Pesticides and Pest Control

Mrs. Cook

Environmental Science

Objectives:

• Define Pesticides• Discuss the Pro’s and Con’s of Pesticide use• Understanding of Regulations• Alternatives

Types and Uses

A Pest is any species that

- invades lawns and gardens

- destroys wood in houses

- competes with us for food

- spreads disease

- simply a nuisance

Types of Pesticides

• Used to kill organisms we consider undesirable:- Insecticides (insect killers)- Herbicides (weed killers)- Fungicides (fungus killers)- Nematocides (roundworm killers)- Rodenticides (rat and mouse killers)

-http://www.domyownpestcontrol.com/ - http://www.pestproductsonline.com

http://www.youtube.com/watch?v=jCQ9hxI9Q20

1st Generation Pesticides

• Sulfur: Used pre-500B.C• Natural Pesticides:

-Nicotine- from tobacco leaves

-Sulfate

-Pyrethrum- from chrysanthemum flowers

-Rotenone- from roots of various tropical forest legume

-Chemicals borrowed from plants that had been defending themselves from insects

1st Generation Pesticides

• Toxic Chemicals (by the 1400s)• People were applying toxic compounds of Arsenic,

Lead and Mercury to crops as insecticides. • Abandoned in the late 1920s when the increasing

number of human poisonings and fatalities prompted a search for less toxic substitutes.

• Traces of these non-degradable toxic metal compounds are still being taken up by tobacco, vegetables, and other crops grown in soil dosed with them long ago.

2nd Generation Pesticides

• Major pest control revolution began in 1939, when Paul Muller discovered DDT (dichlorodiphenyltrichloroethane)

• He received the Nobel Prize in 1948 for his discovery.

• 1950- pesticide use had risen more than 50x.

• Most of today’s pesticides are more than 10x as toxic as those used in the 1950s

• 2.5 million tons are used yearly world wide.

http://www.youtube.com/watch?v=gtcXXbuR244&playnext=1&list=PL153F59E8B8619158&feature=results_main

Rachel Carson’s Silent Spring• Rachel Carson (1907-1964)• Summary: • Once there was a town in the United States of America

where all living things existed in harmony. Thriving farms surrounded the town and every spring there were fruits and flowers in abundance. When people traveled to the area, they enjoyed the variety of plants. This was a land that was beautiful in spring and in winter. Suddenly, something happened to make everything start to die. No one could account for the strange kinds of symptoms people, birds, and animals started displaying. Many creatures died. Sometimes children would be outside playing and suddenly they would be stricken with something and die only a few hours later. People wondered what had happened to the birds. The birds that remained were often so sickly that they couldn’t fly. Chickens still laid eggs, but the eggs didn’t hatch. The apple trees put out blossoms, but no bees came to pollinate them. The countryside that once looked so pretty now looked dry and withered. People noticed a fine, white dust had settled all over the leaves and in the gutters of their houses. The problem with this land didn’t come from witchcraft, but from the people themselves.

Rachel Carson’s Silent Spring

• Rachel Carson was credited with helping to start the Environmental Movement.

• Silent Spring has been featured in many lists of the best nonfiction books of the twentieth century.

http://www.youtube.com/watch?v=T_Njv5Ygg0g

http://www.youtube.com/watch?v=ls-JY74M2Ik

http://www.youtube.com/watch?v=M0odbzri_Ak

“The day they parachuted cats into Borneo!”

Ecosystem Disaster

The end of the story…

In the 1950's The World Health Organization (WHO) financed and supported the first ever team of over 14,000 parachuting cats into Borneo!

