biological control

1. Approaches in Biological Control
(Augmentive)
• Release of large numbers of biological control agent
to supplement the small numbers already present,
in expectation of a greatly increased effect.
Example: A beneficial wasp is naturally present but
is killing only 10% of the stink bug eggs. Release of
many more of the same wasp species, reared in an
insectary, results in many more stink bug eggs
being killed.

2. Approaches in Biological Control
(Classical /Inoculative)
• Importation and release of biological control agents
into an area in which they are not already present,
with intent to establish a permanent population.
• Example: After determining that the weevil attacks only
the aquatic weed, USDA breed the weevil in a laboratory
and release a few hundred at many places in the
southern USA. The weevil eats the weed and
reproduces, and its populations grow and spread to still
other places where the weed is causing problems. After
a year or two, the weed and the weevil still exist at many
places, but both at low numbers, and the weed is no
longer a problem

3. Approaches in Biological Control
(Inundative)
• Importation and release of biological control agents
into an area in which they are not already present,
with intent to establish a permanent population.
• Example: After determining that the weevil attacks only
the aquatic weed, USDA breed the weevil in a laboratory
and release a few hundred at many places in the
southern USA. The weevil eats the weed and
reproduces, and its populations grow and spread to still
other places where the weed is causing problems. After
a year or two, the weed and the weevil still exist at many
places, but both at low numbers, and the weed is no
longer a problem

4. Approaches in Biological Control
(Manipulative)
• The manipulation of elements in the environment
to enhance the numbers and/or actions of natural
enemies. Example: Channels are dug in a saltmarsh
to connect pools of water. This allows naturally-
occurring predatory fish to gain access to pools and
eat mosquito larvae.
• Conservation Biological Control is a subset of this
because it seeks merely to conserve. Example: Plots of a
particular weed are left untreated with herbicide around
a sugarcane field. This conserves the wasp population,
reduces the pest (scarab) population, and reduces
damage to the sugarcane.

5. Arthropod natural enemies
(Predators)
• Diverse and efficient predators
• Great impact on insect populations
• Lack of feeding specificity
• Many predators are polyphagous
• Unsuitable for targeting particular pest species
• Spiders and Predatory insects (Odonata, assassin bugs,
robber flies, etc)
• Lady Beetles, Green Lacewings, Syrphid Flies, Predatory
Bugs, Ground Beetles, Mantids, Hunting Wasps,
Predatory Mites