Transcript pesticides.ppt

Pesticides
Pests
•
1.
2.
3.
4.
5.
Any organism
that:
competes with us
for food
Invades lawns
and gardens
Destroys wood in
houses
Spreads disease
A nuisance
Pea Aphids
Gypsy Moth Caterpillar
Emerald Ash Borer
Pesticides
• Kill pests (undesirable
orgs)
• Insecticides: kills
insects
• Herbicides: kills weeds
• Fungicides: kills
fungus
• Nematocides: kills
worms
• Rodenticides: kills
rodents
RoundUp:
Herbicide
Raid:
Insecticide
D-Con:
Rodenticide
Type: Chlorinated
Hydrocarbons
• Ex: DDT!
• Paul Muller
discovered. Won
Nobel Prize in
1948.
• Killed everything
 ranoff to H2O
(fish).
• Bioaccumulation
: fat soluble.
DDT Effects
• Slow degradation..DDT interfered with Ca+
uptakes in birds  laid weak shells.
DDT Side Notes
• Neurotoxin: opens insect Na+
channels  spasms/death.
• Resistant mutants
Human Effects
• Genotoxicity
Carcinogen?
• Endocrine
disruption
• Diabetes
• Miscarriages
Locally!
• Montrose Chemical on
Normandy in Carson
• Dumped into sewers
 emptied into White
Point Palos Verdes
• White croaker fish!
• Daily breeze 2008:
seals higher
concentrations of DDT
1962; Showed effects of
biomagnification of
DDT.
Type: Organophosphates
• Ex:
Malathion:
Insecticide
• Combat Med.
fruit fly in CA.
Sprayed in
San
Bernardino.
• Treats head
lice and
scabies!
Why Use Pesticides?
1) Saves lives.
Ex: Malaria!
Why Use Pesticides?
2) Increases food supplies
3) Increase money profits for farmers.
Case Study: Myxomatosis
• Virus as a
pesticide,
rabbits,
Australia.
• Pops went from
600-100 mill.
• Now, only 50%
effective.
Why Not Use Pesticides?
• 1) Pesticide
Treadmill: All
pests that are not
killed reproduce
 make
resistance
offspring  more
pesticide usage.
Why Not Use Pesticides?
2) Toxic to Non-target species
• Pesticides do not stay put (rain/wind runoff).
Why Not Use Pesticides
3) Human Sickness
• Acute (short-term) exposure: bleeding,
vomiting.
• Chronic (long-term) exposure: nerve
problems, brain damage, cancer, birth defects.
Pesticide Regulation
Federal
Insecticide,
Fungicide, and
Rodenticide Act
(FIFRA), 1947.
• All pesticide use
must be approved
1st by EPA.
• Pesticide makers
must test for
toxicity.
Integrated Pest Management
• Using a combo of pest control
strategies: chemicals and
alternatives.
Alternatives
1) Introduce
natural predators
of bug:
2) Put up smells
that attract bugs
away from crops
(pheromones)
3) Spray boiling
H2O
Chrysanthemums
Alternatives
4) Genetically
modify plants
to be resistant
to pests
(GMO’s)
Frost-Resistant Strawberries
(from fish gene)?
Broccoflower
Tangelo: grapefruit
and tangerine
Case Study: BT Insecticide Gene
• BT = protein found in natural soil bacteria,
Bacillus thuringensis.
• Disrupts guts of insects
• Not toxic to humans or animals
• BT gene placed in corn to protect against
corn borer.
BT gene placed in corn to
protect against corn borer
Broccoflower
Tangelo = Tang.
And Grapefruit
Advantages of GMO’s
• Less pesticides are used
• Higher nutritional content
• Possible vaccine delivery
• Less water used (on irrigation)
• Less inorganic fertilizers are used
• Enough food to feed the world!
Disadvantages of GMO’s
• Cross pollination with wild
species reduces biodiversity
• Emergence of superbugs
• Fear of unknown allergens
• Centralized control of food
production
• Poor farmers can’t afford GM
patented seeds