WPT University Place: Managing Corn Disease in Wisconsin


– Up next we have Damon Smith. Damon is an assistant professor and Extension plant pathologist
at UW-Madison. Damon’s responsibilities
include research efforts that focus on improving
our understanding
of the epidemiology of plant pathogens, in order
to develop better management recommendations for the
sustainable management of field and forage crop diseases. (exhaling) That’s
pretty intense. All right, Damon is a native
of western New York state. He earned his Bachelor’s
degree in biological sciences at the State University of
New York college at Geneseo. How’d I do?
– [Damon] Nice. – All right, and his Masters
and PhDs degrees from North Carolina State University. Prior to Damon’s
appointment at UW, he was an assistant
professor at Oklahoma State. – All right. Yes, that’s intense, and
I’m a pretty intense guy. You guys probably
know that already, so. I guess I gotta do this close,
because you can’t hear me. It’s the end of the day, right? I know I’m standing
between you and the beer, afterwards here. So, I’m going to try to keep
this moving along for ya, and, we’ll jump right in to
talking about some diseases. I think y’all will agree,
the last couple of years, the two big ones in corn
for us, here in the state, are Northern Corn Leaf
Blight and Goss’s Wilt. I know there’s some
other minor diseases, we talk about eyespot and
some of these other things that move in, but I think
if we had to classify and pick out the top
players here, these are the ones that we’re looking at. So, I want to take some time,
my, from what I’ve learned over the past couple of seasons,
I think, we’ve got a lot of issue in terms of just trying
to tell the difference between these two diseases. I just want to take
some time just to kind of tease this out, and then we’ll look
actually at some fungicide data over the last couple
of years here in the state. So, Goss’s Wilt, as Ned
Phipps talked about earlier, this is sort of a reemerging
issue for us here, especially in Wisconsin. It was discovered here
25 or 30 years ago. So, it’s not an unusual
thing to find here, but we sorta, were
able to manage it. And I’ll talk about
why maybe we’re seeing some resurgence here. It is caused by a bacterium. So Clavibacter michiganensis,
subspecies Nebraskensis, that’s a lot of
words in Latin there, and if you’re like
me, I hate Latin. So we’ll just call it the
Goss’s Wilt pathogen, ‘kay. So, it is often confused with
Northern Corn Leaf Blight because we get these really
long, sort of broad lesions across the leaf, ‘kay? And so, you can see some of
this here in this upper slide, again in the lower slide there. It can have two phases,
there’s the wilt phase, and the leaf blight phase. I think you’ll agree with me,
that, what do we see most? The leaf blight phase,
and that’s really
what confuses a lot of us, and it is found
throughout the Midwest here. Some, common phases here, or things that we
see in the leaf blight phase we see, we
see these freckles. So how many are familiar
with the freckles? Some of you have seen these. Some of you are awake and
listening to me, so that’s good. So, when you don’t see the,
when you don’t have these held up to the back light, these freckles look dark. Scattered throughout
this, bleached lesion. And then if you hold
these up to the light, and get some back
light behind them, they will often, change to
being translucent in color. This is really,
tell-tale sign here. We put a lot of merit,
actually, when we’re trying to diagnose this in the
field, on these freckles. The other thing
you can do is grab a piece of these leaves here,
and you can actually incubate these in a, in a plastic Ziploc
bag with a wet paper towel, and sometimes, if you’re lucky, you’ll get the bacterium
actually oozing
out of the leaves. So that’s a trick. That doesn’t always happen, but that is something that
sort of helps you get, to where you need to be. The other thing is, is that, the lesions typically
will be much longer than a Northern Corn Leaf
Blight lesion. You know, the longest Northern
Corn Leaf Blight lesions we typically see are
maybe about six inches. Now what the caveat there is those lesions can coalesce. And you’ll get a larger lesion
from the conglomeration of those, but no single lesion
will get as large as we see with Goss’s Wilt
in a lot of cases. The other, thing to kind
of step back and look at, is the pattern in the
field that you see these things occur, because
that’s really important when you’re trying to tell the
difference between Goss’s and Northern Corn Leaf Blight. A lot of times, with Goss’s,
we’re seeing the symptom actually starting on the upper
portion of the plant. Why is that happening? Well, this is a bacterium that’s actually getting inside the
plant, it’s disrupting the water conducting elements
in the plant. And so, the farthest zones
from the root system, obviously are the
upper leaves, right? And so those are the
