Crop Protection - Grain Storage

By TamilNadu Agricultural University on 03 Jan 2019 | read

Grain Storage :: Importance


  • In India annual storage losses have been estimated14 -million tones of food grain worth of Rs. 7,000 crore every year in which insects alone account for nearly Rs. 1,300 crores.
  • According to World Bank Report (1999), post-harvest losses in India amount to 12 to 16 million metric tons of food grains each year, an amount that the World Bank stipulates could feed one-third of India's poor.
  • TNAU has been estimated the losses to food grains in the farmers holdings in Tamil Nadu 12.9 per cent in paddy 16.0 per cent in sorghum14.0per cent in bajra12.7 per cent in maize.
  • Out of these post-harvest losses storage alone 6.58 per cent, in that -insects alone account for 2.0 to 4.2 per cent followed by rodent’s 2.50per cent, Birds 0.85 per cent and moisture 0.68 per cent. 

Types of storage losses 
Insects cause different kinds of losses viz.,

  • Quantitative loss
  • Qualitative loss
  • Loss of seed viability
  • Damage to storage structures 

Quantitative loss

  • Direct feeding insects cause loss in weight of the stored grains
  • A rice weevil will eat 14 mg out of 20 mg of a rice kernel during its developmental period.
  • But commercially the whole grain is lost
  • A female weevil, through three generations per year, has the biotic potential to reproduce 1,500,000 offspring which will consume 1,500,000 kernel of rice (amounting 30 kg of rice)
  • A gravid female of Sitotroga cerealella can destroy 50 g of rice completely in 3 generations

 Image title

Qualitative loss

  • Direct feeding on the grain
  • Chemical changes in grain content
  • Contamination of grains with moult skin and body parts
  • Spreading the pathogenic micro-organisms
  • Loss of seed viability
  • Insects were found to cause the loss of viability of seeds to an extent of 3.6 to 41 % in paddy

Damage to storage structures

  • Insects like Lesser grain borer has the capability to destroy the wooden storage structures, containers polythene lined bags etc.,
  • Food losses -Direct or Indirect losses:
  • A direct loss is disappearance of food by spillage, or consumption by organisms including insects.
  • An indirect loss is the lowering of quality to the point where people refuse to eat it.

Insect trap

  • No granaries in the earth can be filled with grains without insects. The harvested produce contains egg (or) larvae (or) pupae in them because of field carryover infestation which cannot be avoided in developing countries like India.
  • Hence, timely detection of the stored grain insects will help to prevent heavy losses. TNAU is one of the pioneering institutes in India in the development of detection devices for stored grain insects.
  • These devices exploit the wandering behaviour of the insects and help in timely detection of insects in stored produce leading to timely control. These include viz,
  • TNAU insect probe trap.
  • TNAU Pitfall trap
  • TNAU Two-in-one trap for pulse beetle
  • Indicator Device
  • Automatic insect removal bin.
  • UV – Light trap for warehouse
  • TNAU Stored grain insect pest management kit

   All these devices can be used for both monitoring and mass trapping of stored grain insects. It is important to note that even a single live insect presence in food grain can’t be tolerated as they build up and cause enormous loss in storage due to their high reproductive rate.                           


  • A main tube, insect trapping tube and a detachable cone at the bottom.
  • Equispaced perforations of 2 mm diameter are made in the main tube.


  • Insects love “AIR” and move towards air. This behaviour of the insect is exploited in this technology

Method of working

  • The insect trap has to be kept in the grain like rice, wheat etc., vertically with the white plastic cone downside as shown the figure.
  • The top red cap must be with the level of the grain. Insects will move towards air in the main tube and enter through the hole.
  • Once the insect enters the hole it falls down into the detachable white cone at the bottom. Then there is no way to escape and the insects are trapped forever.
  • The white detachable cone can be unscrewed once in a week and the insects can be destroyed.

Salient Features

  • No chemicals
  • No side effects
  • No maintenance cost


  • TNAU Insect traps are excellent insect detection devices in food grains and more effective in the detection of stored grain insects namely Rhyzopertha dominica (F.), Sitophilus cryzae (L.) and Tribolium castaneum (Herbst) in stored food grains both in terms of detection as well as number of insects caught than the standard normal sampling method (by spear sampling).
  • The detection ratio (trap : normal sample) is higher in trap than of normal sampling method by factors ranging from 2 : 1 to 31 : 1.
  • The insects catch is also higher in the probe trap than the normal sampling method by factors ranging from 20 : 1 to 121 : 1. They are also good mass trapping devices when used at 2 – 3 numbers / 25 kg bin (28 cm dia and 39 cm length).
  • They should be placed at top 6 inches of the grain, where the insect activity is seen during early period of storage.
  • They can remove > 80% of the insects within 10 –20 days.


  • Pitfall traps are used for capturing insects active on grain surface and in other layers of grain. (Monitoring and mass trapping tool).

Image titleStandard Model

Image titleTNAU Model

Image titleTNAU Two-in-one Model

Image titleIndicator Device


Standard Model

  • Standard model of pitfall trap has 2 parts, perforated lid (2 mm (or) 3 mm) and a cone shaped bottom portion. ·
  • Application of special coating with sticky material on the inner side of cone to hold trapped insects is necessary 

TNAU Model

  • TNAU model has perforated lid, cone shaped bottom which tapers into a funnel shaped trapping tube.
  • Hence sticky coating is dispensed with
  • Commercial model is in plastic, simple and economical (cost per trap is Rs. 25/- only).
  • Easy to handle.


