materi kuliah biokontrol

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Definition and Scope of Biological Control

2. PltH107BiologicalControlFl2005
Biological ControlBiological Control
Control of pests by disrupting theirControl of pests by disrupting their
ecological status, as through the use ofecological status, as through the use of
organisms that are natural predators,organisms that are natural predators,
parasites, or pathogens. Examples ofparasites, or pathogens. Examples of
biocontrol include the use of ladybugs tobiocontrol include the use of ladybugs to
prey on aphids and scale insects and theprey on aphids and scale insects and the
treatment of turf with spores of thetreatment of turf with spores of the
bacterium bacterium Bacillus popilliaeBacillus popilliae, which cause, which cause
milky disease in Japanese beetle larvae.milky disease in Japanese beetle larvae.

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Biological control = the action of
parasites, predators or pathogens
in maintaining another organism’s
population density at a lower
average than would occur in their
absence

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Applied biological control as “the
manipulation of natural enemies by man
to control pests”
Natural biological control as that “control
that occurs without man’s intervention”

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Advantages of Biological Control:
• high level of control at low cost
• self-perpetuating at little cost after initial
effort
• very few harmful effects on man,
environment etc
• some NE’s reproduce rapidly
• some NE’s search out hosts
• some NE’s survive even at low host
densities

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Types of Biological Control:
Classical - involves importation and
establishment of new natural enemies to an
area, usually for exotic pests, occasionally for
natives
Conservation - enhance conditions for existing
natural enemy survival and reproduction
Augmentation - involves rearing and release of
natural enemies to supplement what is there or
when permanent establishment is not possible

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Origins of Pests:
Indigenous (native) - organisms in a
specified area that evolved in that location
Adventive (exotic) - organisms in a
specified area that did not evolve there, but
arrived from somewhere else

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Targets and Agents of Biological Control

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Targets of biological control:
Insects have been most common target:
• worldwide apprx 550 sp
•homopterans have been most successful target
(due to scale, aphid and whitefly)

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Targets of biological control (cont’d):
Several families of Mites have been targets, including:
Snails are the next most common invertebrate target
• either herbivorous sp. that attack crops or
• medically important sp. that are intermediate hosts for
human or domestic animal pathogens

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Agents of biological control:
Parasitoids have been the most common type of
natural enemy introduced for control of insects
• most parasitoids used are in the order
Hymenoptera and to a lesser Diptera

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Agents of biological control (cont’d):
Predators are important control agents of both native
and introduced pests
There are 32 families that are significant for pest
suppression, of these most common in crops are:
• ground beetles
• lady beetles
• green lacewings
• ants

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Agents of biological control (predators cont’d):
Spiders
Fish (Gambusia affinis) have been used through augmentative
releases for the control of mosquito larvae

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Agents of biological control (cont’d):
Pathogens and nematodes attacking arthropods:
• These may be important natural sources of
mortality for many species
• some have been commercially formulated and
marketed as insecticides
These include:
• bacteria (esp. genus Bacillus)
• viruses (esp. Baculoviridea)
• fungi (esp. Entomophthoraceae)
• protozoa (including microsporidians)
• nematodes (esp Steinernematidae and
Heterorhabditidae)

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