Integrated Pest Management Strategy:
Biological Control
What is Biological Control?
• Biological control is defined as the reduction of pest populations by natural enemies and
typically involves an active human role.
• According to Professor Harry Scott Smith, the “Father of Modern Biological Control”, it
is the use of natural enemies to control insect pest.
• Biological control is the management of a pest, typically invasive species, by introducing
natural predator into the environment
History of Biological Control
• Term biological pest control first used by Henry Scott Smith at the 1919 meeting of the
American Association of Economic Entomologist at California.
• Biological control started to emerge in 1870 in U.S.A.
• First international shipment of an insect as a biological control agent was made by
Charles V. Riley in 1873. shipping to France the predatory mites to help fight grape vines
disease agent Phylloxera
• The first importation of the parasitoid into U.S.A. was of Contrsia glomerata from
Europe to control Cabbage white butterfly.
Natural Enemy or Biological Control Agent
These are parasitism, predation and other mechanisms for controlling plant pest. They
play an important role in controlling the plant pests like nematodes, weeds, parasitic
nematodes, and mites. The biological control agent helps in maintaining and balancing
the plant species along with their natural enemies
Predators
Predators are mainly free-living species that directly consume a large number
of prey during their whole lifetime. Given that many major crop pests are insects, many
of the predators used in biological control are insectivorous species.
Parasitoids
Parasitoids lay their eggs on or in the body of an insect host, which is then used as a food
for developing larvae. The host is ultimately killed. Most
insect parasitoids are wasps or flies, and many have a very narrow host range.
Pathogens
Pathogenic micro-organisms include bacteria, fungi, and viruses. They kill or debilitate
their host and are relatively host-specific. Various microbial insect diseases occur
naturally, but may also be used as biological pesticides. When naturally occurring, these
outbreaks are density-dependent in that they generally only occur as insect populations
become denser.
Types of Pathogens
Fungi - cause disease in insects, include at least 14 species that attack aphids.
Bacteria - used for biological control infect insects via their digestive tracts, so they offer
only limited options for controlling insects with sucking mouth parts such as aphids and
scale insects.
Virus - are specific to individual insect host species and have been shown to be useful in
biological pest control.
Oomycota - Oomycota or oomycetes form a distinct phylogenetic lineage of fungus-like
eukaryotic microorganisms. They are filamentous, heterotrophic, and can reproduce both
sexually and asexually.
Biological control may be divided into three (3) areas of implementation:
1. Importation / Classical Biological Control
2. Conservation
3. Augmentation
Importation / Classical Biological Control
It is the introduction of specialist natural enemies from the homeland of a pest of foreign
origin. The objective is to establish populations of these natural enemies to attack the pest
and to reduce its numbers.
Augmentation
Augmentation biological control basically means adding natural enemies, either where
they are not present , or are they present but in small numbers.
It has been used more extensively in agro or forest ecosystem, but there are examples of
successful use in nearly all settings.
Advantages and Disadvantages of Biological Control
Advantages Disadvantages
Specific to a particular pest Can sometimes fail in its specificity
Self-sustaining system It is a slow process
Cheap after start-up Expensive at start-up
It works most of the time Doesn’t completely destroy a pest
