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Join the University of Minnesota Extension Crops team in addressing all your crop-related questions this growing season, from soil fertility, agronomics, pest management and more. We will tackle issues as they arise to help you make better crop management decisions this season.
Transcripts are auto-transcribed. If you need more accurate transcripts of an episode for ADA purposes, please contact Anthony Hanson - hans4022@umn.edu.
I'm Ryan Miller, Crops
Extension Educator
earlier this morning.
We recorded in an episode of
the Strategic Farming
Field Notes program.
Strategic Farming Field Notes is
a weekly program addressing
current crop production topics.
A live webinar is hosted at
08:00 A.M. on Wednesdays,
throughout the cropping season.
During the live webinar,
participants can
join in the discussion and
get questions answered.
An audio recording of
the live program is
released following the webinar
via podcast platforms.
Thanks and remember to tune
in weekly for discussion
on current cropping and
crop management topics.
Good morning
everyone, and welcome
Today's session of strategic
farming field notes.
Today we're going to be
covering quite a bit
about what's going on in
the insect world here.
We know we've had a few
developments going on
both Southern Minnesota dealing
with a lot of army worms,
but then also
Northwestern Minnesota.
We're looking at a
new small grains
and insect at least
to the area up there.
To start off, we'll
talk to Dr. Ian MacRae.
He's based out of Crookston,
an Entomologist up there.
And then also we
have Bruce Potter,
IPM specialist based
out of Lambert,
Southwestern Minnesota. On two.
I want to remind folks
that these sessions are
brought by University of
Minnesota Extension with
very generous support from
Minnesota Farm families through
the Minnesota Corn
Research Council
and the Minnesota Soybean
Research Motion Council.
Again, we're glad you
could join us today
for today's update here.
My name is Anthony Hanson.
I'm a regional
extension educator
in integrated pest
management based out Morris.
I think with that I will
hand it off to Dr. Ian
MacRae in just a second here.
I do want to say that one
of the programs that we
have an extension is
what we call our Western
IPM Scout Program.
This is funded both by the
Minnesota Wheat Growers
and Minnesota Soybean Growers.
And it was about
two weeks ago that
both our scouts started
finding insect in
northwestern Minnesota,
specifically Norman Oman and
a little bit in Red Lake County.
And this was cereal leaf beetle.
And we found out
partly through an,
that it was the first find
in northwestern Minnesota.
You want to talk a
little bit about what's
the big deal with
cereal leaf beetle here
and why that was
both an exciting find
but also a worrisome
find for the area.
Sure. Thanks Anthony.
Well, certain leaf beetle is,
can potentially
cause economic loss.
And what it's in
basically all the states
that surround us,
in my time up here, we had
not seen it in small grains.
The MDA doesn't have a report of
it being collected up
here in small grains.
I spoke to one of
the local a couple
of the local scouts they
had don't recall seeing it.
Bruce Potter who was up
here actually, Bruce.
You were up here before? I was.
You were up here in the '90s?
I guess older than you are.
Yeah.
But only by a few
months. But Bruce
seems to remember seeing it,
so it might not necessarily be
the first time that
it's been hit.
And it wouldn't be unusual to
have an insect come in and
disappear if the
environmental conditions
weren't right and have a
reinvasion when they were.
What we do know about
this particular insect
is that it's boy,
what a charmer to work with.
The adults are
quite distinctive.
They're about a quarter
of an inch long,
but they have very,
very dark metallic
blue wing covers.
The posterior portion of
the insect is covered
by this really bright,
dark blue and it's
very metallic.
And then they're thorax,
so the legs are
attached to their head
are a very vibrant orange.
They're not hard to miss.
The adults really
aren't hard to miss,
but they're not around
for a long time.
They overwinter as adults,
so the adults will
emerge in the spring.
They're usually very similar
to a lot of other beetles.
Overwinter leaf
cover and duff in
the hedgerows and shoulder
belts move into a field,
they make legs, they
don't feed a lot.
In the spring, a little bit
the eggs will hatch and
you have these larvae.
Now, these are just charming
little creatures because
they're a light yellow color
and against the green
of a cereal grain,
they would really
stand out, cover
themselves with mucus
in their own feces.
And now they're this really
dark brown black blob
that actually it resembles
a little bit like a slug,
but it also looks like
bird droppings when
they're very small.
And it's probably a method
of avoiding predation.
