chapter 23 pest management pesticides - ddt - rachel carson - silent spring - youtube pesticides -...

Chapter 23 Chapter 23

Pest Management Pest Management

Pesticides - DDT - Rachel Pesticides - DDT - Rachel Carson - Silent Spring - Carson - Silent Spring -

YouTubeYouTube

PestsPests

Any organism that interferes in some Any organism that interferes in some way with human welfare or activitiesway with human welfare or activities

PROTECTING FOOD RESOURCES: PROTECTING FOOD RESOURCES: PEST MANAGEMENTPEST MANAGEMENT

Organisms found in Organisms found in nature (such as nature (such as spiders) control spiders) control populations of most populations of most pest species as part pest species as part of the earth’s free of the earth’s free ecological services.ecological services.

Figure 13-27Figure 13-27


We use chemicals to repel or kill pest We use chemicals to repel or kill pest organisms as plants have done for millions of organisms as plants have done for millions of years.years.

Chemists have developed hundreds of Chemists have developed hundreds of chemicals (pesticides) that can kill or repel chemicals (pesticides) that can kill or repel pests.pests. Pesticides vary in their persistence.Pesticides vary in their persistence. Each year > 250,000 people in the U.S. become ill Each year > 250,000 people in the U.S. become ill

from household pesticides.from household pesticides.


Advantages and disadvantages of conventional Advantages and disadvantages of conventional chemical pesticides.chemical pesticides.


Classification of PesticidesClassification of Pesticides

Herbicides: A toxic chemical that Herbicides: A toxic chemical that kills plantskills plants

Insecticides: A toxic chemical Insecticides: A toxic chemical that kills insectsthat kills insects


Rodenticides: A toxic chemical Rodenticides: A toxic chemical that kills rodentsthat kills rodents

Fungicides: A toxic chemical that Fungicides: A toxic chemical that kills fungikills fungi


Nematicides: A toxic chemical that Nematicides: A toxic chemical that kills nematodes (roundworms)kills nematodes (roundworms)

Algaecides: A toxic chemical that kills Algaecides: A toxic chemical that kills algaealgae


Bactericides: A toxic chemical Bactericides: A toxic chemical that kills bacteriathat kills bacteria

A toxic chemical that kills fish A toxic chemical that kills fish (unwanted species)(unwanted species)

Composed of compounds that retain their Composed of compounds that retain their toxicity for long periods of time. toxicity for long periods of time.

They work their way up the food chain They work their way up the food chain through animals and may accumulate in their through animals and may accumulate in their fatty tissues and stay indefinitely.fatty tissues and stay indefinitely.

Hard/Persistent Pesticides

DDT and many other chlorinated hydrocarbons.

Examples

Reduced-risk pesticides. They are Reduced-risk pesticides. They are short-term and don’t harm the short-term and don’t harm the environment or man.environment or man.

Soft Pesticides

soaps, oils, plant extracts, baking soda, and dish liquid.

Examples

Chemical Classes of Chemical Classes of PesticidesPesticides

Organochlorines (chlorides) Organochlorines (chlorides)

Hard/persistent Hard/persistent

Toxic in the long termToxic in the long term

Not very toxic in the short-termNot very toxic in the short-term

Ex. DDTEx. DDT

OrganophosphatesOrganophosphates Soft/not persistentSoft/not persistent Highly toxic in the short termHighly toxic in the short term

They require very specific safety equipment They require very specific safety equipment for application. for application.

Ex. Parathion --- insecticideEx. Parathion --- insecticide

CarbamatesCarbamates

Soft/not persistentSoft/not persistent

Not as toxic as the other twoNot as toxic as the other two

Most of the over-the-counter Most of the over-the-counter pesticides. pesticides.

Ex. Sevin DustEx. Sevin Dust

Historical Use of PesticidesHistorical Use of Pesticides

Natural Pesticides – pyrethrins (from Natural Pesticides – pyrethrins (from chrysanthemums); sulfur and garlicchrysanthemums); sulfur and garlic

Synthetic Pesticides – Used during and Synthetic Pesticides – Used during and after WWII and today.after WWII and today.

Benefits of Pesticide UsageBenefits of Pesticide Usage

Disease ControlDisease Control Save human lives Save human lives

Prevent insect-transmitted diseases, such Prevent insect-transmitted diseases, such as malaria (mosquito), bubonic plague (rat as malaria (mosquito), bubonic plague (rat fleas), typhus (body lice & fleas), & fleas), typhus (body lice & fleas), & sleeping sickness (tsetse fly).sleeping sickness (tsetse fly).

