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.