first things that
get starved by water, and so a lot of
times, we start to see those symptoms
appear at the top. Where’s Northern Corn Leaf
Blight typically start? Those of you who scout? Down lower in the canopy, right? So northern corn, we
typically see it start low, and then it sort of progresses
up to the top of the plant. There are sometimes
exceptions to that rule, but generally speaking, that’s
what we see a lot of times. So the red zone
here on this map, this sort of gives
us the historical, what we might call
the high risk zone. So, you’ve probably all
seen data to Nebraska. That’s sort of a hot
zone, and of course, there’s a lot of
irrigated corn there. And so, there’s a lot
of work being done in that area of the
country on Goss’s Wilt. So we sort of extrapolate
some of the management from those areas out
to the other areas. Now in about 2010, 2011,
we started to see, again, a reemergence of this issue
here in the Midwest, and so, you’ll see this sort of orange
blob here on the map starting to stretch out, and that’s
the resurgence zone. This isn’t to say that
this is new here. Again, we found it
25 or 30 years ago, but it’s sort of
reemerged for us. Now we can drill
down a little closer and that’ll show some
data from the state lab, which sorta lines up pretty
closely with this map. We probably need to
combine, data here. So this is from our
diagnostic lab at UW, here. We’ve looked at
data, I asked Brian to sort of compile,
data, Brian Hudelson, in our diagnostic lab over
the last couple of years. So before 2010, we had no
confirmations, of Goss’s Wilt. So 2010, we started
to look for it, and you see, we did find,
down here in Grant county. And you’ll notice down
here, Grant, Lafayette, year after year after year,
this is kind of where we, first start to observe
Goss’s, each year. And you’ll see in 2015,
again, we had Goss’s down here and then we had Colombia. I hear anecdotal evidence,
over the last couple of years that Marathon, Lincoln, this part of the
states had Goss’s. This is generally not a
zone where we find it. Again, a lot of this is related
to the conditions. So higher risk things,
things that we did this. Warmer temperatures, lots
of rain, and then often some damaging event that,
that like a hail event, which allows this bacterium
to actually enter. So bacteria can’t
just enter the plant cells like, Northern Corn Leaf
Blight can. It has to actually have
some wound or other natural opening to get into the plant. So the patterns we
often see, usually around where we see
wind damage, hail damage and those sorts of things. So why have we seen this rise? I borrowed this slide from Marty Childers over
at, Michigan State. I think this really
kind of sums things up in a nice bulletin list. We’ve had a sort of change
in production systems over the last few years. Corn prices were strong. So what did we do? We put a
lot of corn on corn. This is a residue born pathogen, survives in that
old corn residue. It also can survive on
weeds in the field. So poor weed management
can contribute to this, but we think a lot of the
residual inoculum is in, in some of this residual
corn residue out there. So related to that,
minimal till systems, we’ve had a switch,
which I think is a good thing for
soil management, but this also is sort
of a balance for us now, as we try manage these
residue born diseases, right? We’ve moved to a minimum till
or no-till system and that leaves a lot of residue around. So opening up the rotations
here, can help us balance that no-till system and balance
that residue that’s out there. Also, the susceptibility
in the hybrids certain genetics out here have
allowed us maybe, to, we had a good handle on it, and then maybe we
lost some of that resistance on hybrids,
selecting for other things, like Northern Corn Leaf Blight, and
so that may have driven, some of this as well. And then, we’ll also have
researchers in our pathology group also looking at
virulence of these pathogens. So they’re collecting
isolates of this bacteria and investigating that. And it’s likely that
we have some increased virulence here in the Midwest
which is contributing to that. So with that said, because
we’re dealing with a bacteria, we can’t spray a fungicide. Darren talked about that
in the previous talk. So we have to look
at other things, that we can do besides just
spraying something. And so, here’s sort of the
management plan in general. Plant the most resistant
hybrid you can find, which is appropriate
for your zone. Use some tillage
maybe, if you’re going to shorten the rotations. You know, if we’re relying on
a corn on corn type rotation, then we probably
need to do something to manage some of that residue. So maybe, switching from
no-till to maybe a minimal till. Doing something to try to
get that residue breakdown. Again, longer rotations,
obviously would be advised. I think with the price of
corn, where we’re at now, that might help our
decision making process to get ourselves out of