Food ProductionFood Production

Increase food supplies and Increase food supplies and lower food costs. lower food costs.

About 55% of the world’s About 55% of the world’s food supply is lost to pests food supply is lost to pests before (35%) and after before (35%) and after (20%) harvest. (20%) harvest.

These losses would be These losses would be worse and food prices worse and food prices would rise.would rise.

Fiber ProductionFiber Production

Protect crops such as cottonProtect crops such as cotton

Kills pests like the cotton boll weevil.Kills pests like the cotton boll weevil.

Efficiency When Compared to AlternativesEfficiency When Compared to Alternatives

Pesticides control most pests quickly and at a Pesticides control most pests quickly and at a reasonable cost.reasonable cost.

They have a long shelf lifeThey have a long shelf life

Easily shipped and appliedEasily shipped and applied

Are safe when handled properly. Are safe when handled properly.

When genetic resistance occurs, farmers can use When genetic resistance occurs, farmers can use stronger doses or switch to other pesticides. stronger doses or switch to other pesticides.

Proponents feel they are safer than the alternativeProponents feel they are safer than the alternative

Development of Safer PesticidesDevelopment of Safer Pesticides

Examples include botanicals and micro-Examples include botanicals and micro-botanicalsbotanicals

Safer to users and less damaging to the Safer to users and less damaging to the environment.environment.

Genetic engineering holds promise in Genetic engineering holds promise in developing pest-resistant crop strains. developing pest-resistant crop strains.

It is very expensive to develop these, so they It is very expensive to develop these, so they are only doing it for large-market crops like are only doing it for large-market crops like wheat, corn, and soybeans.wheat, corn, and soybeans.

Problems Associated with Problems Associated with Pesticide UsagePesticide Usage

Impact on Non-target OrganismsImpact on Non-target Organisms Pesticides don’t stay put.Pesticides don’t stay put.

The USDA says that only 2% of the insecticides The USDA says that only 2% of the insecticides from aerial or ground spraying actually reaches from aerial or ground spraying actually reaches the target peststhe target pests

Only 5% of herbicides applied to crops reaches Only 5% of herbicides applied to crops reaches the target weeds. the target weeds.

They end up in the environmentThey end up in the environment

SuperbugsSuperbugs

Genetic resistance to pesticides.Genetic resistance to pesticides.

Insects breed rapidly; within 5-10 years Insects breed rapidly; within 5-10 years (sooner in tropics) they can develop (sooner in tropics) they can develop immunity to pesticides and come back immunity to pesticides and come back stronger than before.stronger than before.

Weeds and plant-disease organisms also Weeds and plant-disease organisms also become resistant. become resistant.

At least 17 insect pest species are At least 17 insect pest species are resistant to all major classes of insecticidesresistant to all major classes of insecticides

SuperpestsSuperpests Superpests are resistant Superpests are resistant

to pesticides.to pesticides.

Superpests like the Superpests like the silver whiteflysilver whitefly (left) (left) challenge farmers as challenge farmers as they cause > $200 they cause > $200 million per year in U.S. million per year in U.S. crop losses.crop losses.


PersistencePersistence

Many pesticides stay in the Many pesticides stay in the environment for a very long time. environment for a very long time. Ex. DDTEx. DDT

BioaccumulationBioaccumulation Increase in the concentration of a chemical Increase in the concentration of a chemical

in specific organs or tissues at a level in specific organs or tissues at a level higher than normal. higher than normal.

Stored in body fat and can be passed Stored in body fat and can be passed along to offspring.along to offspring.

Usually a concern to organisms higher on Usually a concern to organisms higher on the food chain.the food chain.

Formation of New PestsFormation of New Pests Turning of minor pest into major pests.Turning of minor pest into major pests.

The natural predators, parasites, & competitors The natural predators, parasites, & competitors of a pest may be killed by a pesticide it allows of a pest may be killed by a pesticide it allows the pest population to rebound. the pest population to rebound.

EX. DDT to control insect pests on lemon trees EX. DDT to control insect pests on lemon trees caused an outbreak of a scale insect (a sucking caused an outbreak of a scale insect (a sucking insect that attacks plants) that had not been a insect that attacks plants) that had not been a problem.problem.

