Biological Control Flashcards
What is biological control?
any non chemical control
what are some examples/types of biological control? (in general)
- sterilized male
- natural control
- mating disruption
- classical biological control
- microbial control
How does the release of sterile males work as a biological control?
sterile males are released –> females mate with sterile males and do not become fertilized –> no offspring
How are sterile males produced?
males are reared in large numbers and radiated enough to sterilize but not kill
In what species has sterilization of males been successful?
- screw worm
- codling moth
What is required for sterilization of males to work?
- assumes males still able to mate
- high ratio of sterile to fertile
- limited geographic distribution of bugs (small areas)
- LOTS of funding = increased taxes
What does sterilization of males work best on?
flies but has been tried on moths (codling moth)
How does mating distribution work?
- identify pheromone used by insect
- synthesize + set out pheromone so males cant find real females due to large amount of pheromone
- females do not get mated and dont produce offspring
- population declines
Pros of mating distribution?
- specific to one type of pest and can be very effective
- compatible with other controls
- no toxins
- no resistance to the method
Mating distribution works well on what?
moths
What is natural control?
building up natural enemies in an area
- dont use pesticides
- provide other food sources (eg: hedge rows)
What insects are used as natural controls?
- lacewings
- ground beetles
- spiders
- parasitic wasp
- minute pirate bug
predatory mites
What is inundative control?
rear natural enemies in lab and release in field or greenhouse
What is a problem with inundative natural control?
intraguild predation
What is intraguild predation?
predators may prey on each other and reduce successful control
What is required to minimize intraguild predation?
- systems balanced with different interactions possible
- lab + field studies
- must understand ecological relationships between bugs
What is biological control?
foreign species is introduced and their population rises dramatically. Introduce another foreign species (their natural predators) in order to reduce + stabilize their populations
What is an example of the use of biological control? (Problem insect? Introduced insect? Result?)
Problem: cottony cushion scale - Introduced: vedalia beetle (ladybug-like) Result: saved citrus industry
What are the risks of classical biocontrol?
- hard to predict what introduced species are going to feed on (eg: predator may out-compete native species or prefer to feed on other species than intended)
What are the steps of biological control?
- is the invasive species an ecological or economical problem?
- is there sufficient support to initiate a biological control program?
- find out basic biology (eg: identify weed properly, literature search etc)
- Look for possible agents
- Test host plants (look for feeding, egg laying and development
- Introduce if everything checks out
What can biological control work on?
- introduced insect species
- introduced plant species
What is an example of a plant being controlled by biological control? How was it solved?
Knapweed -introduced:
- gall flies which fed on seeds
- Beetle which fed on roots
- larinus minutus
What is microbial control?
use of insect diseases to control pests
Pros of using microbial control?
- more specific than chemicals
- reduced nontraget casualties
- effective
What does bacillus thurigiensis effect?
- lepidoptera
- coleoptera
- Mosquitos
What are sme advantages of nucleopolyhedrovirus?
- specific to host
- can be used in underdeveloped countries