Instructions: Work in pairs and try to arrange the following events in chronological order – based on the true events in Borneo.• Rats brought plague• Lizards ate roaches (with DDT)• Cats died• Caterpillar numbers went up• WHO (World Health

Organization) sent DDT to Borneo

• Mosquitoes were wiped out• Caterpillars ate grass roofs• Cats were parachuted in

• Cats caught lizards containing DDT

• Roaches stored DDT in their bodies

• Grass roofs collapse• Lizards disappeared• Lizards slowed down• Rats increased• People Suffered from

Malaria

The Story:In the 1950's, the Dayak people of Borneo tragically

suffered an outbreak of malaria, spread by mosquitoes. The World Health Organization (WHO), without thinking through all the consequences, sprayed the area with DDT to kill the mosquitoes. The mosquitoes died, malaria lessened and the people of Borneo were happy.

But then grass roofs on the villagers houses started to collapse. It appeared that a parasitic wasp had previously been keeping a thatch-eating caterpillar under control and the DDT killed the wasps, meaning the caterpillars were free to eat as much as they wanted!

As if their houses falling in on them wasn’t enough – insects that had been poisoned by DDT were eaten by gecko lizards, which were then eaten by cats. The cats started to die from the poison, rats began to flourish, and the people were threatened by outbreaks of 2 NEW serious diseases: plague & typhus.

WHO initiated Operation Cat Drop and the cats started parachuting. The people of Borneo gained new feline friends, the rat population declined and the people of Borneo were happy once more. The End.

The moral of the story:As Rachel Wynberg & Christine Jardine, Biotechnology and

Biodiversity - Key Policy Issues for South Africa, 2000 said:

"This is a graphic illustration of the interconnectedness of life, and of the fact that the root of problems often stems from their purported solutions."

Source: www.flycatfly.com/Parachuting_Cats.html

Correct order of events• Borneo suffered from Malaria• WHO (World Health Organization) sent DDT to Borneo• Mosquitoes were wiped out• Caterpillar numbers went up• Caterpillars ate grass roofs• Grass roofs collapse• Roaches stored DDT in their bodies• Lizards ate roaches (with DDT)• Lizards slowed down• Cats caught lizards containing DDT • Lizards disappeared• Cats died• Rats increased• Rats brought plague• Cats were parachuted in

Pesticides in the USA

• Around 25,000 Pesticides products• 25% used for homes, parks, pools and golf courses

• According to EPA- the average lawn in the U.S. is doused with 10x

more synthetic pesticides per acre than U.S. cropland

- 84% of U.S. homes use pesticide products such as bait boxes, pest strips, bug bombs, flea collars, and pesticide pet shampoo and weed killers for lawns and gardens

- Each year, more than 25,000 people in the U.S., because of household pesticide use, became ill, accidentally poisoned & or died (mostly children under age 5.)

Pesticides in the USA• Broad vs. Narrow Pesticides:

• Broad Spectrum Agents are toxic to many species

• Selective/Narrow Spectrum are specific to a certain species

• Pesticides vary in their persistence (how long they remain in the environment)

The Case for Pesticides1. “Benefits outweigh the potential harmful effects.”

- Save Human lives by protecting against diseases like malaria, typhus and sleeping sickness.

- Prevent premature deaths of at least 7 million people from insect-transmitted diseases

Pesticides Sprayed on Dallas

• http://abcnews.go.com/GMA/video/pesticides-sprayed-dallas-combat-mosquitoes-17033025

The Case for Pesticides

• They increase food supply and decrease food cost

- According to UN Food & Agriculture Organization

35% of food supply is lost to pest before harvest and 20% after harvest.

-37% of the potential U.S. food supply= 13% from insects, 12% to plant pathogens, 12% to weeds.

The Case for Pesticides

3. Increased Profit to farmers:

- for every $1 spent on pesticides leads to an increase in U.S. cope yields worth $4.

- if the data for what pesticides are used on the crops is include the profit is only $2.

