- Our next speaker that's coming up
is P.J. Leisch.
P.J. is
our Extension entomologist now.
He took Phil Pellitteri's place,
so he's the new, younger, better-looking version of Phil.
(laughter)
I guess he's faster too, he says, but I don't think
we've had a foot race done yet.
P.J. is in charge.
His role is with the insect diagnostic lab
here at Madison, so he's the person
that if you have a question with regard to identification
or a management recommendation on insects,
he's your go-to guy.
He works with his colleagues, of course,
at the university.
He works with agricultural producers in Wisconsin.
He works with a lot of our industry people
to help us with any of the potential questions
that we might have around insects.
And, of course, he gets into, also,
commercial buildings and things like that,
so he's very broad-based and diverse.
So he would help with insects in a medical facility
or in a warehouse environment.
P.J. works in the outreach area,
so one of the jobs that he has is
he teaches courses to the farm industry short course.
He grew up in Franksville, Wisconsin.
For those of you who don't know where Franksville is,
it's in the far southeast corner,
down in Racine County.
And he holds a bachelors and a masters
from the UW-Madison.
He has been in charge of the diagnostic lab since 2014.
Please welcome P.J. Liesch.
(applause)
- All right. Well good morning, everyone.
It is pleasure to be here.
As Scott said he was going over more
of the mechanical side of things,
whereas I'm talking about the buggy side of things.
Although it's really great that I'm going after Scott,
because he introduced a lot of important things
that I'm going to go over again,
things like simply making sure your bin is clean
before you put new grain in there,
proper aeration, temperature control, things like that.
If you do all those things, that can really prevent
a lot of the insect issues, and overall,
we have it pretty good in Wisconsin,
because we have these colder parts of the year
called winter.
If you go down south or to tropical regions,
where they're growing rice,
that's a nightmare situation down there.
So what I want to do today, review some of the
main groups of stored product,
stored grain insects that we see,
and I also want to talk about management.
Now when it comes to the three groups of the insects
that we see, and I'll go into some more of the details,
we've got internal feeders, external feeders that are
feeding on fines and damaged grains and things like that,
and then you've got a groups we call the fungal feeders,
that aren't feeding on the grain themselves,
but if you have musty grain due to moisture control issues,
you get some mold, mildew growing,
they're coming in and feeding on that,
but they can still be a contamination issue.
Now when it comes to the insects we see in stored grains,
about 90% of them are beetles, and to be honest,
they're a little tricky to identify
because they're all, most of them,
about an eighth of an inch long and kind of reddish-brown.
So with a naked eye, really hard to tell what they are.
But if you've got a microscope or good hand lens,
that can help with some resources.
For having resources, that can help identify them,
or if you find something in your grain
when you're monitoring, get it to a crop consultant
that knows their bugs or get it to a extension office,
extension agent, or get it to me at the diagnostic lab.
We can get it figured out, because that can have
some important implications.
If you have a fungal feeder insect in your grain
versus a secondary feeder, we might be needing
to do different things.
If it's a fungal feeder, we might need to aerate some more,
get that moisture level to drop, and that's going to be
a bigger impact on those insects.
So getting things identified is
a really important step.
Now, overall, the insects that we see in Wisconsin,
they tend to be the secondary feeders
or the fungal feeder groups.
We don't really see the primary feeders.
And then, in terms of management of these pests in grain,
really there are a lot of things we can do
without having to rely on insecticides and fumigants,
and things like that.
There are a lot of cultural and mechanical things
that we can do.
Just general sanitation,
aeration, temperature, moisture control,
which Scott mentioned, and we'll talk about
in some more details,
and then there are some impacts on location on a farm.
If you were putting in a new grain storage bin,
you probably don't want to put it right next to an area
where animals are feeding, because if we've got cattle
feeding, and there's spilled grain around,
that's a potential location where those insects
could be living and that could be a reservoir
that could get into the grain bin if it's close by.
