet in North Dakota
and Minnesota was received in 1994 and remains in effect. The general Stinger label states "Do not apply
by aircraft" so Stinger should not be applied by aircraft to crops other than sugarbeet.

Alan Dexter
NDSU/U of MN Extension Sugarbeet Weed Specialist
adexter@ndsuext.nodak.edu

 

CONTROL GRASSES AND THISTLES IN CORN AND SOYBEANS

    Canada thistle, quackgrass and foxtails are up and growing due to the ample moisture in corn and soybean
fields this spring. A combination of cultivation and chemical weed control may help integrate management of
Canada thistle and foxtail. Chemical control of quackgrass can control infestation and limit this aggressive weed
that can quickly crowd out crop plants.

    Cultivate Canada thistle as soon as possible and use a post application of Stinger or Distinct or atrazine,
Basagran, Banvel or Clarity or 2,4-D amine to suppress growth of the weed in corn. In soybeans, post-apply
Basagran or Rezult to stress the weed plants and follow with additional cultivation or a second application of
Basagran 10 to 14 days after the first chemical application. Remember the location of heavy infestations which
are not suppressed this season so that Roundup Ultra, Stinger, Curtail, 2,4-D, Banvel or Clarity alone or in
combination can be used in the fall prior to a killing frost to any remaining Canada thistle.

    Quackgrass spreads rapidly due to rhizomes. Broken rhizomes quickly form new plants making mechanical
control impractical in both corn and soybeans. For quackgrass problems in corn, consider the use of nicosulfuron
Accent, Accent Gold or Celebrity. However, Accent Gold should only be used in corn with a maturity rating
greater than 88 days. In soybeans, several chemicals can be used. In heavy quackgrass, one of the following
chemicals can be used in two split applications for good control: Assure II, Fusilade DX, Fusion, Poast; and,
Select. Spraying quackgrass between the 4-leaf and up to the 10-inch stage with any of the split application
chemicals will work best for control.

    The foxtails, both green and yellow, have begun emerging this last week in most locations throughout the
Valley. Control of foxtails in corn with cultivation and post herbicides can mean the use of Accent, Accent Gold
or Celebrity; atrazine plus oil; or, Basis, Basis Gold. In soybeans, consider the use of Raptor; Assure II; Fusilade
DX or Fusion, Poast or Select.

    Good use of control measures on troublesome weeds such as Canada thistle, quackgrass and foxtails can
prevent weed seed development and lead to decreases in the weed seed bank on fields.

Denise A. McWilliams
Extension Crop Production Specialist
dmcwilli@ndsuext.nodak.edu

 


cprhome.jpg (3929 bytes)topofpage.jpg (3455 bytes)tableofcontents.jpg (4563 bytes)previous.jpg (2814 bytes)next.jpg (1962 bytes)


a