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Identification, Symptoms and nature of Damage: Termites
Introduction
Termites are polymorphic social insects
and live in large communities in above
ground earthen mound called
termitarium or in subterranean
galleries. Termite nest is very intricate
network of galleries and sub- and sub-
sub galleries. Termites cause damage
to crops, trees, timber, furniture, books
and other materials in subtropical and
tropical environments. In general,
rainfed crops are infested more than
irrigated ones.
Termite termitariaCourtesy: www.savethekimberley.com
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Identification
In India, termites belonging to
families Macrotermitidae,
Microtermitidae and
Odontotermitidae are main termite
species. Macrotermes are mound
building species while Odontotermes
make galleries underground and on
trees. On the other hand,
microtermes build perforated
underground nest.
Four castes of termites are
structurally and functionally distinct
forms.Termite queenCourtesy: Entomology Division, IARI, New Delhi
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Termite castes
A. Primary reproductives: These have two
pairs of large membranous wings, which
are shed after they have swarmed in the
process of founding new colonies.
Swarming takes place during evening
hours after pre-monsoon showers.
Primary reproductives are adapted for
short aerial life after which they form
queen and king of colony. King and queen
live in royal chamber, several feet below
soil surface. Queen is several inches long
and functions as a egg laying machine.
Queen may live for 15-50 years. Termite
colonies may harbour over a million
individuals derived from single pair of
queen and king.
Swarming adults
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B. Supplementary reproductives:
Members of this caste have no aerial
life. These are not normally found in
colonies headed by original king and
queen. They appear after a lapse of
several weeks if one or both of king
or queen die.
C. Workers: Workers are numerically
the most important members of the
community. Usually pale in colour,
they look more like nymphs than
adults of other castes. The head is
directed downwards. Termites, which
we generally see in field or in
household are workers.
Termite workers
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Duties of workers
They take no part in reproduction on
defence of colony. However, all duties
practically devolve upon the members of
this caste.
They exhibit marked care for eggs and
young ones and in times of danger remove
them to safe places.
They also feed and tend queen, forage
for food and in fungus growing species,
cultivate fungus gardens.
In subterranean species, the workers
excavate galleries and tunnels that serve
as nest. In mound building species, they
construct termitarium and repair damage
to it. It is the workers that destroy crops,
timber, wood-work and other materials.
Tree damaged by termites
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D. Soldiers
Soldiers constitute the most specialized
members of the community. These can
be readily recognized by strongly
sclerotized heads. They are specialized
for defence of the colony. They protect
colony from ants and other vertebrate
predators. The typical soldier attacks
with its mandibles, which pierce and
slice.
Soldier
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Damage
Termites greatly damage crops
and trees in subtropical and
tropical environments. In
general, rainfed crops are
infested more than irrigated ones
especially debilitated by stress
such as drought or irregular
rainfall. Damage to crops or
structures is done by workers.
They damage the crop from
sowing to harvesting. Termites
feed on underground plant parts
such as roots and stems.
Termite galleries at soil surface
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As a result, plants get
detached from their base and
dry up. Infested plants can be
easily pulled out. Soil also gets
filled in stems of damaged
plants.
Crops such as groundnut,
sugarcane, sorghum, bajra,
maize, arhar, wheat, gram,
and fruit and forest trees
suffer heavy termite damage.
TermitariaCourtesy: http://farm3.static.flickr.com
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Cultural and mechanical methods in termite management
Undertake deep summer ploughing to destroy
termite galleries.
Destroy termitaria and fill exposed holes with
water.
Kill queen through nest excavation.
Dispose off crop residues.
Apply only rotten FYM and never use fresh FYM.
Use wood ash in nursery and around tree bases.
Adopt appropriate intercropping. Maize and beans
intercropped together suffer less from
termites.
Maintain crops in sound health through balanced
fertilizer applications. Unstressed
crops are less damaged.
Cover inter-row space with vegetative matter to
divert termites from crop plants.
Summer ploughing & flooding
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Let’s sum upTermites are polymorphic social insects and live in large communitiesin above ground earthen mound called termitarium or in subterranean galleries.
Four castes of termites are structurally and functionally distinct forms.
Queen may live for 15-50 years. Termite colonies may harbour over a million individuals derived from single pair of queen and king.
Soldiers constitute the most specialized members of the community. These can be readily recognized by strongly sclerotized heads. They are specialized for defence of the colony.
Workers are numerically the most important members of the community. All duties of the colony except reproduction practically devolve upon the members of this caste.
Termites greatly damage crops and trees in subtropical and tropical environments. They feed on underground plant parts such as roots and stems.
Deep summer ploughing, queen killing, clean cultivation, use of rotten FYM, mulching and irrigation etc. help to reduce termite incidence.
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