The Case for Pesticides

4. They work faster and better than the alternatives:

- Control most pests quickly & at a reasonable cost

- have long shelf life

- are easily shipped and applied

- are safe when handled properly

- If genetic resistance occurs, farmers can use stronger doses or switch to other pesticides

The Case for Pesticides

5. Relatively Safe

American Council on Science & Health (ACSH)

- Health risks are insignificant when used properly

- Today’s pesticides are actually safer than those of the past

- Many of the new pesticides are used at a lower rate than in the past

Microbiologist, Bruce Ames states:

- consume more natural pesticides produced by plants than synthetic ones

- risk of getting cancer from natural & synthetic pesticides is small

- exposure to natural pesticides in food causes more cancers than exposure to synthetic

The Case Against Pesticides

The Case Against Pesticides

1. Can cause Genetic Resistence- Organisms reproduce rapidly and can develop a

resistance in 5-10 years- Surviving organisms come back stronger- Leads to pesticide treadmill

http://www.youtube.com/watch?v=2J-boNjH_HA

http://www.youtube.com/watch?v=iIcfafBmbv4

The Case Against Pesticides

2. Broad Spectrum insecticides kill natural predators

- 1/3 of the most destructive pests are secondary pests that became widespread after the use of insecticides.

- the natural predator of the secondary pests were wiped out

Fig. 20.4, p. 507

600

500

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300

200

100

01950 1960 1970 1980 1990 2000 2010

Year

Nu

mb

er o

f sp

ecie

s

Boll weevilGypsy moth cateripllar

Insects and mites

Weeds

Plant diseases

RISE OF GENETIC RESISTANCE TO PESTICIDES RISE OF GENETIC RESISTANCE TO PESTICIDES 1945-981945-98

The Case Against Pesticides3. Pesticides Do Not Stay Put

- Less than 2% of the pesticides used actually reach the target pest

- Less than 5% of herbicide reaches the appropriate weeds

- Pesticides may end up in the air, water, bottom sediments, food or non-target organisms

http://www.youtube.com/watch?v=gjly5ykM9kQ

The Case Against Pesticides

4. Some pesticides harm wildlife

According to USDA & U.S. Fish & Wildlife Service, pesticides applied to cropland in the U.S.- each year

- wipe out more than 20% of honeybee colonies costing farmers $200 million in lost pollination

- kills 67 million birds

- kills 6-14 million fish

- hurt 20% of endangered species

Chemical Whales

• http://www.abc.net.au/catalyst/stories/2395723.htm

The Case Against Pesticides

5. Threat to Human Health

According to the WHO & UN Environment Program (UNEP)

- 3 million agricultural workers are seriously poisoned by pesticides each year

- 18,000 deaths (probably under estimated)

- 165 of the approved active ingredients are carcinogenic

- Exposure in food is related to 4,000-20,000 cases of cancer/year

- Birth defects, genetic mutations, nervous system disorders, immune system problems

Case for Sarah Carter

• http://www.3news.co.nz/Thailand-deaths-Evidence-Sarah-Carter-killed-by-insecticide/tabid/423/articleID/210265/Default.aspx

Bhopal, India, 2-3 Dec. 1984On the night of 2-3 December 1984, a sudden release of about 30 tonnes of methyl isocyanate (MIC) occurred at the Union Carbide pesticide plant at Bhopal, India. The accident was a result of poor safety management practices, poor early warning systems, and the lack of community preparedness. The accident led to the death of over 2,800 people living in the vicinity and caused respiratory damage and eye damage to over 20,000 others. At least 200,000 people fled Bhopal during the week after the accident. Estimates of the damage vary widely between US $350 million to as high as US $3 billion.

http://www.youtube.com/watch?v=HXDOzMRrKlo

Pesticide Regulation in the US

• All commercial pesticides require EPA approval for general and/or restricted use.