So there's a lot of factors that can impact
stored grain insects.
Just a very general review of
stored grain insect biology,
they're cosmopolitan in distribution.
What this means is they're found practically
everywhere on the planet.
If we went back in a time machine 500 years ago,
that wouldn't be the case,
but with modern commodity trades
and moving things around, these things
have gotten moved around the globe.
There are some species, like Copper Beetle
that aren't here yet and can be a nasty pest,
but a lot of these pests can be found worldwide.
And under the right conditions, if it's warm enough,
they can reproduce and go through a generation
pretty quickly, four to six weeks.
So, in Wisconsin, that boils down to about
two to three generations per year, potentially,
during the warmer portions of the year.
Now insects, being cold-blooded,
they're temperature-dependent, and so if it get down
to about 50 degree, that is the critical threshold
for development.
You get down to 50 degrees or colder,
their metabolism grinds to a halt,
and they are no longer feeding,
causing damage for the most part,
and so the cooler we can keep grain,
the fewer problems we're going to have.
So in Wisconsin, two to three generations per year,
whereas if you go down to the southern states,
or you go down to tropical, sub-tropical areas,
they can get 10, 12 generations a year,
and so they have it a lot worse off than we do.
And why are they so problematic.
Well, if you think about a grain bin,
it's really this artificial ecosystem.
We've got this metal bin,
we're putting grain in it,
in theory, there shouldn't be any insects in there.
But if they do get in,
they're natural predators aren't there,
so we've got, essentially, an unlimited food source
for these insects, there's no wolves to take care
of the sheep, so to speak.
I mentioned earlier, they're small.
Most of these insects are an eighth of an inch long,
so they can be physically hard to detect.
Luckily we have some probe traps and things like that
to keep an eye out for them.
They can tolerate a wide range of environmental conditions.
And they can also be fairly long-lived.
If you clean out a bin, and maybe there's just some fines
in cracks, and you let it sit for half a year.
Well, there's still a chance there could be
some stragglers around.
So they can survive in some unusual conditions
for long periods of time.
And they're problematic because,
even if it's something like a fungal feeder
that might not be directly damaging the grain,
it's a contamination issue, and so you go to sell it,
the price could be affected,
or you might not be able to sell it at all
if there are so many insects present.
So I mentioned the three types of
stored grain insects.
Primary feeders, there are creatures
that feed on whole, intact grain,
so they could chew their way into a whole,
perfect, intact grain of corn, for example,
and they basically leave a hallowed-out shell
when they're done feeding.
Then we've got the secondary feeders.
These can walk up and start munching on a grain of corn.
They need something that is damaged.
They can't chew that outer layer.
So if we've got grain that has been damaged
by primary feeders, damaged by physical jostling around,
being crushed, or we've got fines around,
they can feed on those type of materials,
but they're not going to be munching
on whole, intact grain.
And then we've got these fungal feeders,
which I said they don't attack the grain,
but if we have moisture issues, and we've got mold growing,
they're going to show up and feed on that,
but they can be a contaminate in the system.
So to quickly show you a few of these primary pests,
and we really don't see many of these in Wisconsin.
Worldwide, there are six to eight major ones,
and then we see a few in Wisconsin, two to three.
There are a number of Weevils,
like Granary, Rice, and Maize weevils.
There is also a critter called the lesser grain borer,
and overall, these are not common.
If you go to warmer portions of the planet,
down south or in the tropics,
some of these insects, in some cases,
will actually infest grain when it's still standing
in the field,
and so, if you take that grain and you think it's good,
and you put it into storage, the insects are already there,
so that's kind of a nightmare situation.
And just to show you what these look like,
again, most these beetles are about
an eighth of an inch long, reddish-brown,
so they are kind of hard to tell apart.
Weevils are one that you can tell apart
fairly easily if you have small hand lens on you.
If weevils were one of the Muppets' characters,
they would be Gonzo, because they're got
a very, very long nose that comes off the front
of their head.
