Insect pests are those insect species that are injurious or a
nuisance. They cause injury or damage to crops in the field and grains
in storage. Man and his domesticated animals are also attacked by insect
pests. Arthropod predators belong to the phylum Arthropoda and are most
times beneficial in the control of insect pests. Arthropod predators
are members of the phylum Arthropoda which capture and feed on the prey.
They are generally larger than their prey and kill or consume many prey
during their life time. Examples of arthropod predators include the
lady beetles, spiders, praying mantids, damsel bugs, lace wings, syrphid
flies etc. They can feed on insect pests like aphids, moths, mites,
butterflies, brown plant hoppers etc. These arthropod predators have
been very effective in some cases of biological control programes of
insect pests. Examples include the use of the cocinellid beetle, Radolia cardinalis (a lady bird beetle) to control the cottony-cushion scale, Icerya purchasi (a
scale insect) which was a citrus pest in carlifornia, U.S.A. also wolf
spiders have been effectively used to control the rice pest (the brown
plant hoppers) in Indonesia.
Arthropod species occur from below the soil surface to the
tree canopy. However, only a small fraction are observed on a frequent
basis because many are microscopic or hidden below ground or plant
tissue. Very few species are classified as pest. Whether they feed on
plants or plant produce invade our homes, inflict painful bites or
stings. Infect most insects and other arthropods are beneficial and
serve a variety of important functions in the garden. The abundance of
beneficial insects especially predators is often limited in urban
landscapes because these environments typically are characterized by
disturbance. Disturbance factors include use of pesticides and other
chemicals, air pollution and wind-borne dust, all of which may increase
mortality of beneficial arthropods. Residential landscapes often lack
adequate amounts of essential resources such as food, nesting sites and
shelter than enhance reproduction and survival of natural enemies. Some
common strategies are employed to conserve them in residential
landscapes and these strategies may help reduce insecticide use and
improve plant health by enhancing natural control of arthropod pests.
Because many arthropod pests are exotic the aim of classical
biological control is to reduce pest numbers by reuniting old enemies
through importation of predators from the area of insect pest origin.
Lady beetles, green lace wings and spiders are familiar examples of
predator arthropods inhibiting residential landscapes and gardens. In
general, predators are larger than their prey, consume many prey items
during their life time and feed on a broad range of species immature
and/or adults may be predatory and often do not leave behind any
evidence of attack.
However, these arthropod predators often help to keep aphids,
spider mites, caterpillars and other insect pests under control.