(upbeat music)
-: I'm going to discuss a project
where we want to control this Palmer amaranth,
which is resistant to atrazine, glyphosate
and ALS inhibiting herbicides,
just by using a post emergent herbicides,
applied early post or late post.
And this is not under ideal condition,
but under worst case scenario,
for example if some grower was not able
to apply pre-emergence herbicide,
then what are the options for controlling
this resistant Palmer in corn?
So that was the main objective here.
We selected few herbicides applied early post-emergence
and then in other set of treatments,
they were applied late post-emergence.
We planted this corn on May 12th,
early post-emergence herbicides were applied on June 19th
and late post-emergence herbicides
were applied on June 23rd.
So just to clarify, early post and late post herbicides
were applied in different plots.
We would want it to see how best a post-emergence herbicides
can control when Palmer amaranth
is somewhere less than six inches tall
in early post-emergency application
versus when they are applied late post-emergence herbicides
were applied when Palmer amaranth
was somewhere between eight to 12 inch tall.
So that was the main objective of this project
to evaluate the efficacy
of post-emergence herbicides applied early post-emergence,
or late post-emergence.
So for example, this is untreated check means no herbicides
were applied and naturally it is a full off Palmer amaranth
as well as we also have some foxtail,
it's like yellow foxtail and giant foxtail at this site.
So you are seeing a combination of Palmer amaranth
and foxtail species when you don't control
these weeds at all.
This is our weed-free plot means we want to keep
this plot without any weed species.
We also applied herbicides Acuron was applied pre-emergence,
and then it was followed by DiFlexx
in a tank mixture with a Liberty.
DiFlexx is Dicamba-Based herbicides
and it has great efficacy
for controlling glyphosate resistant weeds
like Palmer amaranth or waterhemp.
So this plot is really very good looking
because there was no early season competition.
And if you will see this plot versus this plot,
you will find a pretty great difference in corn height,
because Pre-emergence herbicides was applied here
and no herbicide was applied in this plot.
In this plot, no pre-emergence herbicide was applied
and only glyphosate was applied when corn was about five
to six inch tall.
And as I mentioned earlier,
this Palmer amaranth at this period
is very highly resistant to glyphosate.
So even higher rate of glyphosate
would not control this Palmer.
And in fact of some of Palmer has just started flowering
in this field because this population
is very highly resistant
to glyphosate up to like 37 X means,
even if you will apply 37 times more rate
than label rate, you will get some level of control.
In this plot Liberty,
which is a contact herbicide was applied
there early post-emergence
and there was no any pre-emergence herbicide was applied.
So it has provided some level of control,
but Liberty has no any residual activity.
So you are now seeing some Palmer amaranth
has started emerging now.
And that is because --
And this is why Palmer amaranth is difficult to control
because it can emerge throughout the growing season.
For example, this Palmer amaranth may
have started emerging before the month,
and this is a new little seedling of Palmer amaranth
that just may have emerged before a couple of days.
So that's why Palmer amaranth is difficult to control
because it can emerge throughout the growing season.
And in this plot particularly,
we applied Liberty before about couple of weeks,
so it has provided good control,
but now Liberty has no any residual activity.
So now it is a, some new Palmer amaranth is coming up.
DiFlexx DUO in this plot
was applied early post-emergence when Palmer amaranth
was less than six inches tall,
and it has provided a decent level of control.
And DiFlexx DUO is actually a good combination
of a Dicamba with one more herbicide,
so it can provide broad spectrum weed control.
You are seeing a good level of control of Palmer amaranth
as well as a foxtail grass species.
And these are some good symptoms of DiFlexx DUO
because it is a Dicamba-Based herbicide
as well as you are also seeing some bleaching
on the top of Palmer.
Status is one more Dicamba-Based herbicides
that can be applied in corn.
It was applied early post-emergence when a Palmer amaranth
was less than six inches tall,
and it has provided a decent level of control --
(clears throat)
This are some typical symptoms
of Dicamba-Based herbicides on Palmer amaranth.
They are twisting, and this mainstem is also twisting.
The leaves are also twisting,
and this plant will die maybe after about a couple of weeks
because Dicamba is a systemic herbicide
and it takes time for the susceptible broadleaf weed species
to completely kill.
Treatments I'm going to discuss now
were applied only late post-emergence
under worst case scenario,
what will happen or what kind of control we can achieve,
if we use only post-emergence herbicides very late
in the season, so which is not very ideal,
but under rescue conditions is there any herbicides
that can provide effective control of Palmer amaranth,
which is resistant to atrazine, glyphosate
and ALS inhibiting herbicides?
So now when all the herbicides were applied
when Palmer amaranth was somewhere
between eight to 12 inches tall.
For example, Liberty, which is a good contact herbicide,
it was applied at the maximum label rate
of 43 ounces per acre,
and it has provided a decent level of control.
And just to clarify there was no any pre-emergence herbicide
was applied in this plot.
And because Liberty is a broad spectrum herbicide,
it has also provided a good level of control of foxtail.
For example, yellow in a giant foxtail
that we do have in this plot.
DiFlexx was applied the late post-emergence
when Palmer amaranth
were somewhere between eight to 12 inch tall,
and it has provided good level of control
of Palmer amaranth
although it was applied relatively late in the season.
The only thing because, DiFlexx
is a Dicamba-Based herbicide.
So we are seeing some grass weeds,
and it can be controlled by applying glyphosate type
of grass killing herbicides.
But this is also one of the best herbicides to apply,
if you want to consider any rescue herbicide,
pour controlling Palmer amaranth late in the season.
Armazon PRO was applied late post-emergence
in this plot, when Palmer amaranth
was somewhere between eight to 12 inch tall.
And it has provided some level of control,
but Palmer amaranth was too tall
to be effectively controlled.
You can still see some symptoms of this herbicide,
for example, this is HPPD inhibiting herbicides.
So this type of bleaching,
you can see white color on Palmer amaranth.
These are typical symptoms of a herbicide
like Armezon PRO,
which has Topramezone,
an HPPD inhibiting herbicide.
So not only on broadleaf weed species,
but it can also provide a control of grass weeds,
for example, here this foxtail species,
it was too tall to be effectively controlled
at the time of application,
but are seeing some symptoms of this herbicide
on this grass species.
So the take home message from this project is number one,
we can not achieve a very high level of control
by using only early post or late post-emergence herbicides
and the best thing we can do is under rescue condition,
you can use certain herbicides such as Liberty
or Dicamba-Based herbicides,
such as DiFlexx or DiFlexx DUO,
that can provide decent level of control
of Palmer amaranth,
which is resistant to atrazine, glyphosate,
and ALS inhibiting herbicides.