environmental science: toward a sustainable future richard t. wright pests and pest control ppt by...
TRANSCRIPT
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