• Federal Insecticide, Fungicide and Rodentcide Act (FIFRA) - Pesticides are evaluated for

biological active ingredients & their affects

- If approved, the EPA sets acceptable tolerance levels

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

Pesticide Regulation in the US

• EPA requires Label and signal words- Danger & Poison (PELIGRO)

-Skull & cross bones-Highly Toxic

-Danger- No Skull/Cross Bones-Significant Skin or Eye effects

-WARNING/AVISO-Moderately toxic

- Caution-Slightly Toxic or relatively non-toxic

Good & Bad News About Pesticides

• Good News:• Between 1972-2000, EPA banned or restricted 56

active pesticide ingredients in U.S. • EPA asked to reevaluate 600 pre-1972 active

ingredients used in pesticides. • Bad News:

• As of 2008 less than 10% of the pesticide evaluations have been completed

• Weak Enforcement• Weak laws for pre 1972 toxins

Other Disturbing Facts

• Many active ingredients are known to be carcinogens

• Missouri study showed increased childhood brain cancer with use of various pesticides

• Swedish report showed exposure to glyphosate (key agen in Round-Up) tripled chances of getting non-Hodgkin’s lymphoma

• http://www.cbsnews.com/video/watch/?id=6491394n

The Circle of Poison

• Senator Patrick Leahy of Vermont has three times now introduced a bill to Congress which he calls "Circle of Poison". This bill is meant to combat the unhealthy trade going on between the U.S. and other nations in terms of pesticides.

-U.S. companies can make and export banned chemicals to other countries

-26 tons per day-Many of the crops the pesticides are used on return to the

USA

-Bob Lake, director of policy at the FDA's Center for Food Safety and Applied Nutrition, says that the FDA does find illegal amounts of pesticide residues in 1-2% of domestic produce, and up to 5% of imported produce.

http://abcnews.go.com/WNT/video/pesticides-orange-juice-government-officials-say-affected-safe-for-sale-health-15510176

How to Improve Pesticide Regulations

1. Need to make human health the primary consideration for setting pesticide limits

2. New tests for evaluating toxicity of pesticides

3. Consider the cumulative exposure of all Pesticides

How to Improve Presticides1. Kill only target species

2. Harm no other species

3. Break down into something harmless after doing its job

4. Not cause genetic resistance in target organisms

5. Be more cost effective than doing nothing

Other Ways to Control Pests

1. Excessive Pesticide Use:

One of the biggest problems with the use of pesticides is in

determining the Economic Threshold- The point where economic damage due to the

pest outweighs the cost of the pesticide. - Takes careful monitoring of fields to assess crop

damage- Need to determine pest population by using traps

baited with chemicals that attract the key pests.

Other Ways to Control Pests

• Many Farmers don’t want to deal with finding the Economic Threshold

- To protect themselves, farmers often practice Insurance Spraying and/or Cosmetic Spraying.

- They spray more pesticides to help yield a better crop. - Buy insurance that pays them if their crops die from Pests- Use more pesticides so their crops look better because consumers only buy best looking fruit and vegetables

Other Ways to Control Pests

2. Cultivation Practices:

- crop rotation

- changing planting times

- planting trap crops

- increasing habitat for natural predators

3. Create Genetically Resistant Plants or Genetically Modified Foods (GMO’s)

GMO’s

• Plant DNA is altered by giving it a virus, using radiation, or done by adding one or more genes to a plant's genome using genetic engineering techniques.

• Typically, genetically modified foods are transgenic plant products: soybean, corn, canola, and cotton seed oil. These may have been engineered for faster growth, resistance to pathogens, production of extra nutrients, or any other beneficial purpose

• http://www.cbsnews.com/video/watch/?id=50134502n

Other Ways to Control Pests4. Biological Pest Control:

Pro’s Con’s- Focus on target -no mass reproduction- Are non toxic -slow- Save money - must be protected from

spraying- Minimize resistance - can become a pest

Other Ways to Control Pests

5. Insect Birth Control-Males are sterilized using radiation and then introduced into a population to unsuccessfully mate with females.- Sterilization of insects

- used with screwworms and fruit flies

-Disadvantages include…-high cost-estimating mating times/behaviors-need large # of males- males must be reintroduced