Do you know of any other
insects that we deal with?
At least the field crop side
of things that do that?
Because, yeah, that's not
something I should say.
It's, Thank God there's other
leaf beetles that do that.
Thought Lily as well.
I know a needles will
do the same thing.
They also seem to
have many of them
seem to have this bright
yellow color as well.
Yeah. The adults and
the immatures will
feed in the same way,
and that they start on
the top of the leaf,
they're usually on
the top of the leaf.
They start feeding down
through the leaf material,
and they stop when
they get to the bottom
of the bottom leaf cuticle,
which leaves this empty area,
and it looks like
window painting.
The adults feed in rows.
They're fairly mobile
and so they're
feeding as they're
walking up the leaf
and you have these
basically windowpane look
like tracks as they go
up these very narrow,
long tracks, the
larvae which are
not as mobile as the adults.
They do have lakes,
but they're not as
mobile and they have
a tendency to feed more in
a patch across the leaf.
That actually turns out
to be a lot more damaging
simply because when they take
right down to the cuticle,
that cuticle is
going to eventually
dry and the rest of the leaf,
even if it's fed upon or not,
will drop off and
you lose a lot of
photosynthetic material there
when the grain gets into.
And I should specify, these
are only on grassy crops,
small grains, grassy weeds,
things like that is
where you'll find them
when they they're feeding.
And moving around, you
have a tendency to see
them move over to the
flag leaf when the flag
start developing and then
they're very evident.
It's not hard to find them.
Really, the thresholds
are reasonably low,
which makes because they
can cause a lot of damage.
When the plants are small,
maybe a little six plants,
the threshold is three eggs
or three larva per plant.
When they get a
little bit older,
boot, the flag starts coming up.
It's one larva, a flag leaf.
And a lot of that has to do with
how devastating they
can be to a flag leaf.
We know this thing. I've talked
to Dr. Joo over in North Dakota,
she's dealt with this an
awful lot more than I have.
I gave her a call and took
a short serial leave,
beat one on one course from her.
She's been dealing with this for
several years now and she
seems to think that
they're moving,
or moving east rather
out of Montana,
and that seems to be how
they're moving
across North Dakota.
She said they find it most
years in a number of
different counties,
but usually it's not at
economic populations.
And she said occasionally you'll
get a very similar to
what we're seeing here.
Occasionally you'll get a field
that has a heavy population,
but most of the ones
that we've run into
here's you'll find the damage,
but it's oftentimes
hard to find a large,
and there's a lot of natural
mortality with this insect.
There's parasites and
peristoids and predators,
and so I think we may not
be seeing a huge outrage.
I can tell you where we are
and are not finding it.
We're finding populations in
Noman and in Norman.
We've recovered in both.
The one field that we
first found and it was one
of the ones at the IPM
found was actually
heavily populated and at
one point it probably was at
a point where it
was a threshold,
but the vast majority of
threshold of fields
have not been.
In fact, that was
the only one that I
saw that was even close.
And I'm remembering the
numbers a little bit too.
And I think one of the first
fields we sent you to,
at least the scout found
about 25% of the
plants were infested.
And I think that's when you said
that was a threshold
in the past?
It was a little
bit too late Based
on yeah, based on the feeding.
I would say there used to be
an awful lot more lava in
there than what we saw.
The distribution was very
even across the field.
I mean, I was we were
walking transect the field,
you know, even strung out.
We had about five
people in the field and
you could find damage
all the way out
into the field and you
could find Larval.
So, we had weather field too,
Red County, that one had about
33% But that's a
research trial plot?
Actually, we didn't remember.
So, yeah, we did
we did scout down
Highway Nine and were coming
back from one of
the other things we
were doing out there.
And we did not find it on any of
the wheat fields on nine,
we did find it up to I think,
about 15 to 20 mi
away from that one.
Very heavy one? Yeah. Yes.
So if one, those are counties,
at least for a lot of folks
in Southern Minnesota,
that's far
Northwestern for them.
Is this an insect that folks
should be keeping an islet
for across the
rest of the state?
I know Southeastern
Minnesota roughly.
It actually had been
documented back and
Mda did a survey from
2010 historically been
found down there.
But from our conversation,
it sounds like it
hasn't really been
economic threshold for people
notice it too often down there.
Yeah. And that's
what I'm starting
to think, given
the distribution,
this is not something that's
probably just come into
this area in one year.
