Mosquitoes are found worldwide and transmit many diseases. They have three body parts - head, thorax, and abdomen. The female mosquito feeds on blood which it needs for egg production, while males feed on plant juices. Mosquitoes undergo complete metamorphosis from egg to larva to pupa to adult. The larvae live in water and the adult mosquito lives around 2 weeks. Different genera of mosquitoes transmit different diseases depending on their habitat and biting behaviors. Integrated control methods include eliminating breeding sites, using larvicides, biological controls, indoor residual sprays, and protective measures.

1. Mosquito
Phylum: Arthropoda
Class: Insecta
Order: Diapter
Family: Culicidae
Genera: Anopheles, Aedes, Culex, Mansonia
Mosquitoes constitute the most important single family of insects, constituting public health importance by
transmission of diseases. They are found all over the world, the four important groups of mosquitoes commonly
known for transmission of diseases are Anopheles, Aedes, Culex and Mansonia.
Morphology:
The body is divided into 3 distinct parts namely head thorax and abdomen.
Head:
It is a semi-globular structure
comprising of:-
(i) A pair of compound
eyes
(ii) The proboscis (needle
like structure inside
which are hidden
delicate mouth parts
with which mosquito
bites),
(iii) A pair of palpi (on
either side of the
proboscis)
(iv) A pair of antennae or
feelers .
The mouth parts are well
developed in female mosquitoes
thus they feed on human and
animal blood, whereas male
mosquitoes survive on plant
juices.
Thorax:
The thorax is large and rounded
in appearance and bears :-
(i) A pair of wings dorsally
(ii) Three pairs of legs
ventrally.
Abdomen :
The abdomen is long and
narrow and is composed of 10
segments, the last two of which
are modified to form the
external genitalia (Clasper in
male mosquito and Cerci in
female mosquito).

2. Life history:
Mosquito undergoes complete metamorphosis consisting of four stages as follows:
(1) Egg: Eggs are laid on the surface of water, 100-250 at a time. This stage lasts for 1-2 days.
(2) Larva: The larva is a free swimming creature with an elongated body divisible into head, thorax and
abdomen, it is also voracious feeder. Larva passes through four stages of growth called "instars" with moulting
between each stage. This stage remains for 5- 7 days. Depending on the species of larvae, it may or may not
have siphon tube (respiratory tube).
(3) Pupa : The pupa is comma-shaped in appearance, with a large rounded cephalothorax and a narrow
abdomen. It represents the resting stage in the life history of the mosquito; it does not feed and prefers to stay
quiet at the water surface. Two small respiratory tubes or trumpets project from the upper surface of the thorax.
The pupal stage lasts for 1- 2 days.
(4) Adult: When the development is complete, the pupal skin splits along the back and the adult mosquito or
imago emerges. It rests for a while on the pupal skin to allow its wings to expand and harden and then flies
away. Normally the adult mosquito lives for about 2 weeks. The males are generally short-lived.
Under favourable conditions of temperature and food supply the life cycle from the egg to adult is complete in
7- 10 days.
Diagram of life cycle of mosquito:

3. Species Specific Details:
Anopheles mosquito:
 These are widly distributed species.
 Some of the species known are: An. Culicifacies (rural area), An. Fluuiatilis (hilly regions), An.
Minimus, An. Philippinensis, An. Stephensi (urban area), An. Sundaicus and An. Leucosphyrus.
 It breeds in clean water.
 The Anopheles lays her eggs singly; the eggs are boat-shaped and possess lateral floats.
 The larva of the Anopheles floats horizontally in the water, and palmate hair are present on abdominal
segment.
 Adults rest inclined at an angle to surface.
 Some diseases transmitted are: malaria, filaria (not in India)

4. Culex mosquito:
 Also known as nuisance mosquitoes.
 Important species known is culex fatigans.
 It breeds in dirty water collections, eg: stagnant drains, cesspools, septic tanks, burrow pits, etc
 The Culex lays her eggs in small clusters or rafts; the eggs do not possess lateral floats.
 The Culicine (e.g. , Culex, Aedes, and Mansonia) larvae, are suspended in water with their heads
downwards; they possess a siphon tube, which is situated on the 8th abdominal segment.
 Some diseases transmitted are: Bancroftian filariasis, Japanese encephalitis, West Nile fever, Viral
arthritis (epidemic/polyarthrilis)

