▶ 2026 Wisconsin Insect Pest Outlook

0:05
Well, thank you for that introduction and this opportunity to talk insects to everyone.

0:10
I’m going to be looking into my magic ball and telling you exactly what the pest problems are for the season.

0:16
I jest. Obviously we can’t do that, but what we can do is try to be as best prepared as possible.

0:23
I’m Emily Bick.

0:24
I’m the Entomology Field and Forage Extension Specialist.

0:29
And I’m going to start with a little bit of a year’s end review.

0:33
Looking back on 2025 especially because it’s really important to understand the issues that we were running into. With some of the earworm resistance, with slug concerns and true armyworm to better contextualize future seasons.

0:49
Then I’m going to do a swing towards 2026.

0:53
We truly are concerned about slugs this year, right?

0:57
We were all talking slightly earlier about how wet the year was right before everyone hopped on and we are are concerned.

1:05
So I want to give everyone as many resources as possible.

1:08
We’ll lean into talking a little bit about alfalfa weevil.

1:12
It’s been reported already in Iowa and some of our southern neighbors.

1:18
I’m in talks with some of the entomologists and similar roles there.

1:22
So it’s something that we want to be aware of.

1:25
We’ll talk about corn earworm looking forward under those resistance issues.

1:29
And then we’ll talk about a new pest that has not been formally reported in our state.

1:34
But one, I’m much, very much concerned about soybean gall midge.

1:38
And then finally, I’m going to wrap up and talk about how to stay informed.

1:42
We’ll talk about this insect pest text alert service that I launched alongside my Extension and DATCP colleagues.

1:48
We will talk about the data that that’s generated from including the DATCP trapping network, which is an extremely useful resource within our state.

1:58
And then we’ll wrap up talking about those Extension pages and some combination of those should help everyone stay on top of scouting and past problems as the season progresses.

2:10
So looking back at 2025, I was actually really happy. 2025 was not a uniformly high pest pressure year.

2:19
We did receive and and these come in in phone calls and emails to me, to my colleagues and Extension and DATCP as well as personal scouting.

2:28
We did realize that the alfalfa weevil in certain parts of the state was actually rising.

2:34
Our Extension pest team was extremely concerned about slugs based off of some reports from 2024.

2:41
However, even though we launched some slug programs to do some research as well as run a network of traps to monitor, those slug concerns did not materialize.

2:51
Primarily last year, there were some reports of potential efficacy failure for pyrorethroids with corn earworm that was reported.

3:01
And we actually went out and collected those insects, sent them, my lab sent them out to a colleague at the USDA, Brad Coates in Iowa.

3:09
And we found the resistance gene, which I’ll talk about a little bit more and how to contextualize how concerned we should or should not be.

3:18
But the main issue last year was true armyworm, which is this moth that we see over here.

3:25
It was really interesting.

3:26
True armyworm started showing up in our DATCP trapping network.

3:30
And this is a a screenshot from last April, kind of mid-april.

3:34
So actually a week before this week.

3:37
We haven’t really seen it yet in our trapping network showed up way earlier than the corn was there way earlier than any of the grassy crops that true armyworm fed on, right?

3:53
But true armyworm actually has two generations in this part of the world.

3:57
So even though we had that early migration, the risk was really low for that first generation just because the the crops weren’t up that this this pest could feed on.

4:07
But we were a little bit had our ears perked about that later generation and what it might do.

4:14
And inevitably, yes, the second generation of true armyworm kind of moved off of the weedy grassy margins of the field or the particularly grassy fields where those that first generation that migrated in from out of state, right, this past can’t overwinter.

4:31
It laid eggs in that grassy margin or in kind of weedy fields, and those ones became a major, major issue.

4:40
And what does that actually mean for us?

4:45
Well, from a management perspective, these outbreaks develop really, really quickly.

4:51
So having that tie in with that trap network gives us a little bit of an early heads up that there might be something to watch out for.

4:59
We weren’t sure if it would become a problem or not.

5:02
And it’s certainly the migration happened way too early for that first generation.

5:08
So we from a management perspective, the lesson is watch for more moth flights, but or not not just watch for more moth flights, but actually watch whether the crop is at a vulnerable stage when that next generation arrives.

5:22
And one really critical thing, I received a lot of phone calls this this past year, in 2025 about it.

5:29
The larva are no longer susceptible to insecticides as soon as they hit that about 3/4 to 1 inch size, right?

