hi students welcome to video 20 on the
pesticide dilemma so I'm just some facts
for your information you don't need to
write any of this down 3 million metric
tons of pesticides are used annually on
Earth's 25% in the US or you used in our
houses so houses Gardens lawns playing
field swimming pools golf courses that's
where most of the pesticides are 1/4 of
the pesticides go on the rest of it are
going to be for agricultural purposes
and the average u.s. homeowner applies
about 2 to 6 times more per acre than a
farmer would because we think that we
shouldn't use more in reality it doesn't
take as much as people actually think
it's a little bit of history before the
1950s farmers actually used arsenic lead
mercury things that they got from
minerals these were our first generation
pesticides in most cases as you can
imagine not the best thing in the world
we started using synthetic pesticides
things that were made in the lab and
this doubled our food production in
developed countries and it increased it
by 120 percent in developing countries
so these chemicals have been really good
in terms of feeding the population of
the world remember those almost
seven-and-a-half billion people that we
have otherwise we would not be able to
do that so here are some of the
different classes of pesticides I don't
really think you need to right this day
on most of them are pretty obvious and
insecticides kill insects herbicides for
weeds fungicides for fungi nematodes for
round worms nematodes rodenticides kill
rodents alga sods kill algae and larvae
sods kill larvae so something you need
to know narrow versus broad spectrum
Paris pesticides so a narrow spectrum is
going to kill only the target species
broad spectrum is going to kill a
variety or a lot of different species so
narrow spectrum is good if you have a
specific target that you know is the
problem broad spectrum might be good if
you're not really sure and you just have
problems with insects eating your crops
which you
have a specific one on so narrow respect
spectrum is more what we want to use
because if you use the broad spectrum
it's gonna kill everything even
including the good things involved so
some of the disadvantages and advantages
of course with everything you need to
know environmental economic social
advantages and disadvantages and be able
to discuss it some advantages are it
does save lies because it allows us to
grow more food and that in terms saves a
lot of lives people don't die from
starvation if you can grow more crops it
is profitable so it gets you a lot more
money they tend to work really fast so
they'll kill off the insects really
quickly and it is safe if used properly
and you don't spray them you know more
so than what you would actually need on
some disadvantages it does promote
genetic resistance something we call the
pesticide treadmill is this idea that
you know I spray chemicals to get rid of
this pest but then the pest becomes
resistant so I spray more of the
chemicals I spray a higher concentration
of the chemicals and then the pest
becomes Express and again so you have
this cycle on this treadmill if you
would of continuing to having to use
more harsh chemicals and more
concentrated chemicals to kill the same
pests I also end up killing native pests
that are good and I can create like
these superbugs with that genetic
resistance I also pollute the
environment the air the water and it can
harm people and wildlife if used
inappropriately a little bit of a little
fact down here for you the pesticide
industry declares that the health risks
are insignificant compared with the
benefits which of course they would say
that so some harmful effects on the
ecosystem pesticides can be persistent
meaning that they remain in the
environment for many many years they can
also by accumulate moving up the food
chain so each organism is going to have
more of the persistent pesticides such
as DDT in their bloodstream then you
know lower things on the bottom that
we've talked about before with
biomagnification children and the
elderly like usual are the most at risk
but it's a greater threat to children
because they're playing on the floor
they're outside
playing on the lawn maybe not as much
now they're inside on their iPads but
you know saving you from pesticides isit
assumed but their brains and their
bodies are still developing and so as
they're getting around on the floor in
the lawns you know they're inhaling
these things and it's causing them to
have issues this does affect your
intelligence and motor skills has been
shown to even and older people possibly
be linked to Parkinson's disease and so
we're investigating that right now what
is the ideal pesticide well it would
kill only the target species um it would
disappear quickly an environment so it
wouldn't be persistent
it would also break down into something
harmless because some things do not they
actually break down into more harmful
substances it would also not cause
genetic resistance and right now there
is no such thing on the market so if you
can design this and market this you
would make millions if not billions of
money if you could make this ideal
pesticide I'm specifically DDT this is
one that was used a lot in the 40s the
60s we were used it in agriculture and
we used it in disease in areas that are
ridden with diseases because it can kill