And there's a few species that can pop up from time to time.
We've got granary, ricew eevils; there is maize weevil.
To tell the exact species apart, you need to get them
under the microscope and actually dissect out
some of the reproductive organs,
so it's almost like a miniature-scaled game
of Operations, but you need really, really steady hands
to do that.
And then we've got Lesser Grain Borer.
This can be a serious pest of wheat,
will also get into rice.
Every once in a while, it might get into corn,
but it doesn't really seem to like corn a whole lot.
But the weevils ad lesser grain borers,
if you see primary pests in Wisconsin,
it's probably one of these.
In my two years in the diagnostic lab,
I think I've seen only one or two cases
of these, so they're not common in the state,
compared to our secondary pests and the fungal feeders.
So these secondary pests, we sometimes
call them bran bugs, because
they like to get into food products, as well.
Basically, any type of processed grains
or damaged or broken grains or fines,
they can feed on, and we've got a couple dozen
species in the state, 30 or so species that pop up
and they can be fairly common.
So, just some common examples.
Red flower beetle, there is a reason why
we had flour sifters, historically,
because you would get creatures like this
getting into the flour,
or we can see in that upper-righthand picture,
that is some of the beetles in comparison
to some Cheerios, so they are not big insects to deal with.
You do need to get them under the microscope
to tell them apart.
But red flower beetles can be very common.
Some other very common ones,
probably some of the most common secondary feeders
I see in the state, sawtoothed and merchant grain beetles.
Very closely-related beetles species.
Almost identical in that picture on the left.
We see that just behind the head,
we see this jagged saw-like appearance,
that gives them the name of sawtoothed grain beetle.
If you look like the head itself,
that picture, the upper-right, there's some
subtle differences behind the eyes,
so that's how I tell them apart under the microscope.
The reason I want to mention that,
there is an important biological distinction
between the two species,
which is that sawtoothed grain beetle can't fly.
It has to walk wherever it's going,
and so if you've got a well-sealed bin,
for a sawtoothed grain beetle to get in,
if the only way to get in is somewhere up at the top
or through a ventilation fan, if that's covered,
they're going to have a hard time getting in.
Whereas merchant grain beetle can fly.
So they can move greater distances faster,
maybe more likely to get in in the long run,
and we can see in that bottom-right picture,
compared to a penny, these things are just darned small.
Mealworms do pop up from time to time,
and we really don't see the adults as much
as the larva, which is on the left.
So that's the juvenile insect.
These are the mealworms that you can sometimes
find at pet stores to feed to lizards
and amphibians and reptiles and things like that.
So kind of a hard, crunchy worm-like creature.
And they are one of the secondary feeders as well.
Probably our most common one that we see,
Indian Meal moth.
If you peak in your grain bin and you see
little grayish moths flying around up above,
it's a good chance it's Indian meal moth.
There's two, three, four, other possibilities,
but Indian meal moth is our most common one.
Now the thing about the adults,
they're not really causing any damage to the grain.
Their goal in life is to find a mate,
to reproduce, lay eggs, and that's about it.
Whereas the caterpillars that are down,
living in the grain.
They're the problematic life stage.
For the adults, we do have some pheromone traps,
we can monitor for them,
but this one can be a fairly big problem
in Wisconsin, other portions of the midwest,
because of their behavior.
So these caterpillars are feeding and they're often
at the top of the grain,
and they produce some silk webbing,
and that webbing ties together particles of grain
or whatever's in the bin.
That's going to create some crusting,
which is going to disrupt airflow,
and as Scott had mentioned,
you get disrupted airflow, that's going to cause
moisture issues, condensation.
We're going to mold and mildew popping up
in situations like that.
One of the easy ways to tell if you've got them,
if you're lowering your grain in the bin,
like that picture on the right,
and you see those clumps of grain stuck
to the side of the bin,
almost certainly, that is Indian meal moth.
