Insect repellents are divided into two types based on their source and chemical composition. 1. natural insect repellent 2. synthetic insect repellent.

2. INTRODUCTION:
•INSECTS ARE CRUCIAL COMPONENT OF OUR ECOSYSTEM.
•DIRECT PESTS ATTACK THE BODY OF THE HOST ORGANISMS. INDIRECT PESTS ARE
MOSTLY CONCERNED WITH THE TRANSMISSION OF PATHOGENS.
•INSECT REPELLENTS DISCOURAGES INSECTS FROM LANDING OR CLIMBING ON THAT
SURFACE AND PREVENT AND CONTROL THE OUTBREAK OF INSECT BORNE DISEASES.
•DIFFERENT INSECT REPELLENTS HAVE DIFFERENT REPELLENCY TIME.

3. WHAT ARE INSECT REPELLENTS?
An insect repellent is a
natural or synthetic
chemical substance.
deters insects from
approaching or settling.
Most repellents are not
meant to kill the insects but
to keep them away to prevent
bites and send them flying or
crawling away.
Insect repellents must be
volatile.

4. WHY INSECTS ARE ATTRACTED TOWARDS US?
mosquitoes are commonly
attracted towards CO2 which
we exhale.
1-octen-3-ol is released as
an odorant and is present in
human breath and sweat
and is thought to attract
biting insects.
sometimes called
mushroom alcohol.

5. COMMON INSECTS REPELLENTS:
•INSECT REPELLENTS MAY BE CATEGORIZED AS:
•NATURAL INSECT REPELLENTS INCLUDE:
1. ESSENTIAL OIL OF LEMON EUCALYPTUS 2.PYRETHRINS FROM CHRYSANTHEMUM CINERARIAEFOLIUM
3. CITRONELLA OIL 4. CATNIP OIL 5. LEMON GRASS 6. LAVENDER 7. NEEM OIL 8. CEDAR OIL ETC.
•SYNTHETIC INSECT REPELLENTS INCLUDE:
1. DEET (N,N-DIETHYL-M-TOLUAMIDE) 2. PERMETHRIN 3. IR3535 4. METHYL ANTHRANILATE
5. ICARIDIN 6. METOFLUTHRIN 7. BENZALDEHYDE FOR BEES 8. DIMETHYL CARBATE

6. DEET (N,N-DIETHYL-METATOLUAMIDE)
Oldest and most widely used synthetic repellent.
The US department of agriculture discoveredit during the World War 2.
DEET blocks the olfactory receptors of the insect that perceive attractants in human breath and sweat.
As a consequence the insect does not recognize the potential host as an attractive prey.
Mostly used in the form of sprays, lotions creams.
For a product of 100% concentration repellence time is reportedup to 12 hours.
Maximum allowed concentration in different countries is 30%. And then it shows the repellency time of 4-6 hours.

7. PERMITHRIN:
Permethrin - discovered
in 1973, is on the World
Health Organization's List
of Essential Medicines,
the safest and the most
effective medicine
needed in health system.
It is an aromatic
compound. Having the
molecular formula of
C21H20Cl2O3.
it is light yellow, semi-
solid compound and is
only applied to clothing,
never be applied directly
to skin.
Permethrin acts as a
stomach poison when
ingested by insects.
kills adults, eggs, and
larvae, and has a slight
repellent effect
against insects.
As it is applied on clothes
so it remains effected
even after repeated
laundering.
Generally repellence
time is noted up to 6
hours.

8. ICARIDIN:
• ICARIDIN ALSO CALLED AS PICARIDIN OR HEPIDANIN, SEEMS TO BE AS EFFECTIVE AS DEET WITHOUT THE
INCONVENIENCE OF BEING AN ORGANIC SOLVENT.
• PIRCARIDIN IS ODORLESS HAS A PLEASANT FEEL AND DOES NOT DAMAGE CERTAIN FABRICS.
• AS DEET IT CAN BE APPLIED ON INFANTS AS YOUNG AS 2 MONTHS.
• FUNCTIONS TO REDUCE THE VOLATILITY OF THE ODORANTS (1-OCTEN-3-OL).
• ICARIDIN "MASK" THE ABILITY OF VOLATILE ODORANTS ON THE SKIN TO ACTIVATE OLFACTORY NEURONS
AND ATTRACT MOSQUITOES.
• ACCORDING TO THE CONSUMERS REPORT, RESET IN 2006 15% SOLUTION IS GOOD FOR ABOUT ONE HOUR
AGAINST AEDES AND 4.8 HOURS AGAINST CULEX. IF USED IN HIGH CONCENTRATIONS IT CAN REPEL
MOSQUITOES UP TO 8 HOURS.