this corn on corn thing. And then good weed
management, is recommended. So our, our colleague, Darren
and my colleague at Purdue, they, just published a
nice fact sheet, actually, looking at other grassy
weed alternative hosts. So if you search alternative
hosts to Goss’s Wilt on Google, you’ll actually
come up with this fact sheet, and I’d encourage you to
kind of take a look at that. You know one of the ones
that are in there, Foxtail, things like that, these,
they can be alternative hosts and contribute to
the inoculum loads. And again, remember
that fungicides, are
ineffective here. We’ve also had some work
done, both in Nebraska and Indiana, looking
at baceteriacides and these sorts of
other products out there besides fungicides. And they’ve been unable
to actually find any efficacy, towards,
this bacterium. So bare that in mind,
there’s not a lot that we can do in season. We’ve got to make
some preparation in
order to manage this. To sort of switch gears here,
and talk about the other really important disease, we
have Northern Corn Leaf Blight. Again, this is this has
been a continuing issue. year in and year out, we
might have a little bit of it. Other years more. The last couple of years,
I’d say we’ve had quite a bit of Northern Corn Leaf
Blight. And that’s probably been
our major issue that we’ve taken a lot of time to control. The major risk factors for
Northern Corn Leaf Blight include a cool wet environment,
so 2015 was the banner year, really, for the
weather conditions that
really favor this. We had a nice, cool
season all the way along. and then we had heavy
dews and rains that were pretty frequent, and that
really favored not only the initial infections, but it
also helps these spores move from the lower leaves up to the
upper portions of the plant. There was also large
amounts of residue in our, our corn on corn, and,
and no-till systems, which are probably contributing. Again, we’ve got a
residue born pathogen. Maybe some susceptible
hybrids out there, again, a lack of rotation, and
races are an issue here with Northern Corn Leaf Blight. So the most prevalent
race, since about 1999, has actually been race 1. Race 0, was, is found in the
Midwest, and that was one of the more predominant
races in the 90s, and then we had a
shift to this race 1. And more recently, we, were,
there’s some evidence that suggests yet another shift. So that could be
also contributing to
some of what we’re seeing in terms of
maybe an uptick in Northern Corn Leaf Blight. Just to show you some symptoms
up close here, so this the sort of tell-tale symptom, again is that sort of
cigar shaped lesion. Again, these things don’t
get much bigger than maybe six, seven inches long, but they can coalesce if you
get enough of them on a leaf. And you can see,
there’s a couple of these lesions starting
to coalesce here. So that’s where people
start to get confused. Now one nice, thing that does
happen with Northern Corn Leaf Blight, is it is, it’s a
prolific sporulator. Especially when
we have heavy dew. If you get out
there in the morning, you’re doing some
scouting, a lot of times, you’ll see this
grey, growth on the, in the middle of these lesions, and that’s actually
the sporulation. If you had your handy
microscope out in the field and could look at this,
this is what you’d see, you’d see a lot of
little hairs here, and then these little
banana shaped spores, actually, on the
ends of these hairs. So each of these
lesions can give rise to thousands of spores. Then you can have hundreds
of lesions on a plant, containing thousands of spores. You’ve quickly got
millions and millions and millions of these
things, just moving around. And this is one reason why,
if the conditions are really conducive, you can have it
move pretty quick. You can see I’ve just, I
hear people talk about, “Well, it just blazed
through my corn in a week.” And that, that can happen
if the conditions are right, just because of the number
of spores you see here. In terms of management,
choosing a resistant hybrid, you’re gonna hear a pathologist
go to resistance first. We still think that’s a
great tool and probably the foundation of any good,
any great, management plan. You’re gonna need more than
the old Ht1 resistance, it’s not going to be
effective against race 1. You’re gonna have to look
at things with the HtN or Htm1, Htm2, et cetera. So, those things will, pick
up the resistance of some of the other races that, may be predominating,
the populations. Again, managing corn residue,
I think where the prices of corn are at, that’s going to
help us, again, try to get ourselves out of this
continuous corn rotation. Open the rotations up
here, which will help us with the residue management. I’m gonna kind of jump to the
punch line for the rest of the talk, here
right off the bat. I gave my students a little
lecture about foreshadowing in literature, and you can
kind of give the punch line away early, and then