Food/Water ContaminationFood/Water Contamination

Pesticides run off into our water as Pesticides run off into our water as we spray for bugs & stay on our we spray for bugs & stay on our food.food.

Pesticide PoisoningPesticide Poisoning Short-term exposure to high Short-term exposure to high

levels of pesticides can result in levels of pesticides can result in harm to organs and even deathharm to organs and even death

Long-term exposure to lower Long-term exposure to lower levels of pesticides can cause levels of pesticides can cause cancer. cancer.

Children are at a greater risk Children are at a greater risk than adults.than adults.

Nausea, vomiting, and headaches.Nausea, vomiting, and headaches.

Can result in damage to the nervous Can result in damage to the nervous system & other body organs.system & other body organs.

Pesticide Poisoning

The W.H.O. estimates that more than 3 million people are poisoned by pesticides each year, & about 220,000 die.

National Cancer InstituteNational Cancer Institute Pesticides have been shown to cause Pesticides have been shown to cause

lymphomas, leukemia, brain, lung, and lymphomas, leukemia, brain, lung, and testicular cancers. testicular cancers.

The issue of whether certain pesticides The issue of whether certain pesticides cause breast cancer remains unresolvedcause breast cancer remains unresolved

Researchers have noted a correlation Researchers have noted a correlation between a high level of pesticides in the between a high level of pesticides in the breast's fatty tissue and cancer.breast's fatty tissue and cancer.

How Pesticides FunctionHow Pesticides Function

LD-50 (Median Lethal Dose)LD-50 (Median Lethal Dose) The LD-50 is the amount of pesticide it will The LD-50 is the amount of pesticide it will

take, in one dose, to kill ½ of all the target take, in one dose, to kill ½ of all the target organisms. organisms.

It is usually referring to rats & mice in a It is usually referring to rats & mice in a laboratory experiment.laboratory experiment.

Nervous SystemNervous System Some interfere with the nervous Some interfere with the nervous

system, cause uncontrollable muscle system, cause uncontrollable muscle twitching or paralysis.twitching or paralysis.

Some are nervous system poisons.Ex. Some are nervous system poisons.Ex. Spectracide, Nicotine, DDT, Dursban, Spectracide, Nicotine, DDT, Dursban, & Diazinon.& Diazinon.

Photosynthesis Photosynthesis

Some pesticides inhibit Some pesticides inhibit photosynthesis and prevent photosynthesis and prevent chlorophyll formation. chlorophyll formation.

Ex. Stampede, Pyrazon.Ex. Stampede, Pyrazon.

SmotheringSmothering

The vapors kill the pest by suffocating the The vapors kill the pest by suffocating the animal. Soap can smother soft bodies of animal. Soap can smother soft bodies of insects.insects.

Ex. flea collars, pest strip, and soap.Ex. flea collars, pest strip, and soap.

DehydrationDehydration Dehydration uses the Dehydration uses the

fossilized remains of tiny, fossilized remains of tiny, one-celled organisms called one-celled organisms called diatoms. diatoms.

It kills insects by scratching It kills insects by scratching their wax outer covering their wax outer covering and causing them to and causing them to dehydrate. This is a soft dehydrate. This is a soft pesticide.pesticide.

Inhibition of Blood ClottingInhibition of Blood Clotting

Other types of pesticides cause Other types of pesticides cause animals (especially rats) to bleed to animals (especially rats) to bleed to death by preventing their blood from death by preventing their blood from clotting.clotting.

The ideal Pesticide and the Nightmare The ideal Pesticide and the Nightmare Insect PestInsect Pest

The ideal pest-killing chemical has these The ideal pest-killing chemical has these qualities:qualities: Kill only target pest.Kill only target pest. Not cause genetic resistance in the target Not cause genetic resistance in the target

organism.organism. Disappear or break down into harmless Disappear or break down into harmless

chemicals after doing its job.chemicals after doing its job. Be more cost-effective than doing nothing.Be more cost-effective than doing nothing.

EPAEPA

The EPA & USDA are responsible The EPA & USDA are responsible for the overseeing the laws. for the overseeing the laws.