5:38
We’re looking at a at a fifth instar.

5:40
Those guys can get up to two inches long by the time you can really see them in your field if you’re not actively scouting week after week, by the time they’re just literally marching along like an army knocking those grasses down, it’s probably too late.

5:57
Which is where that early information about looking at those moth flights or looking at the the pest text alert service, right.

6:04
That’s where it really, really helps to get that early warning heads up hopefully in time where the pest is still susceptible to insecticides.

6:16
So we also launched last year this this two-part slug network.

6:24
We both had a set of of traps that were entirely volunteer based that were located in various counties across Wisconsin.

6:34
Dane Elmquist led the coordination of this trap network where we basically put these large shingles out in folks fields.

6:43
We launched this.

6:44
We basically found we did not collect many slugs last year, but it was a good practice year because this year we are concerned about slugs, especially with that wet spring.

6:58
Now slugs are majorly damaging, especially early season.

7:02
I’m now transitioning into the 2026 outlook rather than the look back at 2025.

7:08
And they’re damaging, especially if those pests can feed on kind of the growing node of the plant.

7:15
So luckily for corn and you see kind of that raggedy ripped holes in the corn on the left over here.

7:21
Luckily for corn, the growing point is actually below, below where the pest can reach it.

7:27
However, for soybeans, that growing point is above ground.

7:31
So soybeans are actually more of a of a risk or at risk to slugs.

7:39
A group of us, including Laura Flandermeyer, Dane Elmquist, and Jordan Kampa put together this little decision tree set to figure out what the risk of slug damage was to your particular field.

7:53
And Laura’s got the resource.

7:54
I think she’s sending this out in, in the in the chat right now.

8:00
We basically first want to ask what are the spring conditions like? Is it warm and dry or is it cool and wet?

8:07
I think we know we’re on the right side now. We’re in the cool and wet side.

8:11
The next question is what type of tillage do you have?

8:15
If you have conventional tillage, you’re actually at a low to medium risk of slugs.

8:21
And that’s because when you have a no till or a reduced till surface, there’s much more surface residue, which means that the soil area and the kind of just above ground area is much more moist, which is where slugs thrive.

8:38
And then we actually go to the crop and we ask, ok, are we on corn?

8:42
Ok, are we seeing seedling deformation kind of like we saw before?

8:48
Is it over 40%?

8:51
If, if it is, then maybe it’s time to assess our risk for soybeans.

8:56
We can seek guidance in that VE to V1 stage and there is a risk of stand reduction during that early stage.

9:05
If we’re seeing the corn, corn and soybean damage from slugs well after that early point, it probably is a really low risk for you.

9:16
Now, one of the things we’re trying out right now is while there are various slug baits, they’re all really expensive and there isn’t true threshold in Wisconsin for for those types of baits.

9:26
But we’re actually investigating if it is possible to use a different type of chemical.

9:31
So we’re going to be running some chemical trials based off of some stakeholder reports that something worked.

9:37
However, I don’t want to report on that until we really know if it worked or not.

9:44
So if you’re interested in SlugNet, if you’re interested in kind of counting shingles in your fields, the steps are pretty simple.

9:51
There’s a, a website associated with Extension.

9:54
You register, you explain what your fields are, we explain the monitoring protocol.

9:59
You fill out this form history or this field history form, you follow the instructions to put up the shingle traps, and then you actually go online and you report the data weekly in that online form.

10:12
And then Dane aggregates this data every single week so that we can see not which farms have more slug pressure or which ones don’t, but which counties are having those large numbers reports of slugs.

10:26
Ok, we’re changing gears a little bit here.

10:29
So for alfalfa weevil, Wisconsin reports are on the rise, right?

10:34
This is, this has been a trend across the entire Midwest, but year after year, we’re hearing more about alfalfa weevil.

10:43
Alfalfa weevil is mostly devastating towards the first cutting, but if you have really high pressures, it could affect that second cutting as well.

10:52
The threshold is if 40% of your alfalfa stems are showing larval feeding and you can see what that larval feeding looks like with the like massive, massive amount of defoliation.

11:04
And I would actually go in and and double check, use a sweep net, check multiple parts of your field.

11:10
See if you can find these tiny little alfalfa green and black headed alfalfa weevil larvae.

11:19
And you can see those larvae in in that picture from Krista Hamilton from DATCP.

11:24
And the time to start checking is at 300 degree days.

