Transcript Pest Control

Pest Control
Chapter 12
APES 2010
What are pesticides?
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Chemicals that kill
pests
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Biocides- kill wide
range of pests
Herbicides- kill plants
Insecticides- kill
insects
Fungicides- kill fungi
History of Pesticides
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Every culture has used pesticides
Modern era of pesticides began in
1934 with development of DDT
(Dichloro-DiphenylTrichloroethane)
Used in WWII to control parasites
& tropical disease
Was cheap, stable, soluble in oil,
easily spread over wide areas.
High toxicity for target organismskills 90% of target organisms in
single application
It was the “magic bullet”- the
answer to our prayers… or was it?
History of Pesticides
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Indiscriminate & excessive
use of pesticides has caused
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Damage to ecosystems
Harm to human health
Creation of “superbugs”
¾ of all pesticides are used in
Most Developed Countries
(MDC) but rates in LDC are on
the rise by 7-8%.
DDT was banned in US in the
1970’s. We can now only use
it in emergencies.
DDT is still used in many other
countries- especially for control
of mosquitoes.
Children playing in DDT clouds at
beach.
Types of Pesticides
classified based on chemical structure
Inorganic Pesticides
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Arsenic, copper,
lead, mercury
Highly toxic &
indestructable
Neurotoxin- single
dose can cause
damage
May be used on
seeds to deter
rodents
Arsenic poisoning from
infected water sources in
Bangladesh
Types of Pesticides
Natural organic
pesticides
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Nicotine, rotenone
Botanicals
From plants
Types of Pesticides
Fumigants
3.
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Carbon tetrachloride,
carbon disulfide
Become gases
easily & penetrate
easily
Used to sterilize soil
or deter rodent
infestation in stored
grain
So dangerous,
mostly banned
Types of Pesticides
Chlorinated
Hydrocarbons
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DDT, chlordane, aldrin,
dieldrin, toxaphene,
paradichlorobenzene
(mothballs),
Block nerve signals
Fast & toxic,
carcinogenic
Biomagnify- stay in
ecosystem
Toxaphene kills goldfish
at 5 ppb- one of the
highest toxicities for any
compound
Types of Pesticides
Organophosphates
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Parathion, malathion,
DDVP, TEPP
From nerve gas research
Extremely toxic to
mammals, birds, & fish
One drop of TEPP on
skin is lethal
Quickly degrade so much
less persistent in
environment
Types of Pesticides
Carbamates
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Carbaryl, Mirex
Similar to
organophosphates
Very toxic to bees
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If bees die, our crop
yields will decrease
drastically due to lack
of pollination
Types of Pesticides
Microbial agents or
Biological controls-
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using live organisms
or their toxins
instead of pesticides
Bacillus thuingiensis
(Bt)- kills beetles,
caterpillars by
destroying their
digestive tract
Parasitic wasps
Ladybugs eat aphids
Viruses
Benefits of Pesticides
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Reduce disease transmission by insect vectors (DDT
sprayed to kill mosquitoes & prevent malaria, when
stopped in 1964, malaria reappeared immediately)
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Which is more important? Protecting people or the
environment?
If you had to choose between contracting masses of worms that
will make you go blind before the age of 30 or a small chance of
cancer due to pesticide exposure it you live to 50 or 60, which
would you choose?
Reduce crop losses by two-thirds.
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Farmers save $3-$5 for every $1 they spend on pesticides.
Lowers costs and increases crop quality
Problems with Pesticides
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Non-target organisms affected
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Potato aphid spraying killed
migrating robins
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Insecticide spraying in CA killed
salmon
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Honeybees disappearing
Resistant individuals will develop due
to natural selection
Pesticide is killing off natural
predators that help control bad
populations
Limited useful lifespan- can move far
from original application spot (next
slide)
Persistant organic pollutants (POP’s)
are very long lasting and dangerous.
Banned in most countries but
persistent in soil & water
Affect Human Health (see slide 15)
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Acute- poisoning & illness
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Chronic- cancer, birth defects,
degenerative diseases
Pest resurgence leads to the use
of higher doses or more toxic
chemical use
The Grasshopper Effect
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Many chemicals like
chlorinated hydrocarbons
evaporate from water & soil in
warm areas & condense &
precipitate in colder regions.
This happens over & over,
“hopping” northward until it
collects in polar regions.
Affecting top predators (polar
bears, whales, & humans)
Some carcasses have to be
treated as toxic waste they are
so “infected” with pesticide.
Be familiar with “The Dirty
Dozen”- Table on
toxin review sheet
About Human Health…
 Yaqui
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children in Mexico tested…
Foothills children age 4-5 not exposed to
much pesticide
Valley children age 4-5 repeatedly exposed
Alternatives to Pesticides
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Crop rotation keeps
pest population low.
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Using cover crops
keeps weeds down
Provide habitat for
natural predators
(plant trees along
edge of farm for birds
which will eat bugs &
provide windbreak
which prevents
erosion)
Alternatives to Pesticides
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Biological controls- natural
predator
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Bacillus thuringiensis (Bt)- kills
beetles & caterpillars
Ladybugs, praying mantises,
wasps
Ducks & geese in fields will
eat insects & weed seed.
Planting garlic or marigolds
can deter pests.
Release of sterilized males
(screwworms)
Release of artificial hormones
can disrupt life cycles
(mosquitoes)
Alternatives to Pesticides
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Integrated Pest Management
(IPM)- use preventative measures
to encourage growth & diversity
with minimal use of chemical
pesticides
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Vacuuming bugs off crops
Trap crops- mature before rest of
field to attract pests, then sprayed
heavily, destroy trap crop to
prevent spread to people or “real”
crop.
Educating farmers- In Indonesia
farmers were spraying fields about
3x a week whether planthopper
pest was present or not- made
them pesticide resistant. By
educating farmers about natural
predators and using pesticides
sparingly, helped increase crop
yields & save $ on pesticide
Who regulates pesticide usage?
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Environmental Protection Agency (EPA)
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Regulates sale & usage under Federal Insecticide, Fungicide,
& Rodenticide Act (FIFRA) which mandates the “registration” of
all pesticide products.
Determines which pesticides are safe to use for humans &
environment
Sets tolerance levels for residues that may remain in or on foods
marked in U.S. This falls under the Federal Food, Drug, and
Cosmetic Act (FFDCA).
Department of Agriculture (USDA) & Food & Drug
Administration (FDA) enforce pesticide use & tolerance
limits set by EPA. Can seize & destroy food shipments
that violate.
What can you do at home?
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Plant grass that can compete with weeds. Don’t worry about the
weeds- don’t we all love dandelions!
Repair screen doors to keep bugs out. Caulk windows, doors, etc to
keep rodents, roaches, ants out
Clean up spills & remove garbage regularly; use flypaper, use borax
for roaches
Kill aphids & other plant bugs by spraying with dilute detergent
solution. Order ladybugs or praying mantis cocoons.
Use beer to drown slugs in gardens
Remove all sources of stagnant water to deter mosquitoes.
If you must use pesticides use them in small amounts & only when
necessary; try not to use sprayers
Create mulch from your veggie scraps & kitchen waste & use as
mulch to deter weeds.