Pesticides and the Law

ResearchResearch Pesticide companies must use 3 methods to Pesticide companies must use 3 methods to

determine pesticides health threats:determine pesticides health threats: Case Reports – (made to physicians) about people Case Reports – (made to physicians) about people

suffering from adverse health effectssuffering from adverse health effects

Laboratory Investigations – (usually on animals) to Laboratory Investigations – (usually on animals) to determine toxicity, residence time, what parts of the determine toxicity, residence time, what parts of the body are affected and how the harm takes place.body are affected and how the harm takes place.

Epidemiology – (in populations of humans Epidemiology – (in populations of humans exposed) used to find why some people get sick exposed) used to find why some people get sick while others do notwhile others do not

Days to HarvestDays to Harvest

The last day you can spray crops The last day you can spray crops before you harvest them for human before you harvest them for human consumption.consumption.

RestrictionsRestrictions The EPA sets a tolerance level specifying The EPA sets a tolerance level specifying

the amount of toxic pesticide residue that the amount of toxic pesticide residue that can legally remain on the crop when the can legally remain on the crop when the consumer eats it.consumer eats it.

FFDCAFFDCA

Federal Food, Drug, and Cosmetic Federal Food, Drug, and Cosmetic ActAct

Strengthened in 1996 Strengthened in 1996 Sets pesticide tolerance levelsSets pesticide tolerance levels

Label RequirementsLabel Requirements the brand name the brand name the ingredient statementthe ingredient statement the percentage or amount of active ingredient(s) by weightthe percentage or amount of active ingredient(s) by weight the net contents of the containerthe net contents of the container the name and address of the manufacturerthe name and address of the manufacturer Registration and establishment numbersRegistration and establishment numbers Signal words and symbolsSignal words and symbols Precautionary statementPrecautionary statement Statement of practical treatmentStatement of practical treatment Environmental hazard statementEnvironmental hazard statement Classification statementClassification statement Directions for useDirections for use Re-entry statement Re-entry statement Harvesting and/or grazing restrictionsHarvesting and/or grazing restrictions Storage and disposal statement. Storage and disposal statement.

FIFRAFIFRA The Federal Insecticide, The Federal Insecticide,

Fungicide & Rodenticide ActFungicide & Rodenticide Act It was first established in It was first established in

1947 & revised as recently 1947 & revised as recently as 1996. as 1996.

States what must be on a States what must be on a pesticide label & requires pesticide label & requires registration of all pesticides.registration of all pesticides.

FQPAFQPA

Food Quality Protection ActFood Quality Protection ActEstablished in 1996 Established in 1996 Amends both FIFRA and FFDCA.Amends both FIFRA and FFDCA.

Pesticide Protection Laws in the U.S.Pesticide Protection Laws in the U.S.

Government regulation has banned a number of Government regulation has banned a number of harmful pesticides but some scientists call for harmful pesticides but some scientists call for strengthening pesticide laws.strengthening pesticide laws. The Environmental Protection Agency (EPA), the The Environmental Protection Agency (EPA), the

Department of Agriculture (USDA), and the Food and Department of Agriculture (USDA), and the Food and Drug Administration (FDA) regulate the sales of Drug Administration (FDA) regulate the sales of pesticides under the Federal Insecticide, Fungicide pesticides under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA).and Rodenticide Act (FIFRA).

The EPA has only evaluated the health effects of The EPA has only evaluated the health effects of 10% of the active ingredients of all pesticides.10% of the active ingredients of all pesticides.

Risk & DecisionRisk & Decision

Individuals Matter: Rachel CarsonIndividuals Matter: Rachel Carson

Wrote Wrote Silent SpringSilent Spring which introduced the which introduced the U.S. to the dangers U.S. to the dangers of the pesticide DDT of the pesticide DDT and related and related compounds to the compounds to the environment.environment.

Figure 13-AFigure 13-A

Silent SpringSilent Spring Silent Spring Silent Spring heightened public awareness heightened public awareness

and concern about the dangers of and concern about the dangers of uncontrolled use of DDT and other uncontrolled use of DDT and other pesticides, including poisoning wildlife and pesticides, including poisoning wildlife and contaminating human food supplies.contaminating human food supplies.

