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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