文档介绍：BIOLOGY Activity Book ONE,
Chapter 5, ecosystem
- Suggested answer,
with reference to a published
source OUP, and much modified.
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Biological pest control
Questions
1 Oecophylla smaragdina and insect pests
The concept of predation is applied in this example. The predators Oecophylla smaragdina (no need to remember) are used to eat up the insect preys.
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Biological pest control
2 Trichogramma ostriniae and corn borers
The concept of parasitism is applied in this example. The parasites Trichogramma larvae stay inside and feed on the host eggs of corn borers.
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Biological pest control
Task 2
Biological pest control is the use of natural enemies 天敵 to decrease the pest population, or keep it from reaching a high level.
What is biological pest control ?
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Biological pest control
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Task 2
1 As the biological control agents are natural enemies that have already existed in nature, they have less impacts on the environment and water quality. (To be continued.)
ANS:
What are the advantages over chemical pesticides?
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Biological pest control
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The natural enemies are often very specific for a particular pest. Therefore other non-targeted plants, animals and humans are unaffected by their use.
Biological pest control can be more economical than the use of some chemical pesticides.
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Biological pest control
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Major kind
The way they work
Example
Predators
The predators prey on and therefore remove the pests.
Ladybird beetles that feed on aphids and mites.
What biological control agents are available?
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Biological pest control
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Major kind
The way they work
Example
Parasites
The larvae of the parasites develop on or within the host pests, and kill the hosts as they mature.
Flies that lay an egg into the body of ants
What biological control agents are available?
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Biological pest control
Major kind
The way they work
Exam