But I'm guessing at
this point because we
don't know what the
full distribution is,
we don't know how long
they've been there. But
The populations are so low in
some fields that it's
entirely possible.
This is just
something that's been
here for a while,
we've just missed.
There was one field we were in
that we really had to
look hard and we did
find a little bit of
damage and we found
one larvae and that was
after being in that field,
forths possible they could
be there at very
low populations,
and we know they're close.
They're in Walsh
County, which is
the county that's on the border
right above Grand Forks.
And we do know that
they're relatively
proximal in Minnesota.
If you're that close, the river
does not make much of a barrier
for an insect that'll fly.
Have some links in the chat
and if folks do want to
look up a article that
just came out last week,
Minnesota Crop News, this
type in cereal leaf beetle.
And you should see the
article there too,
that'll have more information
on what we look at for
scouting thresholds,
But what are the options we
have for insecticides for
this insect and how
well does it work
considering you have that
mucus layer on that?
Is that affecting Fc
at all or the insecticides
working pretty well?
Well, most of the
insecticides that I
saw you got fairly good.
When I went onto
the arti trials,
most of the pyrethroids seem
to be working fairly well.
There wasn't a lot of resistance
being recorded with this insect.
And the other one is if
there are certain amines
that are also available.
But I think that
might be overkill
if the pyrosis are working,
you know, that's
the low price point
and they seem to work well.
So that would probably
be the first thing to
go to. All right.
I think we will move over to
Bruce and some of the other
insect issues we have,
but we'll definitely come
back to you for Northwest
Minnesota because I think we'll
talk about some
dry season insects
and what's also happening
with that, because again,
showing up some parts
of the state likely to
show up in more counties
this coming week here
unless we get some rain,
there definitely are
some insects or keep
an eye out for first.
We've had a lot of calls about
true armyworm the
last week or two,
At least some of these
are ones where
they're wrapping up.
There may not be as much
they can do about it,
but what have you seen
for true armyworm?
Caterpillars are
getting calls in
that both for concerns about
what's in our field crops
but then also what's
happening in pastures too.
Because there's been
apparently a few calls
coming in Southeastern
Minnesota,
especially where
folks fed close to
maybe 50 larvae per square
foot in some well, I mean,
we've been worried
about army worms
and black cutworms all spring,
we run some pheromone traps and
light traps for both
of those insects.
And in the Southern
part of the state,
when we had those heavy
rains come through,
that those were systems that
brought migrating insects
in from the south.
I haven't I think I was on one
of these previous webcasts,
but, you know, I cut
my personal record for
army worms in a single night
and a light trap that was 195.
And then quite a few of
the following nights,
some pretty big flights have
come in on both species.
We've had injury to
a lot of injury to
pastures and grass,
hay land, that sort of thing,
But also in corn,
particularly where corn
was planted into rye.
And I think we've had
people alerted to that.
They should have been
out scouting both of
those areas because
of the high flights.
I think the thing to realize
here is that we've got,
we've had a perfect storm,
especially in Southeast
Minnesota where it's dryer.
We had weather systems that
brought a lot of mass in.
They were looking
for dense grasses to
lay eggs on in case
of army worms,
whether that be a ry cover crop
or some sort of perennial grass.
Then we had a dry
conditions set up
and that slowed crop growth.
Those larvae ran out of food
quicker and they were
encouraged to move faster.
And that's where they
get the term armyworm.
When they run out of food,
those larva move in mass.
That's what we're
dealing with right now.
There's been multiple
flights and we've
got quite a range of
arable sizes out there.
And we're going to have some
issues here for a while.
And it's not just
Southeast Minnesota.
I know they've had
some bigger flights
up into Northwest Minnesota,
so we're going to
have to keep an eye
out for at least
the next few weeks.
Yeah. That was actually one
of the questions I had was
how long we really need
to be keep an eye out
for if people are seeing
an issue right now.
When and where should
they be treating?
If we're talking about
field crops, corn,
how long is that susceptible
for if they have grass
edges. But then also
Pastures?
When is it economical
to treat pastures,
especially in these
stroke conditions?
Is that something where if
you see high numbers in
your pastures and you're
already on age out there,
is that something
you need to be out
there ahead of treating
pretty heavily or is it
a little bit difficult,
especially if some of these
larvae are more
mature out there?