show the data here. So really, we know
from a lot of work, which I’m going to show
you here in a minute, the best chance for
economic return, in the upper Midwest here,
is usually if a fungicide’s applied around BTR1. Again, because we’re starting
to see diseases start at that time, and then we’re
trying to preserve yield on those ear leaves, and so,
if, if there’s active disease happening, prior to tasseling
we, we would likely see some success with a
fungicide application. If there’s not really much
happening prior to that tasseling period, then the
success goes down quite a bit. So that’s a really
critical timing for us. So the goal here is,
again, is to protect those ear leaves, and that VT
timing is really the place that you want to be out
there, doing some scouting. So what about using a
fungicides on field corn? There’s a lot of debate out
there on whether we should just be recommending spraying
fungicides across corn and soybeans and just take the
yield benefits that we get. Again, like Darren alluded, I
don’t think it’s that simple. I think you really do need to
consider a few things here. We’ve got some pretty good
evidence now, this table here is actually compiled by Kiersten
Wise, however, myself, Darren and a lot of the pathologists
in the corn belt in the US, (throat clearing) we all contribute data
to this every year. And Kiersten updated
this table for us, so what you’re looking at here
is the different years where we had studies, and these are. We’re getting up into
the thousands of studies now across this six year period. So there’s a lot of
observations in here that give us these meanings. And what you’re looking at,
is just looking at timing. Regardless of the amount of
disease out there, what’s the benefit over not treating
across the corn belt at these various timings? So, if you want to just jump
here to the six year average, you can kind of see there’s
some ups and downs across here, depending on the weather,
and the response in the corn hybrids and that sort of thing. You can see, on average, about
two bushels at the earlier timings of application,
that standard timing at the V2 to R2, stage,
giving us almost five bushels. And then the double application
if went early and then came back later with a
two-pass program, actually not giving
us much added benefit, over the single-pass. And this is so, this is
one of the reasons why we’re really sort
of focusing in here. Again, on the VT, because
we see if we’re just going to spray, regardless of
the disease levels, the odds and the, and the added bushels
are probably a little higher at that stage, versus maybe
the two-pass, or the v5 to v8. I would argue in your
decision making process, the other thing that you
probably really need to consider, and I’m sure all
of you do, as good, farm managers, is you gotta
look at the pricing. And I’ve showed these
slides before, and prior to, last year, we were really
talking about things that listed, had a list price up
here around $18 to maybe $24. And I know my industry
colleagues beat me
up all the time, that my pricing’s too high,
but these are the list prices that, that we can get ahold of. Now, what’s going to change
the game, probably, here a little bit, is generic
formulations and
we do have a lot of pre-mixed formulations. Darren talked about
the combination DMI, strobular in products now. We do have some of those
that are off patent that are coming off generic
formulations for 2016. And so, now, we’re
looking at pricing, so I hear on the street. I hear that the pricing’s
going to be more $10-14. So maybe you guys can agree
that we’re down in this zone. So our current prices today
may be $3 to $4 a bushel, $4 maybe strong. What we’re looking at
here, is in order to just cover our price of fungicide, I’m not figuring the
application costs in here, now. This is just the product, we
need somewhere between two and a half and almost five
bushels to cover the costs with these generics. Now, if you look back, if we,
we went back just a second and looked at the slide, we’re right in that zone
here with our VT. So we’re just breaking
even, if we look at the six year average
across the corn belt. So before this, before
we had the generics and the lower pricing, we were
really struggling to try to get our money back on
these applications. Now, we can just
look at yield. And there’s no denying that
spraying a fungicide, generally on corn, gives us some
positive return. When we just look at
straight up yields. And we can see this,
this is a trial in 2015, up at Arlington, and what I
did here, is I just looked at the various timings, and
I’ve overlaid the number of observations we had
at those timings, here, out of that trial. Then I just looked at straight
advantage over not treating, and you can see we had in the
earlier applications here, we had maybe around
five bushels, the VT, three and a half to
four, somewhere in there, and then I’ve overlaid
the break evens here. So the yellow areas here
