Pests Plagues

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Pests Plagues PoliticsLecture 14

• Biological Control
• Controlling Pest Insects
• Lets Go Green

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• Key points
• Biological Control
• Describe two key arthropod classes of biocontrol
  agents
• What are the constraints of biological control
• What are the advantages of biocontrol
• Give other non-insect biocontrol agents

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The biggest enemy of an insect is another INSECT!!
Bio-control is the use of a pest insects natural
insect enemies for its control.
Bugs eat Bugs
1) As direct predators
2) As parasites parasitoids
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Predators Ladybird adult
Both are excellent predators
Ladybird larva
Photos Ken Gray photo collection, OSU
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Asian weaver ant One of the earliest known
insects as biocontrol agents
http//en.wikipedia.org/wiki/Weaver_ant
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Mike Burgett
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Parasitoids A fly parasitoid larva emerging
from the host larva.
Predation A true bug, lunching on another true
bug.
Photos Ken Gray photo collection, OSU
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Polyembryony has taken placeand the bee larva
containsmany thousands of wasp larva
A carpenter bee giving you the once-over
A carpenter bee larva that has been parasitized
by a wasp.
Mike Burgett
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Mike Burgett
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Biological Control Advantages

• Self-perpetuating
• Pest specific
• Density dependent
• Cost effective
• Environmentally compatible

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Biological Control Constraints

• Not immediately effective (may take years)
• Not eradicative (is this really a constraint?)
• Biocontrol agents unknown for many pest species.
• Doesnt always work
• Historically only one out of four attempts has
  been successful

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What makes an effective biocontrol agent??

• High to complete prey specificity
• Multivoltine with respect to target species
• Well adapted to habitat of target species
• Excellent searching ability

Lacewing immature at lunch
Photos Ken Gray photo collection, OSU
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Classic Biological Control Control of an Exotic
insect pest by the
introduction of its natural enemies

• foreign exploration
• quarantine processing
• mass propagation
• field colonization (release)
• evaluation of impact
• 100 successes in the past 100 years!!

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Bugs on plants
Tyria jacobaeae, Cinnabar moth
http//en.wikipedia.org/wiki/Cinnabar_moth
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Preventing predation and enhancing biocontrol
Tansy ragwort flea beetle. Prevents plants from
flowering through feeding. Introduced in USA in
1969
Bright colors of larvae/adults warning sign
http//en.wikipedia.org/wiki/Cinnabar_moth
http//ucce.ucdavis.edu/files/repositoryfiles/ca24
04p12-63742.pdf
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In addition to Classic Biocontrol (bug vs. bug),
we also use

• Insect Pathogens
• Viruses - Japanese Beetle Milky Disease,
  Nuclear Polyhedrosis Virus
• Bacteria - the classic Bacillus thuringiensis
• Microsporidians - against grasshoppers
• Entomopathogenic fungi
• Entomopathogenic nematodes

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Japanese beetle
Bacillus popilae
http//www.biconet.com/biocontrol/bpopillae.html
http//www.hort.uconn.edu/ipm/homegrnd/htms/wgrbpi
cs.htm
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I dont feel so good.
Moth larva infected with a Polyhedrosis virus
http//www.monarchlab.org/lab/research/topics/Enem
ies/Default.aspx
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• Key points on Biological Control
• Describe two key arthropod classes of biocontrol
  agents
• What are the constraints of biological control
• What are the advantages of biocontrol
• Give other non-insect biocontrol agents

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Another true bug munching on an aphid. - A
direct predator.
Bye
A mule killer - a wingless parasitoid wasp -
also known as velvet ants.
Photos Ken Gray photo collection, OSU
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• Key points
• Biological Control
• Describe two key arthropod classes of biocontrol
  agents
• What are the constraints of biological control
• What are the advantages of biocontrol
• Give other non-insect biocontrol agents