Well, I think really if
the guys are wanting
their hay crap,
they want to protect it
from the insects taking it.
The threshold is the same for
grasslands and hay ground
as it is for small grains,
four or five larva
per square foot.
I think the other
thing that happens
is movement out of those
areas, kind of similar.
I think maybe I'll talk
about grasshoppers later on,
but you don't want
the larvae to move out
of those areas into,
into your field crops,
either, particularly corn.
And so I think,
you know, treatment should have
happened in some of
those fields earlier.
Some people didn't
find the problem in
their hay ground until they
were out there mowing.
But I think I think definitely
treating the treating where
these larvae are starting
from is a good idea,
or at least a border on
those areas before they
get into the crops. Row crops.
I think you mentioned
black cutworm earlier too,
what you've been seeing
happening with that?
Well, we've had some
pretty significant issues.
Some of the Southern Minnesota
beet growers have had quite a
few have had quite a struggle
with cutworms this year.
Some of that's the
same situation.
A lot of guys are planting
an ot cover crop to prevent
erosion that's a little bit
attractive to the mass.
Then when they kill that oats,
they'll move to the sugar beets.
And small sugar beets don't
stand up to cutworms very well.
It's multiple species of
cutworms in the beats.
Actually we've had some
variegated cutworm issues
or some of those
in L Flp as well.
Again, another migrant
and I just got
a picture last night of
yellow striped army
worms and sugar beets.
It's definitely a year for
migrating moth insects.
I think something we're going
to have to keep an eye on,
particularly with
this drier weather.
Some of the diseases
aren't going
to help control the
insects as well.
I've had a few other
questions come
in and is reminder to folks too.
You can use the Q and A if
you have any questions,
if you're on the, um,
chat itself here,
but swiping glitch,
are there any
updates on that one
Or is it too early to be able to
tell what the situation is
looking like this year,
where fines might be showing up,
or severity was down at
our research site in Rock
County yesterday afternoon.
And we've been monitoring
emergency cages,
and I think the populations
were are fairly low
again this year.
And we didn't haven't picked up
any in the emergency cages,
but we do have some
plants being infested.
Now, there's a few
orange larvae,
so they've been there
maybe a week or more,
but most of them are
still fairly small.
First, in stars, that infestation
is going on right now.
Okay.
I think people are going
to be asking about safe.
We'll try to have
another session
on that coming up here soon.
But yeah, it sounds like slaved,
that one has been showing up.
Some people are
finding in fields
but obviously not
threshold levels yet.
A little too early
for that one there.
But the main
question I'm getting
here is on grasshoppers.
Both Bruce and II can hand that
one off to both of you here
depending on what you're seeing.
But I know I'm seeing plenty of
small grasshoppers and some
of the hay fields out here.
Not anything too concerning
yet in West central Minnesota,
but high enough populations.
Now, I definitely want
to keep an eye on it.
Is that the situation?
You both are seeing
your neck of the woods
or are you actually
getting pretty high
numbers out there?
I'm seeing really
high numbers in
alfalfa, red legged
grasshoppers.
And it makes sense. At
least in this area.
We've had two years of drought,
dry weather, actually
severe drought.
So I think that's something
people should watch.
And again, it, it's a case
where if you're seeing
those nymphs in these
production areas that
hay or grasslands next to
it keep an eye on
that because they probably
won't stay there.
Yeah, I concur. I don't
think our populations
are as high as Bruce is
seeing down in the Southwest,
but we are starting to see
stuff in the Northwest.
Like he says, we're
starting to see nymphs.
I've had calls already,
which is early in the season.
I think we've probably had
a little bit more rain
in the fall and maybe a
little bit more early spring.
Our populations might not
necessarily be as high.
Certainly the recipe for
grasshopper populations,
any years or dry fall
followed by a dry spring is
going to give you grasshoppers.
Um, like I said,
we're probably not
as high as Bruce,
but yeah, that's
something people
should be watching
and scouting for.
Hitting the edges of the fields
and seeing what their
populations are,
like something that should
be on their radar screen.
Yeah, that's a good
reminder for folks.
I think we've hit on it a few
times over the years here.
But grasshoppers are
a dry season pests.
Partly just because
when it's wet,
you have more mortality due
to fungi that might go
after grasshoppers.
Bruce, you want to talk a little
bit more about those conditions.