5. Aedes mosquito:
 Also called as ‘tiger mosquito’ due to its characteristic black body with white stripes.
 Important species are : Aedes aegypti, Aedes vittatus and Aedes albopictus.
 It breeds in artificial accumulations of water in and around human dwellings.
 The Aedes lays her eggs singly; the eggs are cigar shaped.
 The Culicine (e.g. , Culex, Aedes, and Mansonia) larvae are suspended in water with their heads
downwards; they possess a siphon tube, which is situated on the 8th abdominal segment.
 Some diseases transmitted are: Yellow fever (not in India), Dengue, Dengue haemorrhagic fever,
Chikungunya fever, Chikungunya haemorrhagic fever, Rift valley fever.

6. Mansonia mosquito:
 These are big, black or brown mosquitoes with speckling on their wings and legs.
 The common Indian species are : M.annulifera, M. uniformis, M. indiana and M. longipalpis.
 They breed in ponds and lakes containing certain aquatic plants, especially the floating types like Pistia
stratiotes and water hyacinth.
 The Monsonio lays her eggs in star-shaped clusters attached to the undersurface of the leaves of certain
aquatic plants, notably the pisita plant.
 The larvae of the Monsonio are attached to the rootlets of certain aquatic plants by their siphon tubes;
they obtain air from the plant rootlets.
 Pupae come to the surface of water and the fully formed adults emerge and escape.
 Some diseases transmitted are: Malayan (Brugian) filariasis, Chikungunya fever.

7. Bionomics:
The study of the habit and habitats of mosquito is called bionomics. It provides effective ways of controlling the
mosquitoes.
Habits Anopheles Culex Aedes Mansonia
Feed on Anthropophilic
and zoophilic
Anthropophilic Anthropophilic Anthropophilic
Biting time Evening or early
part of night
Midnight Day biters Night
Resting place Indoor rester –
cattle sheds and
human dwellings
Outdoors Dark and quit
places,
bedrooms,
kitchen
Outdoors
Breeding place Clean water,
ponds, pools,
lakes, Spring,
overhead tanks
Dirty water
collections,
stagnant drains
Cesspools
Septic tanks
Burrow pits
Artificial
accumulation of
water, tyres,
Broken glasses
Aquatic plants
Flight 0.75-1 km 11 km <100 m -
Diseases
transmitted
malaria, filaria (not
in India)
Bancroftian
filariasis, Japanese
encephalitis, West
Nile fever, Viral
arthritis (epidemic/
polyarthrilis)
Yellow fever (not
in India), Dengue,
Chikungunya fever,
Rift valley fever.
Malayan (Brugian)
filariasis,
Chikungunya fever
Control
measures
Indoor residual
spraying,
Biological
control
measures.
Environmental
control
measures,
outdoor
spraying.
Prevent artificial
collection of
water.
Biological
control
measures, de-
weeding aquatic
plants.
Hibernation: They remain dormant/ hibernate when environmental conditions are unfavorable.
This is usually seen in winter.
Life span: It is influenced by temperature, humidity and other climatic factors. Extremes of
temperature are fatal and life span varies between 8 and 34 days. Males are usually short lived.

