Get out your HW & In your notes…Get out your HW & In your notes…

Do you think that we should use Do you think that we should use pesticides?pesticides?

What applications do you believe What applications do you believe pesticides are acceptable for, if any?pesticides are acceptable for, if any?

PesticidesPesticides What is a Pest?What is a Pest? Any organism that is Any organism that is

destructive or destructive or annoying (mostly annoying (mostly weed and insects).weed and insects).

What are some What are some Examples:Examples:

Mosquitoes carry Mosquitoes carry malaria, grasshopper malaria, grasshopper destroys crop, rats destroys crop, rats carry disease.carry disease.

What is a Pesticide? What are 2 Types What is a Pesticide? What are 2 Types of Pesticides?of Pesticides?

PesticidePesticide - any chemical used to kill pests - any chemical used to kill pests• insecticideinsecticide - kills insects - kills insects• herbicideherbicide - kills plants - kills plants

Pest ManagementPest Management Pest management:Pest management:

ways to control ways to control pestspests

HistoryHistory• 1800’s - used early 1800’s - used early

pesticidespesticides containing natural containing natural minerals such as minerals such as sulfur, arsenic, sulfur, arsenic, copper, lead, and copper, lead, and mercury.mercury.

History ContinuedHistory Continued World War II - started World War II - started

using man-made using man-made chemicals called chemicals called chlorinated chlorinated hydrocarbonshydrocarbons in order to in order to create a nerve gas. They create a nerve gas. They were tested on insects. were tested on insects.

They worked and were They worked and were cheap to make. Vastly cheap to make. Vastly used for agricultureused for agriculture

EX. DDTEX. DDT

ProblemsProblems Growing monocultures attracts many insect Growing monocultures attracts many insect

pests of that plant. Pesticides were therefore pests of that plant. Pesticides were therefore used more often.used more often.

Problems- What happens when Problems- What happens when you spread a pesticide?you spread a pesticide?

Kills most things including the organisms that Kills most things including the organisms that are helpful (only 1 out of every 8 insect species are helpful (only 1 out of every 8 insect species are pests). are pests).

Problems- Where do the Pesticides go?Problems- Where do the Pesticides go? Many pesticides Many pesticides persistpersist (don’t decompose) in (don’t decompose) in

the environment. They stay in soil or runoff into the environment. They stay in soil or runoff into water. water.

Problems- Why is it bad if we constantly kill Problems- Why is it bad if we constantly kill some of the pests? Think Evolution…some of the pests? Think Evolution…

Overtime insects became resistant (survived Overtime insects became resistant (survived and passed that trait to the next generation) to and passed that trait to the next generation) to the pesticide. More pesticide was used. the pesticide. More pesticide was used.

Problems- What is Problems- What is Bioaccumulation?Bioaccumulation?

Pesticides Pesticides bioaccumulatebioaccumulate- pesticides are - pesticides are absorbed and accumulate in the fat of animals absorbed and accumulate in the fat of animals through the food chain.through the food chain.

Problems: DDTProblems: DDT DDT was very DDT was very

persistent and affects persistent and affects bird reproduction bird reproduction through through bioaccumulation.bioaccumulation.

Some eggs didn’t Some eggs didn’t develop or the eggs develop or the eggs shells were very thin shells were very thin causing them to crack.causing them to crack.

Bald eagles and Bald eagles and ospreys became ospreys became endangered.endangered.

Rachel Carson- Rachel Carson- Silent SpringSilent Spring

Rachel Carson Rachel Carson writes “Silent writes “Silent Spring” about the Spring” about the risks of pesticides - risks of pesticides - DDT is banned.DDT is banned.

Other Other hydrocarbons were hydrocarbons were still used still used (Heptachlor and (Heptachlor and Chlordane) (read Chlordane) (read pgs 269 – 272)pgs 269 – 272)

What are 2 Ways Pesticides can be What are 2 Ways Pesticides can be Used?Used?

Selective pesticideSelective pesticide - only kills one pest. - only kills one pest. Broad spectrum pesticideBroad spectrum pesticide - can kill many - can kill many

at once plus everything else.at once plus everything else.

What the EPA does Now…What the EPA does Now…

Now the EPA and FDA Now the EPA and FDA evaluate the benefits evaluate the benefits and risks of pesticides and risks of pesticides to all people involved to all people involved (workers and (workers and consumers)consumers)

EPA requires signal EPA requires signal words and precautions words and precautions on labels) – pgs 262-on labels) – pgs 262-263263

What the EPA does Now…What the EPA does Now…

EPA sets EPA sets tolerance levelstolerance levels- - • maximum amount of pesticide residue allowed in maximum amount of pesticide residue allowed in

or on food.or on food. Maximum contaminant levels (MCLs) Maximum contaminant levels (MCLs)

• are tolerance levels for water and are lower than are tolerance levels for water and are lower than food since more water is consumedfood since more water is consumed

*Even with the EPA regulations, there may be *Even with the EPA regulations, there may be some risks to you and the environment.some risks to you and the environment.

How do the following pictures make How do the following pictures make you feel about DDT?you feel about DDT?

MalariaMalaria

Malaria kills Malaria kills more than a more than a million people million people worldwide worldwide each year—90 each year—90 percent of percent of them in Africa; them in Africa; 70 percent 70 percent children under children under the age of the age of five. five.

You Decide…You Decide…

Do the risks out weigh the benefits?Do the risks out weigh the benefits?