is where we would be with the generic formulation, so
yes, we broke even in both the early and the
standard timing. Usually, it’s pretty hard to
see things happening down here at the two-pass, we’re sort
of moving away from that. We think we really need
to just get things down to a one-pass, because it’s going
to be hard to make up twice, that bushel that I showed you
in the, break even in order to pay for the products. So really, the focus is up here. And so you can see, yeah, we
probably broke even this year. We may have made a
little money, as well, on some of those treatments. If we wanted to look
at some other data, get out of Wisconsin,
maybe look at Iowa. This is some data that Allison
Robertson shared for me, or, shared with me from Iowa. So here’s some trials here. Looking just again at timing,
and what you’re looking at is the frequency distribution
of success compared to the non-treated. So, I obviously, bars going
down, would be a loss in terms of yield, compared
to the non-treated. And then a positive
bar would be a gain. And so in the V5 timings
in Iowa, you see there’s a 50/50 chance, at least
in the 2015 data of having, some success there
at the V5 timing. When you look at R1, however, the success goes up
quite a bit. And again, this is
whywe lean toward this timing as being one
of the important ones. And again, you’ll see the
mean advantage here, over the non-treated is around
five, almost six bushels. Five and a half to six
bushels in the Iowa data. But again, you can see the,
the two-pass program, yes, it gives us a little bit higher
mean yield, but really not, I wouldn’t argue a significant
advantage and so, again, even in the Iowa data, since this
VT-R1 timing seems to again be the one that we lean towards. Now, I would argue like Darren
did in his talk, the disease levels really do matter. And I know, that that means
we’ve gotta get out and we’ve gotta do some work to make that
decision, and it’s just not as simple as saying we’re just
gonna spray all the corn and soybeans out there. I wish it were that simple, but
it’s not, and we really have to consider disease here. In 2011, there was a nice
research publication, that came out. Actually, some data from
Wisconsin when Paul Easker was here, was included in that,
and so I just want show you some, some things out of that
trial at that time, or out of that set of data at that time. It looked at some different
products and at that time, there was still some single
mode of action products being applied on corn, so
they looked at Headline, and they also looked at some
of the pre-mixed products now, which are more common,
the propiconazole plus trifloxystrobin
combination, and the propiconazole plus
azoxystrobin combination. Now, if we want to just
look at straight up yield, compared to the check here,
so we’ve got these box plots which show the mean and then
the variants around that mean. Yes, we, we definitely get some
sort of mean yield advantage over the non-treated,
when we look at these various products,
and especially with some of the pre-mixed modes
of action here. There’s no denying it, I
think any pathologist will tell you, “yes,
that does happen.” Now, what, what you really
need to consider though, is how much advantage are you
getting and is that really going to actually
cover your costs? Because a lot of times,
people get tunnel vision and they just think, well, boy
I got positive yield. And, and I must be getting
some advantage here. But you gotta
still pay yourself. You gotta pay for
the application, you gotta pay for the product. And so they took that
into consideration,
and they split out the chances of getting your
money back, based on the amount of disease that was there. Okay. So what you’re looking at,
and I’ve highlighted this group of, of tables here, and
this group of tables, because these are the
pre-mixed products. So these are the things that
you’re most likely to be spraying these days, and what
you’re looking at here, is the probability of not offsetting
your fungicide costs. So, of not having success. So in the, graphs here on
the left, a higher line would actually say there was less
success in having and recovering your fungicide costs. Versus a lower line, which
would tell you that you had higher success. And so you can see, where, if
all your disease severity was less than 5%, the odds of
actually getting your money back were pretty low, at the
various corn prices. So these lines are just
the various corn prices. Now if you look at when disease
severity was higher than 5%, so when, when in this case, it
was grey leaf spot on the ear leaves was higher than 5%, that
success goes up quite a bit. And the odds of
getting that back, now, at some of these corn prices,
are actually pretty good. If you could just hold the
question until we get to the end, because we’re,
we’re recording here. So, now let’s look at what’s
going on in Wisconsin. So I can do the same analysis.
