Herbicides
165
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Safety - page 25 • First aid - page 33 • Resistance management - page 41
Canada Thistle Control: Summerfallow and Post Harvest
Weed stage
Acid equivalent in
grams active
ingredient per acre
Remarks
Control of Canada
thistle at the rosette
stage (summerfallow)
Rosettes at least
15
cm in diameter
360
Conduct summerfallow tillage as usual and perform the last
tillage operation between July 15 and August 1. Allow thistle
to re-grow for a minimum of 5 weeks until they are 15 cm in
diameter and majority of them are in a rosette stage. Allow 10
or more days after treatment before tillage. Treatment after a
mild frost is possible provided leaves are green and plants are
actively growing.
Control of Canada
thistle: post-harvest
stubble treatment
Bud stage or
beyond
648 - 1000
Allow 20 to 25 cm of new growth before application. Thistles
must be sprayed at least 2 weeks prior to killing frost. Straw
should be removed or evenly spread to allow for proper regrowth
and spray coverage. Heavy frost prior to treatment may
decrease control.
Allow 5 or more days after treatment before tillage.
Registered Tank Mixes: Canada Thistle Control
•
Glyphosate + Banvel II (0.12 L/acre)
Dandelion Control: Prior to Seeding or After Harvest
For best results, apply up to and including dandelion bloom.
Dandelion stage of growth gram A.I /acre
Remarks
Less than 15 cm rosettes Greater than 15 cm rosettes
360
540 - 720
Allow 3 or more days after treatment before tillage for all rates. Use
the higher rate when infestations are heavy.
Alfalfa Control (Fall Treatment)
Staging
Rate a.i. per acre Remarks
Early bud to full bloom
(
fall application only)
540 - 720
Use high rate when alfalfa populations are high or when grass infestation is
heavy. Allow at least 5 days before tillage. Apply in 23 - 135 L/acre water.
Registered Tank Mixes for Alfalfa Control (Fall and Spring)
The addition of 2,4-D may improve alfalfa control in situations where control may be more difficult to obtain,
such as in minimum tillage systems where populations are heavy and with spring applications.
Tank mixture name Acid equivalent in grams active
ingredient per acre
Remarks
Glyphosate + 2,4-D
Glyphosate: 360 - 720 g a.i./acre +
2,4-
D: 0.49 - 0.97 L
For spring applications, use only the low rate of 2,4-D
(
i.e., 0.49 L/acre) and recommended rate of glyphosate.Only cereal
crops not underseeded to legumes may be planted
following spring applications of this tank mix, and a 14-day interval
between application and planting is required.
Spot treatment (in-crop) of perennial weeds in wheat, oat, barley, corn, soybean forage legumes and forage grasses:
Glyphosate may be applied for the control of Canada thistle, quackgrass and other perennial weeds (absinthe, blue
grass spp., smooth bromegrass, cattail, curled dock, field bindweed (bloom stage or beyond), hemp dogbane, hoary
cress, poison ivy, purple loosestrife, perennial sow-thistle, and yellow nutsedge in forage crops, barley, wheat, oats,
soybeans and legumes, including seed production. Treatments may be made up to heading of small grain, initial
pod set on soybeans and legumes, silking of corn, and emergence of seed heads. The crop in the treated area will
be killed. Avoid drift beyond the treated area. Application can be made using a boom sprayer, knapsack, or high
volume equipment. Applications should be made using the same rates and at the same growth stages as listed in the
quackgrass, Canada thistle and other perennial weed control tables.
Glyphosate (cont’d)