11:28
But this is also where the pest alert system comes in because we’ll be sending out an alert.

11:34
In fact, for the last two years, we’ve sent out a regionally specific alert at the time where it’s important for you to start scouting your fields for that alfalfa weevil. Jumping topics again.

11:49
I want to transition to corn earworm.

11:51
Corn earworm is really a generalist.

11:54
It eats all sorts of things.

11:56
It’s called cotton bollworm in cotton.

11:58
There’s a tomato specific name for it, which means that by the time it gets up to us, since it can’t actually overwinter in northern Wisconsin, we essentially get the resistance traits that have been selected for by our southern neighbors.

12:16
At some point, folks in my southern colleagues actually went through and genetically ID’d 2 different major populations.

12:24
One came out of Florida and one came out of Texas, and then they showed where those populations ended up. And we get the Texas population.

12:32
But as that that insect has generation after generation and migrates and moves up and moves up, especially on storm fronts, it acquires that resistance gene.

12:46
And you can actually check and see is it time to do anything and is it time to protect your corn, especially if you’re using untreated or non-GMO corn or if you’re seeing 5 to 10 male moths in a trap. And you can see that pheromone baited Hartstack trap in the field over here, and 10% of your corn is silking, then it might be time to do something.

13:09
Now one of the concerns that has been reported literally for the last decade in our very, very southern states is pyrethroid resistance.

13:19
This resistance may have evolved naturally, right as in over and over exposure to pyrethroids, but it also evolved because a pest called old world bollworm.

13:32
Instead of Helicoverpa zea, it was Helicoverpa armigera actually made it into the population.

13:39
This is literally the European equivalent in the same genus.

13:43
Came to the US.

13:44
It landed I think it was around 2014.

13:47
Don’t quote me on that one.

13:49
And it’s, it started meeting with our local Helicoverpa zea, or corn earworm, population and it handed off this gene CYP337B3.

14:01
And last year I got a report from a stakeholder that some of the fields that this particular crop consultant was monitoring had sprayed correctly with pyrethroids 3 sprays over the three weeks of silking completely adequately.

14:15
It’s protected the field and yet there seemed to be a lot of corn earworm on the crop and no one in fresh market corn especially really wants to be eating or selling corn with that worm at the very end of it.

14:31
So we actually went out and and sampled. We collected some of those insects, we collected some of the larvae, we collected some of the adults and we checked and across these three fields, 87%, this is after an efficacy failure event happened.

14:45
These were all in southern Wisconsin.

14:48
87% of those fields had that old world bollworm gene, which is a problem, but it isn’t necessarily always going to be a problem, right?

15:01
Since this pest literally it’s too cold to overwinter in Wisconsin.

15:05
We’re not even well within the transition zone of where it may or may not be able to overwinter.

15:12
Because this pest remigrates every single year.

15:16
It doesn’t mean we will always have this level of resistance.

15:20
So this year, especially in southern Wisconsin, we’re going to keep our eyes out.

15:24
We’re going to do as much moth testing as we possibly can to see if this is going to be a problem and if we need to move away from pyrethroid resistance, that that decision is going to have to happen every single year.

15:42
Ok, final piece of bad news for 2026, I shouldn’t say bad news, potential bad news.

15:50
There’s a pest soybean gall midge, that has just reached our border.

15:55
It started devastating our southwestern neighbors, specifically Nebraska, Iowa, South Dakota.

16:03
It was, it was it’s just starting to get into Kansas and it was reported in Minnesota for the first time, I believe in 2018 and has spread steadily since across the state. Last year in 2025, it was reported in Dakota County right across the river from us, which means that it may or may not, but likely will be in our fields.

16:31
This is this is a tiny midge pest that’s easily mistaken for for very similar ones.

16:37
This is a picture from Erin Hodgson’s website out of Iowa State University.

16:42
But basically the pest creeps in on the borders of soybeans and takes advantage of cracks in the stem.

16:50
So in order to scout for it, you literally need to go into the border of your soybean plant and take a knife and start cutting away at the side of your plant to see if you can find these.

17:01
These tiny, tiny larvae that are either bright orange or white, depending on what life stage they’re in.

17:09
And it’s a weird one.

17:10
It was actually a native pest.

17:12
It’s not invasive.

17:14
It kind of went over from a, from a local landscape, I guess, type of plant and moved into soybeans, right?

