ISSUE 8 June 21, 2001
AIM ON SOYBEAN
Aim is incorrectly listed for use as a broadcast application
in the soybean section on page 90 of the NDSU Weed Control Guide Tour. DO NOT
use Aim POST on soybean.
Aim does have a label for use in soybean ONLY as a directed
application between soybean rows. If Aim was incorrectly sprayed as a general
broadcast application severe soybean injury and death will occur.
APPLICATION TIMING ON WHEAT
Wet weather has delayed timely herbicide application in wheat.
In some cases wheat may be at or beyond the growth stage where most herbicides
can be applied. Page 12 of the 2001 ND Weed Control Guide shows the application
timing of most herbicides labeled in wheat. Only a few herbicides are labeled
for wheat at or prior to flag leaf emergence. 2,4-D, MCPA, Ally, Amber,
bromoxynil, and Starane are a few. No herbicides are registered for application
beyond the boot stage except for those on page 15 under the small grain
preharvest section. No herbicides should be applied beyond the boot stage due
interference with flowering, pollination, fertilization and kernal fill.
Ultimately, herbicides applied at this time will leave an illegal residue in the
seed and/or reduce yield.
Two herbicide with a somewhat ambiguous application window is
Discover and Puma. The end growth stage of wheat for Discover is emergence of 4th
tiller. Depending on environmental conditions this could be anywhere in the
tillering to preboot stage. Puma can be applied until 60 days prior to harvest.
Harvest is sometimes delayed for extended periods due to climatic conditions,
agronomic factors like swathing, and even farmer preference. The flexibility in
this 60 day preharvest interval allow Puma to be applied to wheat in an advanced
CALLISTO TANKMIX WITH
POST GRASS HERBICIDES
2 (ee) labels have been issued allowing Callisto to be
tankmixed with Accent,, Accent Gold, Basis Gold, and Steadfast. All label
directions and restrictions must be followed including crop stage at application
and adjuvant use.
NDSU Extension Weed Specialist
LABELS LIMIT SPRAYING FOR POST
APPLICATIONS IN CORN
Use of postemergence corn herbicides dictates knowing when to
apply the herbicides. Limitations on harvest intervals between when you spray
and when you may harvest must also be kept in mind. Remember the label will
provide you all of this information. Much spraying has been occurring in the
Valley over the last two weeks. Keep in mind that many herbicides work better
under the humid conditions we have been experiencing recently. Also, cool nights
will slow down the metabolism of the herbicides through the corn plants and may
limit the harmless breakdown of the absorbed chemicals in the corn plant causing
weakening or stunting of corn in some cases on certain herbicide modes of
activity. As corn gets taller, remember to be careful with sprayer nozzle
positioning for those herbicides that can be used later by spraying with drop
nozzles. Morning spraying can increase herbicide activity (or cause slight corn
injury especially after cold nights) by the morning dew on the corn plant along
with the upright leaf structure of the plant allowing chemical to funnel and run
directly down into the corn plant whorl. Some general application restrictions
- Bromoxynil may be applied to corn up until tasseling;
- Bromoxynil + Atrazine may be applied on corn up to 12
- Basagran may be applied on corn at all stages, but weed
size limits use;
- Atrazine + oil may be applied before corn is 12 inches
- Bladex/Cy-Pro may be applied up to corn in the 4-leaf
- Sencor can be applied up to tasseling;
- 2,4-D can be applied up to tasseling but use drop nozzles
once corn is over 8 inches tall and remember to use amine formulations when
temperatures approach 80 to 85 F to limit chemical movement;
- Shotgun can be applied from spike to the 4th-leaf corn
stage (up to 8 inch corn) or as a directed spray to the ground at the
5th-leaf or 8-12 inch corn;
