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ENSC 1005 Lecture Notes - Biological Agent, Resistance 3, Rodenticide

Child and Family Studies
Course Code
ENSC 1005
Heather Kaye

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Monday March 4, 2013
Pest Management
Pest- any species that is undesirable or a nuisance
- In natural ecosystems natural enemies (predators, parasites, and disease organisms)
control the population of most of the potential pest species -> nature’s checks and
Pesticides- chemicals used to kill or control populations of organisms we consider
Types: Insecticides- kills undesirable insects
Herbicides- kills undesirable weeds
Fungicides- kills undesirable fungi
Nematocides- kills undesirable roundworms
Rodenticides- kills undesirable rodents
- Naturally occurring chemicals in plants are produced to repel or kill herbivores that feed
on plants (ex: dieffenbachia, milkweed, poinsettia, cocoa plant)
First Generation Pesticides- natural chemicals usually taken from plants
Examples: Basil- repels mosquitoes and flies
Cayenne pepper repels ants
Spiders repel cockroaches, spruce budworm, gypsy moths, aphids
Second Generation Pesticides synthetic (manmade) organic chemicals
- DDT (1939) was the first second generation pesticide
- See table 23.1 p. 553 for others
Benefits: 1) Save lives from insect transmitted disease (i.e. malaria, bubonic
plague, typhus
2) Increase food supplies 55% of world’s potential human food supply
is lost to pests using pesticides reduces this loss
3) Increase profits for farmers more crops for sale -> more money
4) Work faster and better than alternatives
5) When used properly, health risks low compared with benefits
6) Newer pesticides are safer and more effective than older pesticides
uses natural substances or organisms
7) New pesticides used at lower rates per unit area compared to older
Problems: 1) Speeds up development of genetic resistance in pests
2) Some kill natural predators and parasites may have kept another
unknown pest in check but when killed by pesticide, unknown pest
now becomes a new known pest
3) Do not stay put washed into waterways, carried by air, and make
their way up the food chain through biomagnifications
4) Persistence can remain in environment for years
5) Many pesticides are highly toxic to wildlife and humans
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