You know, when they do well
versus why they don't do well.
Then the worst thing,
and I want to a comment here,
it's not every field in
every area that's
got grasshoppers.
It depends a lot on
the previous year's weather and
particularly last fall
and this early spring.
But the worst thing for
grasshopper nymphs,
and I think correct
me if I'm wrong,
is when those nymphs
are hatching.
If you have a cool, wet period,
there's two things that happen.
One is disease. One,
it's too cold from,
to move and they
starve to death.
We haven't had that this spring.
Species I'm seeing right
now are species that tend
to hatch later like
the red leg stripes.
And I'm not seeing
much of all at all.
Yeah, I think our populations
are a little heavier for
two stripes up here than
down there. They're a
little bit more common.
And that could be also because
the red lakes have a
tendency to prefer
that warmer drier climates
than the two K two stripes.
But we used to get a lot of
red lakes down in high
plains in Colorado,
so that's why I
was thinking that.
But yeah, Bruce is
100% right there.
The wrong conditions
for grasshopper at
the early season
and when they're
hatching out is a great
condition for us.
You know, they're very,
that's by far the most,
it's by far the most sensitive
stage in their lives.
They don't know when
they're emerging.
If they don't find
food within a meter,
they're probably
not going through.
So and that's one of the
reasons why those, you know,
those hot dry springs
are if it's followed
a hot dry fall,
you can start to see hoppers.
But if you've got that cool
period and it's moist,
the fungal diseases
are going to take off.
As Bruce said, that's going
to have a lot of
mortality on the young.
And as he said, moving is
critical. They've got to feed.
There's not a lot of resources,
food resources,
nutritive resources,
and a grasshopper egg.
And so they need to take
on calories pretty quick.
And if they can't move or if
it's bare ground or something,
they can't get to food, it's
going to be pretty
tough for them.
So we've been talking
about forages a bit here,
especially on the
army worm side.
And that applies
to grasshoppers,
we're finding a lot of it.
How about soybeans though?
When is that a more
acceptable crop?
Are we looking at that
later in the season
or do we have enough
defoliation now?
We'd be worried
about our soybeans.
For grasshoppers?
For grasshoppers, yes.
Well, I think is
more two stripes up there
in Northwest Minnesota.
Northern part of the
state down here.
Those are replaced
by differential.
They are larger grasshoppers.
The differentials hatch later,
but differentials and red
legged particularly will
lay eggs and soybeans,
especially if they like
firm ground, bare ground.
So no tail type situations are
preferred that
alfalfa is perfect
for them because there's a lot
of bare ground in
amongst the plants.
Um, and I think the other
thing to worry about,
not so much on grass
hay but on alfalfa,
is blister beetle larvae
feed on the eggs and if
you've got high populations of
grasshoppers in those
alfalfa fields laying eggs,
you have a tendency to
pull in blister beetles.
And then now you've
got an issue for
hay quality, particularly
with horses.
Actually, we've
gotten some calls
on those blister beetles up.
We've talked about that on
our crops calls before.
And yeah, I've had some
fields who I've seen
the great blister
beetles showing up
in alfalfa on the edges
in central Minnesota.
And if you have the beef cattle,
they're a little more
tolerant to that.
But yeah, like you said, horses,
that's more of a concern there.
The take home was
with blister beetles.
And this can be our wrap up
question here for folks.
That's one where we're saying
that if you're going to mow,
give it some time for
those beetles to disperse.
Don't be crimping it or spray
insecticide because that's
a case where you just
have the beetles
left in the hay and
then you're going to
have that irritant from
the beetles that's
going to get into
the livestock a lot easier
because you're just going
to have more beetles
out there or Bruce,
do you have any
other thoughts on
those blister beetles and
what they're up
to in the fields?
Just be aware of Yeah,
I can catch people off
guard a little bit.
I think given by the calls
we're getting in here,
don't let that Alp alpha Bloom
because that'll congregate
them in the field as well.
All right. Well, I think
that we're about time
to wrap up here.
Again, thanks everyone for
attending today's
Field notes program.
We want to, again,
thank our sponsors,
the Minnesota Soybean Research
and Promotion Council
and the Minnesota Corn
Research Promotion Council.
Thanks to Bruce Potter, Dr.
I Mcrae, for joining
us this morning.
And have a great
rest of the day,
everyone, and we'll
see you next week.