Dr. O.P. Chaudhary
( Prof. of entomology)
*Losses of stored food grain by diff. agencies in
India is 9.33%.
*In other developing countries losses may extent up
to 30 to 50%.
*The agencies that responsible for losses are:-
4) Micro organisms
5) Moisture etc.
A) Preventive measures:
B) Curative measures:
A) Preventive measures:
1. Hygiene and sanitation:
*Many factors responsible for food grain losses in storage can be
minimised by maintaining hygiene and sanitation.
*Before storing ensure that food grain must be dry(8-10 %) , clean ,
cool , wholesome , free from obnoxious odour.
*Storage structure should neat and clean and air tight.
There are diff. sanitation measures which can be
a) Threshing floor should be clean, free from insect
infestation, away from vicinity of village.
b) Harvesting machines, threshing machines and means of
transport should be cleaned before use.
c) Cleaning of storage structures, receptacles and godowns
*Removing dirt, rubbish, webbing etc.
*Closing of cracks, crevics, holes, walls
*Closing of rat burrow with broken glass
pieces and mud.
*White washing the storage structure.
d) Bags used for storage should be treated with insecticide or
2. Proper stacking:
*Stack bags properly on dunnage (wood/plastic) 0.5
metre away from wall and floor in the lines keeping
0.5 metre between two lines and 0.2 metre open
space towards the roof.
*Don’t stack more than 10 bags vertically.
3. Disinfestation of storage containers, structures
*Clean and disinfest empty used gunny bags by
dipping in boiled water and drying under sun.
*Treat gunny bags by dipping in cypermethrin 0.01%
or fenvalerate 0.01% or malathion 0.1% for 10
minutes and dry.
*Treat walls and surfaces by malathion(50 EC) or
fenitrothion(50EC) using any of insecticide in one
litre of water .
*Fumigate with aluminium phosphide @ 21-30 gram.
*There are diff. curative measures :-
9. Other methods
1. Ecological measures:
Safety of stored grain from pest depends upon:-
a) Storage temp.
b) Grain moisture content
c) Available of oxygen
a) Storage temperature:-
* Temp.range 25-35°C increase insects development.
* Temp. above 40°C and blow 15°C retards reproduction
and development of insects.
* Temp. above 45°c and below 10°c kills the insects.
b) Grain moisture content:
* 10% moisture content escapes grains from insects.
* 12-16% moisture content increase seed deterioration.
c) Availability of oxygen:
* Reduction in oxygen level stops multiplication of
* Oxygen can be reduced by adding CO2 and N2.
2. Mechanical measures:
These are diff. practicable mechanical measures:-
* Screening or sieving out reduces insects attack by
removing broken and cracked grains.
* Screenings should be destroyed immediately.
* Bags used for carrying screenings should not used again
b) Grain protection devices:
* TNAU Insect Probe Trap
* TNAU Pitfall Trap
* Indicator Devices
* UV Light Trap for Grain Storage Godown.
3. Physical control measures:
a) Heat treatment:
Most of insects die at 55-60 C within 10-20 minutes. It can be
achieved by infra red heaters.
b) Controlled atmosphere:
*CA can be achieved by-
*Adding gaseous or solid CO2 (9-10%)
*Adding N2 gas
*Removing O2 gas(2-4%)
*Allowing metabolic processes which remove O2 or add CO2.
c) Mixing of inert dust:
Some inert dusts desiccate cuticle of insects.
Efficacy depends upon:-
*Particle size- finer particles, higher insecticidal efficacy.
*Particle shape and form- hard crystalline and angular substance
*Humidity- efficacy of dust decreases at 70% or more RH.
d) Solar energy:-
Since Ancient time in India
* 1st practised in Australia by exposing grains for at least 3 times
at temp.60-66° C in 1922.
* Mookherjee et al.(1968) observed elimination of C. maculatus in
moong, pea and gram by solar heat at temp.45-55° C.
*Dortbudak (1975) reported exposing container of lentil and black
gram infested with C. chinensis to sunshine for 4 hours(9:00-
13:00) inhibit the rate of pest multiplication and reduce grain
*Heating at 45° C completely prevents the hatching of one day old
larvae in Rhizopertha dominica.
4. Cultural control measures:-
a) Splitting of pulses:
Store pulses after splitting because some insects like pulse
beetle C. chinensis prefer whole grains not broken.
b) Parboiling of paddy:
Parboiled rice is least susceptible to insect attack as compared
to raw rice because of hard glutenized outer layer.
5. Botanical control measures:-
*Plants having toxicity against insect pests- Neem, Karanj,
Undi, Castor, Lemon grass, mustard, coconut, sesame,
groundnut, Aak, Datura etc.
*Jacob and Sheila(1990)- Neem oil @ 1ml/100 g seeds
caused 100% mortality of adult beetles of C. chinensis.
*Castor oil @ 1ml/100 g in seeds of cowpea inhibits the
oviposition(26.6 eggs/female) as against 79.4 eggs/female
in untreated seeds.
*Castor oil @ 1ml/100 g seeds decrease egg viability.
6. Chemical control measures:-
*Most popular and most effective.
*Malathion 50 EC spray over bags in ratio 1:100 @ 3 l/100 m².
*Deltamethrin 2.5 WP @ 3 mg a.i./m².
*Fumigation with ethylene dichloride and carban
tetrachloride @ 1 l for 20 quintals of grains or 30 l/ 100 m³
of space with exposure period of 4 days.
*Aluminium phosphide @ one tablet(3 g) per metric tonnes or
25 tablets/100m³ of space with exposure period of 7 days.
Parasites Attacking stage Insect pest
Larva R. dominica,
Callosobrunchus spp., S.
Antrocephalus mahensis Larva Corcyra cephalonica
Pteromalus cerealellae Larva Sitotroga cerealella
Trichogramma cacoeciae Eggs S. cerealella, C.
Predators Attacking stage Insect pest
Acarophenax sp. Eggs Dermestes sp.
Cheyletus sp. Egg & young larva R. dominica
Pyemotes ventricosus Eggs Trogoderma granarium,
8. Engineering control measures:
*Air-tight storage- food grains kept in air tight sealed
structure remains insect free because grains and insects
respires and release CO2.
*Hermetic storage-underground storage of paddy in Eastern