-
In 1845, Ireland's vast potato fields
were struck by an invasive fungal disease
-
that rapidly infested this staple crop.
-
The effect was devestating.
-
One million people died of famine,
-
and over a million more were forced
to leave Ireland.
-
Nowadays, we avoid such agricultural
catastrophes with the help of pesticides.
-
Those are a range of manmade chemicals
that control insects,
-
unwanted weeds,
-
funguses,
-
rodents,
-
and bacteria
-
that may threaten our food supply.
-
They've become an essential part
of our food system.
-
As populations have grown,
monoculture, single crop farming,
-
has helped us feed people efficiently.
-
But it's also left our food
vulnerable to extensive attack by pests.
-
In turn, we've become more dependent
on pesticides.
-
Today, we annually shower over 5 billion
pounds of pesticides across the Earth
-
to control these unwanted visitors.
-
The battle against pests,
especially insects,
-
has marked agriculture's long history.
-
Records from thousands of years ago
-
suggest that humans actively burned
some of their crops after harvest
-
to rid them of pests.
-
There's even evidence from ancient times
that we recruited other insects to help.
-
In 300 A.D., Chinese farmers specially
bred ferocious predatory ants
-
in orange orchards
to protect the trees from other bugs.
-
Later, as large-scale farming spread,
-
we began sprinkling arsenic, lead,
and copper treatments on crops.
-
But these were incredibly toxic
to humans as well.
-
As our demand for more,
safer produce increased,
-
so did the need for effective chemicals
-
that could control pests
on a grander scale.
-
This ushered in the era
of chemical pesticides.
-
In 1948, a Swiss chemist named
Paul Hermann Müller
-
was awarded a Nobel Prize
for his discovery
-
of dichlorodiphenyltrichloroethane,
also known as DDT.
-
This new molecule had unparalleled power
to control many insect species
-
until the 1950s,
when insects became resistant to it.
-
Worse, the chemical actually drove
dramatic declines in bird populations,
-
poisoned water sources,
-
and was eventually found to cause
long-term health problems in humans.
-
By 1972, DDT had been banned
in the United States,
-
and yet traces still linger
in the environment today.
-
Since then, chemists have been searching
for alternatives.
-
With each new wave of inventions,
they've encountered the same obstacle -
-
rapid species evolution.
-
As pesticides destroy pest populations,
-
they leave behind
only the most resistant individuals.
-
They then pass on their
pesticide-resisting genes
-
to the next generation.
-
That's lead to the rise of super bugs,
-
such as the Colorado potato beetle,
-
which is resistant to over
50 different insecticides.
-
Another downside is that other bugs
get caught in the crossfire.
-
Some of these are helpful predators
of plant pests or vital pollinators,
-
so erasing them from agriculture
wipes out their benefits, too.
-
Pesticides have improved over time
-
and are currently regulated by strict
safety standards,
-
but they still have the potential
to pollute soil and water,
-
impact wildlife,
-
and even harm us.
-
So considering all these risks,
why do we continue using pesticides?
-
Although they're imperfect,
-
they currently may be our best bet
against major agricultural disasters,
-
not to mention mosquito-born diseases.
-
Today, scientists are on a quest for
alternative pest control strategies
-
that balance the demands
of food production
-
with environmental concerns.
-
Nature has become a major source
of inspiration,
-
from natural plant and fungal chemicals
that can repel or attract insects,
-
to recruiting other insects
as crop bodyguards.
-
We're also turning to high-tech solutions,
like drones.
-
Programmed to fly over crops,
-
these machines can use
their sensors and GPS
-
to carry out more targeted sprays
-
that limit a pesticide's wider
environmental impact.
-
With a combination
of biological understanding,
-
environmental awareness,
-
and improved technologies,
-
we have a better chance of finding
a holistic solution to pests.
-
Chemical pesticides may never shake
their controversial reputation,
-
but with their help,
-
we can ensure that
agricultural catastrophes
-
stay firmly in our past.