They have taken their silk strands,
made kind of a clump of grain or corn,
and it's stuck there.
So that's a pretty strong indicator.
I do also want to mention, there are
some known cases of resistance to Malathion.
Now if you're using Malathion and it seems to work
for you in your situation, great.
Keep that in mind.
But if you're using it, and it just doesn't seem
to be working, you'll want to keep that in mind
that there are some known issues of resistance.
And then fungal feeder insects.
I mentioned earlier, these don't feed on the grain itself.
They're feeding on mold, mildew spores that pop up.
And these can be very common.
In fact, they're probably the most common
stored grain insect that I see in the state,
and they can fly in and be attracted in very large numbers.
There's about 15 or so species that
are very common in the state.
Just some examples of these, foreign grain beetle,
and we can see compared to the tip of the pen
that these things are pretty small.
We got flat grain beetles, which look very similar
to a lot of the other beetles that we talked about,
but if you look at them sideways,
they're not very thick, so relatively flat in appearance.
There's a rusty grain beetle, looks very similar.
So, again, for a lot of these,
you need to get them properly identified.
And just to reinforce that, if you identify a fungal feeder
versus a secondary or primary feeder,
we might have some different courses of action,
because for a fungal feeder,
we need to do something about that moisture control.
Get that moisture down, stop the mold, for example.
Hairy fungus beetle, yet another example
of fungal feeders that we have in the state.
We can also get some non-beetles
that pop up from time to time.
Things like booklice can be very common.
Again, they're feeding on fungal spores that are present,
so if you've got a lot of booklice
that does indicate some type of moisture issue.
And then one thing that can be very, very tiny,
grain mites.
These are about half a millimeter long,
so we're talking about a sixty-fourth of an inch,
or something along those lines, so teeny- tiny.
If you have them and you've got lots of them,
they look like walking dust.
I mean, they can be present in very high numbers,
and if you see them, it really indicates
some moisture issues.
All right, so moving on to the second part of my talk
to talk about insect management in stored grain.
And the most important thing we can do is
prevention ahead of time, things like good sanitation,
proper storage, aeration, and so on.
We'll talk some more about the details of these.
We can also do some scouting to check,
and so just as Scott mentioned, scouting for moisture
and temperature and things like that,
we want to be scouting for insects as well.
And then, if we need to,
there are a number of insecticide tools
that we have in the tool box that we can use
and choose from.
Now what's the overall story in Wisconsin?
I mentioned earlier, we really have it pretty good
compared to some of the southern parts of the country,
or some of the tropical and sub-tropical portions
of the world.
So in Wisconsin, if we have insect-free grain,
that is put in, stored into a clean bin,
and there's no insects present in that bin
and that bin is in good storage condition,
and it goes through the winter, in theory,
we should not have any insect problems
until the following summer.
So that's kind of the theoretical side of things.
The world doesn't always work according to plan,
but in Wisconsin, that's kind of the general thoughts,
because our winter is cold enough,
we're going to get that grain temperature low enough,
insects shouldn't be active or causing any type of damage.
So if we have grain that we put into a grain bin,
where do these insects come from?
Well there's a number of potential spots
they could come from.
It could be some grain still in storage,
and one of the worst things that you could do
is if you have some grain left in a bin
and you simply add new grain on top of it.
That's a major no-no, because there's a chance
that there are insects in that grain,
and they're simply going to move on up
and infest the new stuff.
Another potential source,
any place you have spilled grain,
truck, handling equipment, augers, elevators,
animal feed areas.
I mentioned earlier if you have a location
where you're feeding cattle or some other animal
on the farm, if there's spilled grain,
that could serve as a potential reservoir
for these insects and they simply have to
walk or fly over and get into a grain storage bin.
And then other nearby contaminated grains.
So if you've got a bunch of storage bins
lined up, and one is contaminated,
over time, they could potentially move over
to the other bins and infest those as well.