- Banvel/Clarity can be applied up to 15 days before
tasseling, but use drop nozzles once corn is 8 to 36 inches tall (and if
soybeans are nearby and over 10 inches tall or have begun to bloom, don't
apply either herbicide to corn over 24 inches-this also applies to
Celebrity, Celebrity Plus and NorthStar);
- Banvel/Clarity + Atrazine can be applied up to 5-leaf corn;
- Distinct can be applied to corn at 4-16 inches tall (up to
6 collar or less corn);
- Stinger can be applied on corn up to 24 inches tall and
watch weed size limitations;
- Hornet can be applied to corn up to 24 inches tall;
- Curtail can be applied to corn up to 8 inches tall or once
4 visible leaf collars are showing;
- Tough can be applied to corn up to 68 days prior to
- Aim can be applied to corn up to 12 inches tall (or corn up
to 8 collars);
- Callisto can be applied to corn up to 30 inches tall;
- Permit can be applied to corn at spike to layby;
- NorthStar can be applied to corn from 4-36 inches but use
drop nozzles on 20-36 inch corn;
- Scorpion III can be applied to corn up to 8 inches tall;
- Basis can be applied from the spike to the 4 leaf (or 2
collar) stage in corn;
- Basis Gold can be applied to corn up to 12 inches tall or
prior to 6 collars in corn;
- Steadfast can go on corn up to 12 inches tall (6 collars);
- Accent can be applied on corn up to 20 inches tall or with
6 or fewer collars (at 20-36 inch corn, use drop nozzles);
- Accent + Atrazine can be applied on corn up to 12 inches
- Accent + Banvel/Clarity can be applied to corn up to 8
inches tall broadcast and from 8 to 24 inches with drop nozzles;
- Celebrity Plus can be applied on corn up to 16 inches or
with 6 or less collars and applied with drop nozzles from 16 to 36 inches;
- Accent + Bromoxynil can be applied on corn up to 20 inches
or 6 collars and with drop nozzles from 20 to 24 inches;
- Accent + Hornet can be applied up to 20 inches or 6 collars
on corn and with drop nozzles from 20 to 24 inches;
- Accent Gold can be applied on corn up to 20 inches or with
6 or less collars and with drop nozzles from 20 to 24 inches;
- Leadoff can be applied on corn up to 8 inches tall.
LABELED LIMITS FOR POST APPLICATIONS
The following label limits are approved for post applications
in soybeans. Remember to carefully consider the weather and crop conditions
before making a herbicide application.
- Basagran is restrictive only on weed size in soybeans.
- Ultra Blazer can be applied to soybeans with 1 to 2
trifoliates (weed 1-4 inches tall).
- Cobra can be used on soybeans with 1 to 2 trifoliates
(weeds 2-6 leaves).
- Flexstar is restrictive only on weed size (2-4 leaf) and
- FirstRate apply up to 50% soybean flowering (weeds up to 10
inches tall or 8 leaves).
- Harmony GT apply to fully expanded first trifoliate on
soybeans but 60 days before harvest.
- Pursuit spraying can begin after the first trifoliate,
prior to flowering.
- Pursuit + Basagran use after the first trifoliate, prior to
- Pursuit + Harmony GT apply to the first trifoliate to prior
- Pursuit + Flexstar apply to the first trifoliate to prior
- Pursuit + Cobra apply after the first trifoliate, prior to
- Raptor use after the first trifoliate, prior to flowering
(weeds at 2-6 inches).
- Raptor apply at the first trifoliate up to flowering (weeds
- Raptor + Flexstar apply at the first trifoliate up to
flowering (weeds 2-6 inches).
- Raptor + Cobra apply at the first trifoliate up to
flowering (weeds 2-6 inches).
- Rezult apply from emergence to 30 days prior to harvest.
- Assure II can be used up to pod set (grass weeds 2-6 inches
- Fusilade DX can be applied prior to flowering (grass weeds
2-4 inches tall).
- Fusion use prior to flowering (grass weeds should be 2-6
- Poast is restrictive only on weed size (grass weeds up to 8
- Select or Prism are restrictive only on weed size (annual
grass 2-6 inches tall; quackgrass 4-12 inches tall).
Extension Crop Production Specialist