8. Mosquito control measures:
Integrated approach is the recommended method for mosquito control.
Classification:
1 Anti-Larval Measures
(a) Environmental control
(b) Chemical control
(c) Biological control.
2 Anti -Adult Measures
(a) Residual sprays
(b) Space sprays
(c) Genetic control.
3 Protection Against Mosquito
Bites
(a) Mosquito net
(b) Screening
(c) Repellents.
Antilarval measures:
a) Environmental control:
The main purpose is to eliminate their breeding places (source reduction), and comprises minor engineering
methods. It requires understanding of bionomics of mosquito, as strategies vary according to species of
mosquitoes.
for example ,
For Culex mosquitoes- there should be abolition of domestic and peridomestic sources of breeding such as
cesspools and open ditches; and arrangements should be made for adequate collection, removal and disposal
of sewage and waste water.
For Aedes mosquitoes- the environment should be cleaned up and water holding containers such as
discarded tins, empty pots, broken bottles , coconut shells should be discarded.
For Anopheles mosquitoes- their breeding places should be looked for and destroyed by appropriate
engineering measures such as filling up cracks and crevices and application of proper drainage system.
For Mansonia mosquitoes- the aquatic plants should be removed or destroyed by herbicides.
Source reduction methods generally produce results that are permanent.
b) Chemical control:
Commonly used larvicides are mineral oils, paris green and synthetic insecticides.
Mineral oils:
Diesel oil, kerosene, special oils.
Mechanism of action: When applied on water, oil spreads and forms a thin film, which cuts off the air
supply to the mosquito larvae and pupae. Oil probably has also has specific toxic action on insect stages.
Dosage: 40 to 90 litres per hectare. Once a week on all breeding places.
Disadvantages: renders water unfit for drinking; it kills fish.
Paris green (copper acetoarsenite):
Emerald green , micro-crystalline powder practically insoluble in water.
Mechanism of action: Paris green is a stomach poison and to be effective it must be ingested by the larvae.
Dosage: 2 per cent dust (2 kg of paris green and 98 kg of a diluent such as soapstone powder or slaked lime
in a "rotary mixer") or 1 kg of actual paris green per hectare of water surface.
Advantages: In the dosage applied, paris green does not harm fish , man or domestic animals.
Synthetic insecticides : eg: Fenthion, Chlorpyrifos , and Abate.
Mechanism of action: These organophosphorous compounds hydrolyze quickly in water.

9. Dosage: Abate- 56-112 g/ha; malathion- 224-674 g/ha; fenthion- 22-112 g/ha; chloropyrifos- 11-16 g/ha,
has been found to be a very effective larvicidal agents, and also the least toxic. The organochlorine
compounds (e.g. , DDT, HCH) are not recommended for larviciding operations because of their long
residual effect, water contamination and increased risk of developing resistance in the vector mosquitoes.
c) Biological control: a wide range of fishes like Gambusia affinis and Lebister reticulatus feed readily on
mosquito larvae.
Antiadult measures:
a) Residual sprays: Spraying of houses with residual insecticides like DDT, Lindane, Malathion, etc in
recommended doses can kill the resting and hidden mosquitoes. Once applied, it remains effective for 3-12
months depending on chemical used. However, prolonged usage can cause resistance among mosquitoes.
b) Space sprays: insecticidal formulation is sprayed into the atmosphere in the form of a mist or fog to kill
insects. The common space sprays are :
(i) Pyrethrum extract : The active principle (pyrethrin) is a nerve poison and kills insects instantly
on mere contact. Sprayed at a dosage of 1 oz of the spray solution per 1,000 C.ft. of space.
Pyrethrum sprays are effective in reducing the number of mosquitoes temporarily since it has no
residual action.
(ii) Residual Insecticides : New equipment has been developed for ultra low volume space spraying.
The most extensively used insecticides are malathion and fenitrothion for ULV fogging.
c) Genetic control: sterile male technique, cytoplasmic incompatibility, chromosomal translocations, sex
distortion, and gene replacement. They are advantageous over chemical methods, being cheaper and
potentially more efficient and above all it does not cause vector resistance.
Protection against mosquito bite:
a) Mosquito net: insecticide treated bed nets are available. The size of the openings in the net is of utmost
importance - the size should not exceed 0.0475 inch in any diameter. The number of holes in one square
inch is usually 150.
b) Screening: Screening of buildings with copper or bronze gauze having 16 meshes to the inch is
recommended. The aperture should not be larger than 0 .0475 inch. Screening of buildings is costly, but
gives excellent results.
c) Repellents: various formulations are available, it can be burnt, the fumes of which are toxic to adult
mosquito or just apllied over linens. Some can also be used fr topical application. Diethyltoluamide (deet)
has been found to remain active against C. fatigans for 18- 20 hours. There are others also like indalone,
dimethyl phthalate, dimethyl carbate, ethyl hexanediol, etc. Repellents or culicifuges are used mainly for
application on the skin.