- Alright, Mr. D, let's talk
about pesticide mode of action.
   Very important, especially
   when you're talking about
dealing with those pests
that are out there.
 - Right, insecticides, insect
 mode of actions and a little
bit of fungicides, there are --
  Important to understand that
  there are different modes
  of action of these
  different products.
  And my first introduction
  to insect resistance was in
  was in 1978, 79 when I was
  doing some work looking at a
new product called Insecticidal
Ear Tag so in cattle to
try to prevent, to kill horn
flies and face flies and things
  like that in cattle.
  And we learned very quickly
  that the ear tags were
impregnated with a new,
relatively new class of product
   called a synthetic
   pyrethrin, or a pyrethral.
  Which is, and it worked
  real well for a year or two
  and then we started noticing
  that it didn't do as good
 a job.
  And I can remember that some
  of the folks denying that
 there was such a thing
 as insect resistance.
  And then after a very short
  while they had to admit,
   there is.
  And I also, as an extension
  agent, I can remember
   recommending Seven
   to kill fleas.
 And I remember that the dosage
 went up and after a while
 the dosage was like ten times
 what it used to be and that's
 because the fleas were
 becoming resistant to carbaryl
  which is not as common, a
  carbamate insecricide is not
 as common for resistance to
 develop, but that does happen.
  Some of the classes
  of insecticides are
  resistance happens
  quicker than others.
 But, I can give you a list of
 some of the different modes
 of action that are out there.
  And there's over 20.
   - Well is it because these
   insects are reproducing so
  quickly and there's
  so many generations?
   Is that sort of the key--
   - Of course.
  - To why resistance
  happens so quickly?
  - That and, you know, if you
  kill 98% of the populations
 you think, well that's pretty
 good, but that two percent
  reproduces--
  - [Voiceover] Pretty quick.
  - And probably most of their
  offspring are also resistant
 and then you can see
 how over a period of--
 - Doesn't take long.
 - Short period of time you can
   have all sorts of problems
   and many of these insects
 have multiple
 generations per year.
   So that can really
   create a problem.
  But, you know, a
  acetycholinesterase
  inhibitor is one,
 it inhibits, you know, causes
 of, basically a nerve gas.
  It's a nerve gas
  that kills insects.
  And that actually, these
  insecticides were developed
   from nerve gases that were
   developed back in the 30s
   and 40s or 20s and 30s
   for other uses, you know?
   Back then.
   But there's acetylcholine
   receptor antagonists,
 there's nicotine acetycholine
 receptor agonist.
- That's would be the nicatoids
we're hearing about now?
 - Right.
 - That's what that is.
 It targets the central
 nervous system.
 - They're insect growth
 regulators that inhibit ky and
   synthesis and there are--
  - So that keep them
  young or something.
- They're too young to
reproduce, you can't reproduce.
   And so, it may not kill
   you, but it keeps you from
reproducing which is important.
  - That's pretty neat stuff.
  - Molting disruptors, there
  are electron transport
 inhibitors, there's a lot of
 different products out there.
 And the take home point from
 this is, don't continue to use
 the same insecticide.
   I know when I was in the
   cattle business we would,
 for years and years and years
 cattle producers have used
a back rub, the cows can
go under and it rubs an
   insecticide on their back
   and it kills the critters.
But, very, very quickly
I learned to use
one type of product
 this year, next year I
 completely switch to another.
 I might use an organophosphate
 this year and then a
 pyrethrin next year.
 - [Voiceover] Rotate.
 - You know rotate your
 classes to prevent resistance.
  It's resistance management,
  trying to prevent creating
a super critter.
  - Shift totally your mode of
  action is what you're doing?
  - [Voiceover] Right.
   You can do that, there are
   products out there that
   you'll notice on the shelf
   that have two different
   products in them.
They have two different
modes of action in them.
  You know, kind of be careful
  using those both out at the
   same time because the
   critter that survives that
  is resistant to two
  modes of action.
 But fortunately we've
 got over 20, you know,
  we've got a lot that
  we can deal with.
 - That's a lot to choose from.
 - I don't think we're gonna
have super bugs.
- I hope not.
- Any time soon.
  - Now what about fungicides?
 - Fungicides, the same
 thing, we found that,
  and that was probably the
  last organism that I've seen
 that's developed a resistance.
 But even it's been
 out there for a while.
  I remember even back in the
  80s we were using benlate.
  We were using a real common
  benomyl, a real common
  fungicide and it was
  starting not to work as well
 as it used to.
So they've switched the classes.
   But there are strobilurins
   which is several of the
  real common heritage signas
  compus, are strobilurins
 which we have seen some fungal
 diseases develop a resistance
 to in the agricultural
 community.
  Paul got a leaf spot in
  shore beans, as an example.
  But, so, you can add another
  class, a triazole with that
  and in the agricultural
  community, you usually don't
  completely switch to another
  because some of these
 fungicides have a lot of
 strength on several diseases,
   some of them have
   strength on other disease.
  Then if you completely stop,
  you'll control this disease
 then you'll have another
 disease that'll wipe you out.
But in the agricultural
community when fungal resistance
 is encountered, most of the
 time the farmers will have to
   use a product that's got
   multiple modes of action.
  But, in your backyard for
  black spot control in roses,
 you know, you can go with
 Daconil, but there are several
things that I--
   Chlorothalonil.
   - Chlorothalonil.
   (indistinct conversation)
  - And that's a strobilurin,
  but Daconil is not.
 Strobilurin, where's Daconil?
  Chlorothalonil, it's
  a chloronitrile.
  So it's a totally different.
Same thing with blight
on tomatoes mancozeb and
 chlorothalonil are two
 fungicides and they're totally
   different classes.
Mancozeb is a dithane
four junction pentathol,
or Mancozeb and they're
in the M3 class.
Dithiocarbamate's and relatives.
   And then Captan is another
   product, it stands alone.
It's in the M4
thalidomine group and--
But keep in mind, if it has,
strobilurins, if it has strobin
  on the end of it's active
  ingredient, pyraclostrobin,
azoxystrobin, or
whatever, it's a strobi.
  And just keep in mind, don't
  just stick with the same
fungicide, mix it up if you can.
   And that's why I read off
   all of those when I list a
   bunch of products that'll
   control the disease.
- That's your take home
message so we appreciate that,
Mr. D.
