The Pesticide Dilemma Chapter 23. What is a Pesticide? First-Generation Pesticides Inorganic compounds (e.g., lead, mercury) Botanicals (e.g., nicotine,

The Pesticide Dilemma

Chapter 23

What is a Pesticide?

First-Generation Pesticides

• Inorganic compounds (e.g., lead, mercury)

• Botanicals (e.g., nicotine, pyrethrin)

Pyrethrin is used against mosquitos

Nicotine has been banned as pesticide since 2001

Pyrethrin is derived from chrysanthemum flowers.

http://www.thegardenhelper.com/pixpg/chrysettiapix.html


Second-Generation Pesticides

• Synthetic botanicals (e.g., pyrethroids)

• DDT


The Major Groups of Insecticides• Chlorinated hydrocarbon (e.g., DDT)

• Organophosphates (e.g., malathion) The chemicals in this class kill insects by disrupting their brains and nervous systems. Unfortunately, these chemicals also can harm the brains and nervous systems of animals and humans

• Carbamates (e.g., carbaryl)

SHORT-TERM HEALTH HAZARDS- The carbamate pesticides listed above are highly poisonous chemicals, with the exception of carbaryl(SEVIN), which is moderately poisonous.- All these chemicals can be absorbed through the skin, especially through cuts and scratches, so direct contactshould be avoided.- Carbamates are highly irritating to the eyes.LONG-TERM HEALTH HAZARDS- Carbamates are generally not considered to be cancerous, with two exceptions. Carbaryl (SEVIN) andcarbofuran (FURADAN) can mix with other elements in the stomach to form possible cancerous chemicals.- Some carbamates, such as carbofuran (FURADAN), have been shown to cause birth defects or reproductionproblems in laboratory animals. Further studies are required for specific compounds.- Carbamates do not accumulate and persist in the body.


The Major Kinds of Herbicides

• Selective herbicides

(e.g., 2,4-D – kills broad-leaved plants)

• Nonselective herbicides

(e.g., glyphosate, aka: Round-UpTM)

http://www.scotts.com/smg/brand/roundup/game/roundup_game.html



Benefits and Problems with Pesticides

Benefit: Disease Control

Location of malaria


Benefit: Crop production

Farmers save ~$3 - $5 in crops for every $1 invested into pesticides

Mo money, mo money, mo money!!!


Problem: Evolution of Genetic Resistance

# of species exhibiting genetic resistance to pesticides



Creates a pesticide treadmill

Pesticide application

Kills most pests

Resistant survive

Numbers increase

New population genetically resistant

EVEN MORE

INCREASE



Resistance Management• Create a “refuge” (no pesticide applied)

• Avoid repeated use of same pesticide


Problem: Imbalances in the Ecosystem

California red scale was introduced into California between 1868 and 1875, apparently on citrus seedlings from Australia. The scale insect is native to Southeast Asia but has been transported on citrus seedlings to all arid and semiarid regions of the world where citrus is grown. It occurs in all of California's citrus growing areas.


Problem: Imbalances in the Ecosystem

Creation of New Pests


Problem: Persistence, Bioaccumulation, and Biological Magnification

Biomagnification of DDT


Problem: Mobility in the Environment

Risks of Pesticides to Human Health

Short-term Effects of Pesticides

Handling of food with pesticide residue

There are two types of exposure: chronic and acute, like me!!!

Move over Bowles, that’s my line!!!


Short-term Effects of Pesticides

Case-in-Point: The Bhopal Disaster• 40 tons of methyl isocyanate gas

released

• 600,000 people exposed

• 2,500 immediately killed

• 2,500 more killed through time

• 50,000-60,000 have serious health problems


Long-term Effects of Pesticides

• Potentially higher risk of cancer

• Sterility

• Miscarriage / birth defects

• Potentially higher risk for Parkinson’s disease

Alternatives to Pesticides

Using Cultivation Methods to Control Pests

• Interplant mixtures of plants

• Strip cutting

• Planting, fertilizing, and irrigating at proper time

• Crop rotation


• Biological ControlsUsing naturally occurring diseases, parasites, or predators to control a pest

• Pheromones and HormonesUse pheromones to attract insects to trapsSynthetic hormones induce abnormal development

• Reproductive ControlsSterile-male technique – inundate pest population with large numbers of sterile males


Genetic Controls

Using Genetically Modified plants (GMOs)

Case-in-Point: Bt, Its Potential and Problems

Genetically modified corn to produce Bt toxin

Potential problem: may affect non-target species, such as monarch butterfly

Quarantine


Integrated Pest Management


Integrated Pest Management

Rice Production in Indonesia

IPM introduced


Irradiating Foods

Predominantly used on meats

Kills many microorganisms

This really makes Zombies! No listen to me, they will take over the world, they already live in the oceans!!!

Laws Controlling Pesticide Use

Food, Drug, and Cosmetics Act (1938)

Pesticide Chemicals Amendment (1954)

Delaney Cause (1958)

Federal Insecticide, Fungicide, and Rodenticide Act (1947)

Estimates of Risk of Cancer from Pesticide Residue

Laws Controlling Pesticide Use

Food, Drug, and Cosmetics Act (1938)

Pesticide Chemicals Amendment (1954)

Delaney Cause (1958)

Federal Insecticide, Fungicide, and Rodenticide Act (1947)

Food Quality Protection Act (1996)

The Manufacture and Use of Banned Pesticides

Some US companies still make banned or seriously restricted pesticides and export the product.

This can potentially lead to the importation of food tainted with banned pesticides

Soylent Green is People!

The Manufacture and Use of Banned Pesticides

The Global Ban of Persistent Organic Pollutants

Documents

The Pesticide Dilemma Chapter 23. What is a Pesticide? First-Generation Pesticides Inorganic compounds (e.g., lead, mercury) Botanicals (e.g., nicotine,