This is called a meta-analysis. I can actually go back in time, we can extrapolate that data. We can do another, set of
analysis on the variants and means, and I can
calculate some probabilities for here in Wisconsin. So that’s what we did. I just did this a
couple of weeks ago. We went back in our data
sets the last three years, from 2013 through 2015, and then we used
observations only from the pre-mixed
fungicides products. So, only where we had DMIs
plus the strobilurins. Again, I think these are
the things most relevant to the corn industry right now. And then we looked at
timing, V6, V8, or VT. We had a total of 41 replicated
study observations within this data set, so it’s a pretty
good data set in that study. And then we looked
at distributions and
meanial advantage, and all these sorts
of tasty tidbits here. So we can line up the frequency
distribution, just like we’ve done with, in
previous studies here. And so what you’re looking
at are the yield differences relative to the non-treated
check here, out of those 41 studies where we had,
those pre-mixed products. And it’s interesting when
you just line them up, not taking into account
the disease levels now. So just straight up yields,
no disease levels in this analysis here. You can see that
the distribution of
positive return versus negative is actually
pretty equal. And actually it’s right
around 51% at positive return. Now, if you’re into statistics,
I’m into statistics, so I like to look
at these things. So, my confidence, actually,
in getting this positive return is actually fairly low,
because the statistics tell us that the probability of
chance actually comes into be a big player in this data set,
mainly because the frequency distribution is pretty equal. So basically, what it’s
saying is we have equal odds. We have a coin flip, regardless
of whether there’s disease out there or not, of getting those 2. 2 bushel
mean advantage. Not great odds. I don’t know if I want to
leave things up to a coin flip. I’m not that, that bold. Now what I can do, I can go
in and parse the data set out, and account for
the disease levels. So, I, again, this is Northern
Corn Leaf Blight, now, because that’s our
main issue here. And we used the 5%,
disease severity threshold. So very similar to what
was, what was done in the prior study. Now in the top graph here,
you’re, you’re looking at the frequency distribution
of studies. Now we’ve cut that
study, kinda down, to fewer observations here. And, ’cause we’ve
had to split out the high versus low disease. But you see, when disease
levels are less than 5%, we have very little
likelihood of actually getting positive return. In fact, the mean, if
you just want to look at the straight up mean, is
actually a negative mean. Now that’s really not
different from zero, if you want to talk statistics,
it’s not significant. However that’s not very,
positive in my mind, when we don’t have a
lot of disease around, especially Northern Corn Leaf
Blight for us here in Wisconsin. Now, we can look at it
from the other direction, if we had high levels of
Northern Corn Leaf Blight, maybe greater than
5%, now we’re talking. 74% percent of those
observations were positive, the mean yield advantage
here was 5. 4 bushels, and we had a highly
significant mean. And this is, this goes with
what was published earlier in that other data set, they were
looking at grey leaf spot, we’re looking at Northern Corn
Leaf Blight, but we’re seeing very
very similar responses. Now the other nice thing that
we can do with a data set like this, and, the calculations
that we can do, sort of in the background, with with
statistics, is that we can then come up with some probabilities
in return, similar to what they did in 2011. So I did that, I took those
means from the high disease situation, low disease
situation, I used our generic products, sort of where we’re
gonna maybe calculate some return on investment, and
then I was actually able to generate the probability
of recovering the fungicide application cost here. So you’re looking
at the probability
that we will get some return in this particular chart
for the low foliar disease pressure. So, if our corn is somewhere
between $3 and $4 a bushel, that’s what we can sell it for,
we’re looking at this green, or this light red line here,
and if we’re considering the generic products, our
range of success here. Whoa, that’s interesting. Our range of success
here is somewhere between 12% and 22%. In the low disease situation. So you’ll remember from
the frequency distribution, we did have a positive mean,
but it was only 2. 2 bushels, and that’s not enough
to pay yourself back. You’re going to lose
money, even though you’ve got a positive return. Now in the high foliar
disease pressure situation, the game completely changes. You’ll see that these lines
go up quite a bit. So if we look in the
same scenario here,
using those means, and they, and the corn costs
$3 to $4 dollars a bushel, now we’re up at 50% to
65% probability of success when we use a fungicide. Disease matters, okay. And, and the level of return
that you’re gonna get matters. Not just being a positive
return in terms of yield. So the summary here, foliar
diseases can rob yield on corn, there’s no denying that. Fungicide application in
fields where foliar disease pressure is high, equals a
high odds of recovering the fungicide costs. Sure. I will be with you every
time, go out, spray, control the disease. That’s what fungicides are for. Fungicide application in
fields where foliar disease pressure is low, there’s low
odds of getting recovery. Sure, you might be in a field
where you put a check strip in that field and you
might have 30 bushels in that hot area. You might go to the
next zone in that field, where maybe the soil type’s
not as good and you might be 30 bushels the other way. I get that question a lot. I put one strip in my field and I had 30 bushels advantage. My argument there is, go put another strip in
another part of the field and see what
advantage you’ve got. You’ve got to replicate these
things across the trials. Okay, and take that
mean advantage. And fungicide application
timing, if you had to ask me, what the critical timing
would be in Wisconsin, I agree with my colleagues
in the other states. I think the VT/R1 timing is
where success is gonna be. So you need to do some
scouting prior to that timing to make your decision. If you’ve got active
disease on the lower leaves, especially Northern Corn Leaf
Blight, get out there and
do some application. If you don’t, follow it
through the silking period, and if you still don’t
see things showing up, then you can probably, hold
off on that fungicide spray. So I just kind of rattled
through some of these recommendations here,
again, do some rotation. Residue management. You’ve gotta do some scouting. The best time to apply
would be that VT/R1 timing. (applause)

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