17:25
Nature finds a way, but it doesn’t have the ability to put the eggs or yeah, to place its eggs directly in the soybeans without this like fissure or crack in the bottom.

17:37
Usually that happens at that V2 stage.

17:41
So prior to V2, the soybean plant is not susceptible.

17:45
After V2, it is very susceptible.

17:48
And we’re really lucky.

17:49
There has been all sorts of research on biocontrol.

17:52
There’s all sorts of research on what potential strategies would work to deter soybean gall midge.

17:57
But first, we need to find it.

18:00
So I’ve invited some of my Extension colleagues from Iowa, from Kansas, from Minnesota to actually come up and help me look and help me scout.

18:08
And while DATCP has been scouting for a very long time, we’ve been unable to find it.

18:13
Hey, since it’s now across the border from us, maybe these experts can actually help us locate this pest in our state, which would then allow us to give better information to you all.

18:25
Ok, that was the bad news portion and please forgive me for being excited.

18:30
I’m a pest person so I live for the those bad news scenarios.

18:35
There are multiple ways to stay informed about the pests during the growing season.

18:42
I keep mentioning this insect pest text alert service that my lab led in combination with Extension and DATCP.

18:50
So that is one service.

18:52
DATCP also has been trapping for years and years.

18:55
We have more than 30 years of data and a whole range of pests on how they enter our system, what their population dynamics are doing.

19:03
We’ve even have maps of all these pests.

19:06
And then the Crops and Soils page at the Division of Extension has a, a pest management website which actually keeps up to date with the latest news, right.

19:16
So it’ll, it’ll talk about how to manage alfalfa and it’ll talk about kind of what our slug populations are doing.

19:25
So all three of these these these mechanisms are in place to try to give you all really, really timely information about pests.

19:37
When I’m talking about the pest alert service, basically you can log on to the Division of Extension website, click a link to register.

19:47
All we need is a name, a phone number and e-mail, and then we ask you your region.

19:51
The email’s really important in case the text fails.

19:54
And it’s good for me to be able to not call your number because it didn’t seem to be able to receive a text message, but shoot you an e-mail to see what happens.

20:03
And then up to once a week the last two years, we’ve sent out I think 5 and 6 alerts for year one and year 2, we will send you a timely regionally specific text alert based off of that DATCP finding.

20:19
And I should also say also based off of our personal scouting and based off of your conversations with Extension about if you’re having a really specific past issue, that text will not just be a “it’s time to go do something”.

20:35
It will really be a heads up.

20:37
“It’s time to look for your pest.”

20:38
“This is the pest to look for.”

20:40
It will, it might include a photo, but it will always include a link.

20:45
And that link will go to a news article about just a really, really short form, what the pest is, what it does to your crop, how to scout for it, what the thresholds are, and what you can do about it in terms of chemical, biological, or cultural interventions.

21:02
And then that particular link will circle back and actually link out to your full pest profile.

21:08
It’ll link to the DATCP Field Notes newsletter and it’ll link to any sort of real time insect presence dashboards that DATCP puts together.

21:19
This is one of the the links.

21:20
In fact, this is the core of the information that feeds into that that those text alerts is the DATCP, Department of Ag, Trade, and Consumer Protection crop pest trapping network.

21:31
It is an incredible resource that we’re really lucky to have in Wisconsin.

21:34
Some of these pests have thresholds.

21:36
Some of these, like true armyworm don’t necessarily have thresholds, but it’s good for us to have that early warning heads up.

21:45
And then this is kind of the kind of information that the Division of Extension, the Crops and Soils page puts out.

21:51
It will literally be a long form on, you know, either the news or managing slugs in your field, how to identify them, all of that information.

22:01
And we’ve spent a a considerable amount of time, mostly Laura Flandermeyer, Dane Elmquist, Jordan Kampa and myself putting these resources together.

22:10
So we’re hoping that you’ll use them.

22:12
And if you don’t like using them, let us know why.

22:15
So major thank you to the entire Extension Pest management team, Dane, Laura, Jordan Kampa, Jordyn Sattler and Josh Kamps.

22:23
Thank you to the Bick Lab folks who helped put the stuff together.

22:25
This is Fletcher Robbins and Carmen Meyers, to DATCP to Krista Hamilton and Tracy Schilder and also major

22:33
major thank you to the volunteers in the trapping network.

22:36
That’s with the DATCP trapping network as well as SlugNet.

22:41
Are there any questions?