So any place that you've got some grain sitting around
for long periods of time,
that's a potential spot where these insects
could be coming from and living in.
So in terms of prevention,
and prevention is, really, one of the most important things
we can do.
If we're storing grain, we want to clean things out
as thoroughly as we can.
So get that grain out of the bin.
Sweep or vacuum it out if possible.
Also think about transport equipment,
trucks and combines, for example.
If there's grain that is sitting in those for months
and months, that's a potential source of these insects.
Handling equipment, so again, any place
that grain is sitting around, if we can clean that out,
that's going to help us in the long run.
Also, before we put grain into the bin,
just do a quick inspection.
If we are noticing,
hey there's a lot of holes in this bin
or some issue here, can we physically seal that up.
Cover up those little holes, fill them in somehow,
so that insects have a harder time getting in.
That will help prevent issues.
If we suspect, or just look at a history of our farm,
and we know that we have some issues
with insects, there are some insecticides that we can use
at the time we're putting grain into a bin
or afterwards, for top dressing, that we can use
to help prevent issues.
There's also some residual bin sprays.
So before we even put grain in,
if we know that in the past we had insects in there,
we have some sprays that we can spray
the inside of the bin.
That's going to help control and kill off insects
that might be in there.
And then as Scott had said, if we can store
cool, dry grain, that is one of the most important things
we can do.
If we get that moisture down to a certain level,
the insects simply can't survive,
and if we get that moisture down,
that's going to prevent mold growth,
and also, if it's cool.
Ideally, below about 60 degrees,
and as I mentioned earlier,
the critical threshold for these insects
is about 50 degrees Fahrenheit.
At that temperature and colder,
the insects aren't developing very well.
They're essentially dormant,
so the cooler we get that grain,
and if we get it cold enough, down into the 20s,
about 25 or so, a lot of these insects die.
They're not all that robust of insects.
They need it to be a fairly narrow range of temperatures
for them to do well.
So cooler and dryer grain is key.
With grain storage, I said dryer, cooler is better.
When it comes to moisture, if we have
high moisture levels, again, that's going to
cause mold to grow and develop.
That's going to draw in those fungal feeders.
Ideally, if the moisture is 12, 13%, that's going
to be at that threshold where it's pretty tough
for insects to survive.
So again, the dryer we can get that grain, the better.
And as I mentioned before, insects can't survive,
or they don't develop below about 50 degrees,
so the colder we get it, the harder they're going to have.
And, in general, every 10 degrees temperature drop,
you're going to double the storage life, roughly.
And I know Scott showed this picture earlier,
but as we see that blue bar,
that is that period, or that temperature range
where insects are essentially dormant.
So, again, below 50 degrees.
If we can get below that termperature,
insects, even if they're present,
they're not going to be doing a whole lot.
Whereas during the summer months,
if it's up in the 60s or 70s, the insects can be
very active, and if it's 70 degrees, remember,
those insects can go through two to three generations
per year, so if you miss something,
you weren't scouting for those insects,
they could reproduce fairly quickly
in a matter of a couple months.
So we want to keep it below 50.
If we get it down below freezing,
that can be very beneficial as well
to actually kill some insects.
But again, as Scott was mentioning,
we do have to monitor temperatures.
If we get too much of difference between
what's in the grain and the environment,
we can get condensation and moisture issues,
so we want to keep an eye on that.
And if we do have moisture issues, of course,
we're going to end up with moldy grain
like this, and really the way to help prevent that
and correct it is with the proper aeration techniques
that Scott talked about.
So we've harvested our grain, now what?
I mentioned earlier, if we have insect-free grain,
that's stored properly in a clean bin,
we really shouldn't have any infestation
or insect issues until the following summer, in theory.
But, remember, insects can be active above about 50 degrees
or so, so we do want to keep an eye
on things through scouting.
So there are some tools out there.
They're not complex devices at all,
but they can be very effective.
For some insects, there are pheromone traps,
and then one of the most common ones,
I'm sure everyone has seen these,
but the probe traps that you push down into the grain,
and you can come back and check.
