Topic 5 - Pest management Flashcards
What is a pest?
An organism that interferes with human activity
Situation- and opinion-dependent definition
What are 3 natural controls?
Predators, parasites, disease
What % do natural enemies control the populations of potential pest species?
98%
What is one of the worst enemies of an insect?
A spider
What are pesticides?
Chemicals designed to kill pest organisms
Insectides kill..
One or more species of insect
Herbicides kill..
One or more species of herbs/plants
Fungicides kill..
One or more species of fungus
Rodenticides kill..
One or more species of rodents (mice, rats)
Biocides kill..
Species other than the target
Do plants make their own pesticides?
Yes, for millennia
What are the first-generation pesticides?
Sulphur, lead, arsenic, mercury
Non-degradable inorganic toxins
What are second-generation pesticides?
Synthetic organic compounds
What was the first second-generation pesticide?
DDT
Persistent - not readily degraded
Water insoluble, retained on crops
Fat soluble
1939 Paul Muller discovered it was a potent insecticide
What is bioaccumulation?
The storage of chemicals in an organism in higher concentrations than are normally found in the environment
What is biomagnification?
The build-up of chemical elements or substances in organisms in successively higher trophic levels
Why was DDT banned?
Banned in 1972 due to adverse environmental effects (wildlife), as well as potential human health risks
What is DDT still used for in some countries?
To combat malaria
Who was the author of Silent Spring (1962), a book about the environmental impacts of pesticide use?
Rachel Carlson
What are the benefits of pesticides?
Save human lives from pest-transmitted disease
Increase food supplies
Increase profits for farmers
Work faster and better than alternatives
Health risks low vs. benefits with proper use
Newer pesticides becoming safer and more effective
What is the ideal pesticide?
Affects only target pests
Does not allow pests to evolve immunity
Rapid breakdown to harmless byproducts after use
Affordable and cost-effective
What is a promising pesticide?
Plant-based chemicals
Which tree contains a variety of chemicals with specific properties for combating insect pests in different ways?
Neem trees
What are the major problems with using pesticides?
- Promotes evolution of genetic resistance by selecting members of population with genetic immunity (especially a concern for species that reproduce quickly, e.g. boll weevil)
- Wipes out natural predators (creates new pest species, increases populations of existing pests)
- Migrate into the natural environment
- Harm to other wildlife or human health