Integrated Pest Management (IPM)

IPM

Case Study: Integrated Pest Case Study: Integrated Pest Management: A Component of Management: A Component of

Sustainable AgricultureSustainable Agriculture

An ecological approach to pest control uses a An ecological approach to pest control uses a mix of cultivation and biological methods, and mix of cultivation and biological methods, and small amounts of selected chemical small amounts of selected chemical pesticides as a last resort.pesticides as a last resort. Integrated Pest Management (IPM)Integrated Pest Management (IPM)

Other Ways to Control PestsOther Ways to Control Pests

There are cultivation, biological, and There are cultivation, biological, and ecological alternatives to conventional ecological alternatives to conventional chemical pesticides.chemical pesticides. Fool the pest through cultivation practices.Fool the pest through cultivation practices. Provide homes for the pest enemies.Provide homes for the pest enemies. Implant genetic resistance.Implant genetic resistance. Bring in natural enemies.Bring in natural enemies. Use pheromones to lure pests into traps.Use pheromones to lure pests into traps. Use hormones to disrupt life cycles.Use hormones to disrupt life cycles.

Cultural MethodsCultural Methods

PhysicalPhysical

This includes rotating between different This includes rotating between different crops, selecting pest-resistant varieties, crops, selecting pest-resistant varieties, planting pest-free rootstock, and planting pest-free rootstock, and vacuuming up harmful bugs.vacuuming up harmful bugs.

Traditional “EcoFarmer”Traditional “EcoFarmer”

Each crop is evaluated as parts of an Each crop is evaluated as parts of an ecological system. ecological system.

A control program is developed that A control program is developed that includes a mix of cultivation, biological, includes a mix of cultivation, biological, and chemical methods applied in proper and chemical methods applied in proper sequence with the proper timing.sequence with the proper timing.

Biological MethodsBiological Methods


Biological pest Biological pest controlcontrol: Wasp : Wasp parasitizing a gypsy parasitizing a gypsy moth caterpillar.moth caterpillar.


Predators/ParasitesPredators/Parasites

Using natural predators & parasites Using natural predators & parasites to control population of pests.to control population of pests.

DiseasesDiseases

Using disease organisms (bacteria Using disease organisms (bacteria and viruses) to control pests.and viruses) to control pests.

Natural RepellantsNatural Repellants

Garlic, sulfur, pyrethrins (from Garlic, sulfur, pyrethrins (from chrysanthemums) to help control chrysanthemums) to help control pests.pests.

Type of CropsType of Crops Switching from vulnerable Switching from vulnerable

monocultures to intercroping, monocultures to intercroping, agroforestry, and polyculture, which agroforestry, and polyculture, which use plant diversity to reduce losses to use plant diversity to reduce losses to pests.pests.

Photodegradable PlasticsPhotodegradable Plastics

Using plastic that Using plastic that degrades slowly degrades slowly in sunlight to in sunlight to keep weeds from keep weeds from sprouting sprouting between crops.between crops.

PheromonesPheromones

Synthesized bug sex attractant used to lure Synthesized bug sex attractant used to lure pests into traps or attract their predators.pests into traps or attract their predators.

Genetic MethodsGenetic Methods


Genetic Genetic engineering can engineering can be used to be used to develop pest develop pest and disease and disease resistant crop resistant crop strains.strains.

Both tomato plants were exposed to destructive caterpillars. The genetically altered plant (right) shows little damage.


Resistant CropsResistant Crops Plants and animals that are Plants and animals that are

resistant to certain pest resistant to certain pest insects, fungi, and diseases insects, fungi, and diseases can be developed.can be developed.

This can take 10 to 20 years.This can take 10 to 20 years. Genetic engineering is now Genetic engineering is now

helping to speed up this helping to speed up this process through the process through the development of transgenic development of transgenic crops.crops.

SterilizationSterilization

Males of some insect species can be raised Males of some insect species can be raised in the laboratory, sterilized by radiation or in the laboratory, sterilized by radiation or chemicals, and released into an infested area chemicals, and released into an infested area to mate to mate unsuccessfullyunsuccessfully with fertile wild with fertile wild females. females.

Males are sterilized rather than females Males are sterilized rather than females because the male insects mate several times, because the male insects mate several times, whereas the females only mate once.whereas the females only mate once.

Fig. 13-30, p. 299

What Can You Do?

Reducing Exposure to Pesticides

• Grow some of your food using organic methods.

• Buy organic food.

• Wash and scrub all fresh fruits, vegetables, and wild foods you pick.

• Eat less or no meat.

• Trim the fat from meat.

chapter 23 pest management pesticides - ddt - rachel carson - silent spring - youtube pesticides -...

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household pesticides

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hardpersistent pesticides

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garlic synthetic pesticides