things like mosquitoes so if you're
living in some countries like South
America Africa some of the Middle East
areas to these mosquitoes are really
awful and they transmit malaria which is
a disease that causes a lot of deaths
per year so if you spray DDT it will
kill the mosquito and prevent you from
getting malaria but then you're left
with the DDT so it's kind of a trade-off
here would you rather have the pesticide
poisoning and the neurological problems
that come with that or would you rather
have malaria which could cause you to
die much much earlier than you probably
would normally um so DT is very
persistent the other problem with it is
it breaks down to something even more
toxic which is dde so you know we want
something that breaks down into harmless
things not something that's worse
and we know DDT accumulates and bio
magnifies in the food chain so what does
it do specifically well it blocks
calcium formation
in bird eggs this was the thing that
Rachel Carson kind of figured out why is
the spring silent if you remember her
silent spring book um the eggs are then
thin because they can't make the calcium
and so they break really easily so in
other words the eggs do not last long
enough for the baby birds to actually
survive and hatch they basically end up
like cracking open really easy for
predators to get to them and this causes
the ball eagle to go almost extinct
luckily we kind of reversed this problem
and we realized that DDT was doing this
so again please remember Rachel Carson
and DDT her book was Silent Spring this
is just kind of some four year
information stuff over here in 1958 it
was sprayed to control mosquitoes near
bird sanctuaries and we noticed that the
birds were dying and this is a quote
from the book for the first time in the
history of the world every human being
is now subjected to dangerous chemicals
from the moment of conception until
birth so this is you know we see things
in our system already and we're not even
always sure what they do but you know
usually if you got chemicals in your
body from outside sources not going to
be a good thing so some opposition to
her book the public was really you know
embracing of this they really liked the
book they realized what was happening
but the chemical industry is you can
imagine not so much they you know use a
lot of money $250,000 which back then
was a lot more money than it would be
today to discredit her and they called
her or they said as a woman she was
incapable of understanding the highly
scientific and technical subject of
pesticides I'm sorry ladies but that's
the way that women were looked at back
then now we know better and we would not
you know hopefully we would not say such
things even though sometimes it still
happens um unfortunately 18 months after
she published the book Rachel Carson
ironically died from cancer possibly
from pesticide exposure but we can't
really say that so looking at DDT in the
US now it was banned in 1973 however we
still actually
make it and we send it to developing
nations so they can use it to fight
malaria and to also grow crops we are
the largest manufacturer of DDT and just
because we're not actually putting it on
our food does not mean that it doesn't
still get in our food so we import food
if we're importing from place where we
are sending DDT then you bet there's DDT
on that food it also travels through
wind belts around the world because it
gets sprayed and put in the atmosphere
so it's not just you know over in some
other country and it's not affecting us
at all it is still impacting us so the
last little thing we're going to talk
about is integrated pest management what
can we do besides putting chemicals in
our food so these are your four
strategies for integrated pest
management the first thing is
cultivation method so we don't do things
like crop rotation contour plowing you
know adding nutrients to the soil with
fertilizer you know manure those sorts
of things that we can do and if we're
doing things you know polyculture
instead of monoculture that will
decrease on the amount of pests that we
have so that's our first step um if
you're doing crop rotation and you still
have problems then now you can
mechanically remove pests so that's what
you see this farmer down here doing he's
actually walking around with a net and
he's capturing bugs this over here is
the same kind of thing except it's it's
in place and bugs get stuck to it you've
probably seen those before
if that doesn't work then you do
biological controls what that means as
you bring in the predator of the pests
so maybe bring in birds or you try to do
something that will bring them in and
they will kill off the insects
themselves your very last resort is
going to be chemical control so this is
the very last thing that I want to do
I've tracked cultivation mechanical and
biological controls and nothing has
worked so now I want to spray pesticides
but again I want to do it you know smart
so I don't want to use more than I have
to I use the very limited amount that I
need and some laws regarding pesticides
you have for the federal insecticide
fungicide and rodenticide act basically
this is the EPA creating tolerance level
four different pesticides and trying to
manage pesticides alright that's it
bring your questions tomorrow and be
ready for a quick
