Environmental Science: Toward a Sustainable Future Richard T. Wright Pests and Pest Control PPT by Clark E. Adams Chapter 16.

Environmental Science: Toward a Sustainable Future Richard T. Wright

Pests and Pest Control

PPT by Clark E. Adams

Chapter 16

Pests and Pest Control

The need for pest control Promises and problems of the chemical

approach Alternative pest control methods Socioeconomic issues in pest

management Pesticides and policy

Formosan Subterranean Termite Invades the French Quarter

The Need for Pest Control

Any organism that has a negative effect on human health or economics

Any organism that is noxious, destructive, or troublesome Plants or animals (see Fig. 16-2)

Formosan termite Fire ants Aedes mosquito Medfly

Pest Control Purposes

Protect our food Protect our health Convenience

Pesticide Use in the United States

Philosophies of Pest Control

Chemical technology Use of chemicals to kill large numbers of the

pest Short-term protection Environmental and health consequences

Philosophies of Pest Control

Ecological pest management Control based on pest life cycle and ecology Control agent may be an organism or

chemical (more on next slide)

Philosophies of Pest Control

Specific to pest and/or to manipulate a part of the ecosystem

Emphasizes protection from pest

Promises and Problems of the Chemical Approach

Development of chemical pesticides and their successes

Problems stemming from chemical pesticide use

Development of Chemical Pesticides

First-generation pesticides (inorganic) First attempt at chemical technology Toxic to humans and agricultural plants Pests developed resistance

Development of Chemical Pesticides

Second-generation pesticides Used after WW II Organic chemical Toxic to humans and agricultural plants Pests developed resistance

The DDT Story

DDT: the magic bullet Extremely toxic to insects; seemed nontoxic to

humans and other mammals Cheap Broad-spectrum and persistent (more next

slide)

The DDT Story

DDT: the magic bullet Effective for disease prevention (typhus fever,

malaria) Expanded agricultural production Paul Müller awarded Nobel prize in 1948

Aerial Spraying

Problems Stemming from Chemical Pesticide Use Development of resistance by pests Resurgences and secondary pest

outbreaks Adverse environmental and human health

effects

Resistance

Chemical pesticides lose effectiveness Resistant pest populations produce next

generations

Genetics of Pest Resistance

RR x rrNonresistant x resistant

Rnonresistant gene

R

rresistant gene

Rrnonresistant offspring

Rr

r Rr Rr

Genetics of Pest Resistance

Rr x RrHeterozygous nonresistant x nonresistant

R r

R RRdies

Rrdies

r Rrdies

rrSURVIVES!

Pesticide Resistance

Resurgence and Secondary Outbreaks

Resurgences: after “eliminating” a pest, its population rebounds in even higher numbers than previous levels.

Secondary outbreaks: outbreaks of species’ populations that were not previously at pest levels.

The Bugs Are Coming!

Time Magazine, July 12, 1976, page 38

The Pesticide Treadmill

Human Health Effects

Cancer, dermatitis, neurological disorder, birth defects, sterility, endocrine system disruption, immune system depression.

Agricultural workers suffer acute poisoning during pesticide application.

Human Health Effects

Aerial spraying and dumping bring pesticides in contact with families and children.

Soldiers exposed to agent orange in Vietnam suffered high rates of cancer and other diseases.

Environmental Effects

DDT led to the decline in populations of several bird species Bald eagle Peregrine falcon

Bioaccumulation Biomagnification

Biomagnification

Nonpersistent Pesticides

Substitutes for banned pesticides Break down after a few weeks Can still be harmful because of:

Toxicity Dosage Location

Alternative Pest Control Methods

Cultural control Control by natural enemies Genetic control Natural chemical control

Complex Life Cycle of Insects

Cultural Control

Genetic Control

Plants or animals are bred to be resistant to the attack of pests. Chemical barriers Physical barriers

Genetic Control

Introduction of genes into crops from other species: transgenic crops.

Sterile males are released into pest population.

Control UsingNatural Enemies

Natural Chemical Control

A volatile chemical produced by the opposite sex of a species which alters the reproductive behavior of the opposite sex. Perfumes Colognes After shave Natural body odors

Natural Chemical Control

Manipulation of pests’ hormones or pheromones to disrupt the life cycle

Japanese beetle trap (see Fig. 16-18)

Socioeconomic Issues of Pest Management

Pressures to use pesticides

Integrated pest management

Organically grown food

The Economic Threshold

Integrated Pest Management (IPM)

An approach to controlling pest populations using all suitable methods—chemical and ecological—in a way that brings about long-term management of pest populations and also has minimal environmental impact

Pesticides and Policy

Fifra: Federal Insecticide, Fungicide, and Rodenticide Act

FQPA of 1996: Food Quality Protection Act Pesticides in developing countries

FIFRA or FQPA?

Pesticides evaluated on intended use and potential effects to human health and the environment

Training and protection of agricultural workers

Protection of public from risks of pesticides used on food

End of Chapter 16