9. NATURAL INSECTS REPELLENTS:
1. PYRETHRINS:
• NATURAL PYRETHRINS ARE A MIXTURE OF SIX CHEMICALS THAT ARE TOXIC TO INSECTS EXTRACTED
FROM VARIOUS PLANTS (E.G. CHRYSANTHEMUM CINERARIAEFOLIUM)
• STRUCTURALLY RELATED TO ESTERS WITH A CYCLOPROPANE CORE.
• NATURAL BROAD-SPECTRUM CONTACT INSECTICIDES WITH A FAST KNOCKDOWN, BUT WITH
ONLY SHORT RESIDUAL EFFECT. SOMETIMES ACT AS CARCINOGENIC.
• PYRETHRINS EXCITE THE NERVOUS SYSTEM OF INSECTS THAT TOUCH OR EAT IT AND LEADS TO
PARALYSIS AND ULTIMATELY THEIR DEATH.
• HALF-LIVES ARE 11.8 HOURS IN WATER AND 12.9 HOURS ON SOIL SURFACES.

10. CITRONELLA OIL:
Oil of citronella is distilled
from two grass varieties i.e.
citrus plants Cymbopogon.
It contains an aldehydic
active ingredient known as
Citronellal or Rhodinal
Another research shows that
citronellal has strong
antifungal qualities.
It works by masking scents
that are attractive to insects.
application of 100% citronella
can provide complete
protection against three
types of mosquitoes up to 120
minutes in laboratory
settings.
The repellency of citronella oil
decreasedover time, from
97.9% at 0h to 71.4% at 1h.

11. NEPETALACTONE: (CATNIP):
Catnip is a member of the mint family, it contains a chemical called nepetalactone.
It is a more effective spatial repellant than DEET,it is not as effective as a repellent when used on the
skin.
Like DEET, it blocks the olfactory receptors of the insects that perceive attractants in human breath and
sweat but only to some extent.
Research has showing that it repels mosquitoes for about 2-4 hours.

12. ARE INSECT REPPELENTS SAFE FOR CHILDERN?
• IF A PERSISTENT AND CONSIDERABLE AMOUNT OF INSECT REPELLENT ENTERS IN OUR BODY IT MAY
PROVE TOXIC TO US.
• DEET CAN CAUSE SHORT-TERM EYE OR SKIN IRRITATION PEOPLE HAVE REPORTED SKIN AND EYE
IRRITATION FROM PICARIDIN. ETC.
• FEW TIPS ARE GIVEN FROM EPA AND PROFESSIONAL ORGANIZATIONS REGARDING CHILDREN AS UNDER:
1. THE AMERICAN ACADEMY OF PEDIATRICS (AAP) DOES NOT RECOMMEND INSECT REPELLENTS FOR
CHILDREN YOUNGER THAN TWO MONTHS.
2. OIL OF LEMON EUCALYPTUS PRODUCTS SHOULD ONLY BE USED ON CHILDREN OLDER THAN THREE YEARS.
3. THE AAP RECOMMENDS THAT PRODUCTS APPLIED TO CHILDREN SHOULD NOT HAVE MORE THAN 30%
DEET.

13. RULES TO FOLLOW WHEN USING REPELLENTS:
•APPLY REPELLENT SPARINGLY ONLY TO EXPOSED SKIN. USE REPELLENTS ON SKIN UNDER
CLOTHING ONLY WHEN MOSQUITOES CAN PIERCE THROUGH THE CLOTHING.
•DO NOT INHALE OR INGEST REPELLENTS OR GET THEM INTO THE EYES.
•AVOID APPLYING HIGH-CONCENTRATION PRODUCTS (MORE THAN 50% DEET) TO THE
SKIN.
•PREGNANT AND NURSING WOMEN SHOULD MINIMIZE USE OF REPELLENTS.
•NEVER USE REPELLENTS ON WOUNDS OR IRRITATED SKIN.
•IF A SUSPECTED REACTION TO INSECT REPELLENTS OCCURS, WASH TREATED SKIN, AND
CALL A PHYSICIAN.

14. SUGESIONS AND CONCLUSION:
Synthetic insect
repellents are more
effective .
Repellents must not
be used in higher
concentrations.
Use nets made up of
fiber ---environment
friendly.
There is a build in
defense mechanism
against mosquitoes--
-1-Methylpiperazine.