Now in terms of scouting, you want to scout,
probably, about every two to three weeks,
and that's the longest interval you woule want to go.
During the summer, you may even want
to be doing it weekly.
And if you're going out and scouting for temperature
and other conditions, scout for insects at the same time,
and as Scott also mentioned, it's important to take notes,
because we can't necessarily remember,
did we see those insects last week
or was that six weeks ago
or three weeks ago.
So you'll want to keep a log and watch for insect activity.
During the cooler portions of the year,
you could inspect for insects about
every three to four weeks, roughly once a month or so,
just to keep an eye on things.
Again, if it's below 50, they shouldn't be doing much,
but you'll want to keep an eye out for them.
If you discover an infestation,
and I talked about this a little bit earlier,
collect some specimens,
because we need to get them properly identified.
So if you've got the resources and tools to do that,
that's great.
If you don't, get it to a crop consultant
or a county agriculture extension agent,
or send them into me at the diagnostic lab.
We can get them identified, because,
as I said earlier, if you've got fungal feeders
versus some of these secondary or primary feeders,
they may have different management approaches
that we need to do, so we need to be able
to tell the different species apart.
And then when it comes to insecticides
for dealing with these insects,
I mentioned we have residual bin sprays.
These are products we can spray onto the inside
of the bin before we fill it with grain.
That will help control any stragglers
that may still be around.
There's a number of those out there.
There are grain protectants.
These are products that we apply
to that moving grain stream as it's going
into the storage bin.
There are some surface treatments.
Essentially, we call these top dressings sometimes,
where you could treat the grain,
or you might not treat the grain,
and it's going in the bin, but you just simply
treat that upper surface, so that's an option
with some products.
And then, kind of the hammer in the tool box,
so to speak, if we get an infestation,
we have to do something about it.
One of the options that we rely on, fumigants.
And these are basically a gaseous vapor phase
that will diffuse throughout the grain bin.
It doesn't have residual, but it can be
very affective for killing off insects.
Now a few other notes I want to point out.
You need to check the pesticide label.
Remember the label is the law.
And so you need to check for any product
you're going to use, that it's okay to use it
on the particular type of grain that you're putting
into storage.
There are some products that may say
you can use it on just about anything under the sun.
There are some other ones that might say
you can only use it on corn, but not wheat, for example.
So you need to always check the label.
And then one other thing to keep in mind is
it can be helpful to chat with the buyer of the grain
beforehand.
So, for example, there are some products containing
diatomaceous earth, and you might have a buyer
that says, you know, we really don't want that
used on the grain that we're buying, because
it just makes a mess in our processing handling equipment,
and it's good to know that ahead of time.
Otherwise you might have to be looking around
for another buyer.
So those are some pieces of practical advice.
When it comes to fumigation,
just a very few, brief notes.
We're going to get better results with higher temperatures.
This has to do with the chemal activity of those fumigants,
and when it's cold, gases just don't diffuse
and move around very well.
And also, if you look at the label,
it's going to say you have to be above 40 degrees,
so in general, the warmer the temperatures,
fumigation tends to work a little bit better.
In terms of the products we have available,
if you looked back 10, 15 years ago,
we had more options, but today,
we're really left with Phosphine,
which are typically applied as these little tablets,
and then Sulfuryl Flouride, things like Profume and so on.
So those are really our only two options
that we have for fumigation.
And then, that's it for me.
I'd be happy to take any questions for,
let me back up just briefly,
for the fumigants and the insecticides,
these are, we re-did these in the
state extension crop management manual,
so the products are listed in there,
and also in the hand out today,
I list some useful resources for finding information
on these, as well as some other information
on dealing with stored grain insects.
So my contact information is up here,
and I'd be happy to take any questions from the audience.
I will also be sticking around for the morning,
so you're welcome to chat with me, individually,
if you'd like.
(applause)