  • The probe trap containing the components namely the perforated tube, pitfall mechanism, a collection tube and the cone shaped pitfall trap with a perforated lid and the bottom tapering cone were combined as a single unit.
  • Combination of probe and pitfall increase the trapping efficiency of insects. Best suited for pulse beetles as they are seen only on grain surface wandering here and there.
  • It does not require tedious procedures like coating the inner surface of pitfall cone with sticky materials before trapping to hold pulse beetles.
  • Beetles are captured alive in this trap, which may facilitate release of pheromone and there by attract more insects.


  • Device consists of a cone shaped perforated cup (3mm perforation) with a lid at the top.
  • The cup is fixed at the bottom with a container and circular dish, which are to be smeared with sticky material like vaseline. Farmers, before storing their pulses, should take 200 g of pulses to be stored and put them in the cup.
  • When the field carried over beetles start emerging, due to their wandering behaviour, they enter the perforations and get slipped off and fall into the trapping portions.
  • As they stick on to the sticky materials, farmers can easily locate the beetles and can take out the bulk-stored pulses for sun drying. The device with 2mm perforations can be used for cereals.
  • This will help in eliminating the initial population, which acts as the major source for further build up. Thus, timely detection will help the farmers to preserve their valuable pulses during storage.


  • TNAU insect removal bin can remove insect automatically. The structure has 4 major parts namely outer container, inner perforated container, collection vessel and the lid.
  • The model exploits wanderin behaviour of stored product insects as well as the movement of these insects towards well aerated regions. The grains are held in the specially designed inner perforated container.
  • The space between inner and outer container provides good aeration for the insects. Insects, while wandering, enter the perforation to reach the aerated part and while doing so, get slipped off and fall into the collection vessel through a pitfall mechanism provided in the collection vessel.
  • In order to quickly collect the insects, as and when they emerge from grains, perforated (2 mm) rods are fixed in the inner container.
  • The container will be useful for storing rice, wheat, broken pulses, coriander etc. The insects such as rice weevil, lesser grain borer, red flour beetle, saw toothed beetle, which are commonly found attacking   stored grains can be removed automatically by storing grains in this container.
  • Within a very short period of 10 days a majority of the insects (more than 90 per cent) can be removed from the grains. The containers are available in 2 kg, 5 kg, 25 kg, 100 kg and 500 kg capacities.Image title


  • Grains (paddy and sorghum) stored in Automatic insect removal bin  (100 kg and 500 kg) recorded only 1 – 4% damage by insects compared to 33 to 65% damage in ordinary bin after 10 months of storage.
  • The population of insects (R. dominica, S. oryzae)ranged from 0 – 2 / kg in grain stored in 100 kg. Automatic insect removal bin compared to 5 – 191 / kg in ordinary bin after 10 months of storage.


  •  The UV light trap mainly consists of an ultraviolet source (4 W germicidal lamp).
  • The lamp produces ultra-violet rays of peak emission around 250 nano meter.
  • The light is fitted at the centre of a funnel of 310 mm diameter at the top and 35 mm diameter at the bottom.
  • The bottom end of the funnel is attached with a transparent plastic container for collecting the trapped insects.
  • To hang the unit at desired points, three hooks have been provided at the periphery of the funnel. The unit is also provided with a tripod stand.
  • The UV light trap can be placed in food grain storage godowns at 1.5 m above ground level, preferably in places around warehouse corners, as it has been observed that the insect tends to move towards these places during the evening hours.
  • The trap can be operated during the night hours.
  • Lesser grain borer the light trap attracts stored product insects of paddy like lesser grain borer, red flour beetle, and saw toothed beetle, in large numbers.
  • Psocids which are of great nuisance in godowns are also attracted in large numbers.
  •  Normally 2 numbers of UV light trap per 60 x 20 m (L x B) godown with 5 m height is suggested.
  • The trap is ideal for use in godowns meant for long term storage of grains, whenever infested stocks arrive in godowns and during post fumigation periods to trap the resistant strains and left over insects to prevent build up of the pest populations.
  • In godowns of frequent transactions the trap can be used for monitoring.Image title


  • It has been found that two traps kept at the corners of the warehouse (60m x 20m x 5m) can catch around 200 insects/day even from a godown where normal sampling did not show any insect presence, thus indicating its effectiveness as a monitoring and mass trapping device.
  • It has been recorded around 3000 lesser grain borer on a single day from single trap kept in a paddy godown.


  • TNAU-Stored Grain Insect Pest Management Kit containing prototypes of all the devices along with a CD-Rom about the devices and how to use them.
  • This kit will be of great use in popularization of the technologies across the country.
  • The kit will be an ideal “hands – on training” tool for Education, Extensioncenters (KVK, Plant clinic, save grain centers) and also for private ware housing.
  • This TNAU kit is the first of its kind in the world.

Grain Storage

Stored grains protection can be divided into two broad areas based on the type of intervention followed. 

Preventive measures and
Curative measures

I. Preventive measures 
Sanitation and handling of grains

  • Remove dirt, debris, mud balls, foreign particles, insects and infested grains from healthy grains that will reduce insect infestation.
  • Proper handling of grains and avoiding hooks on storage bags help minimize exposure to insects
  • Bags should be stacked on wooden dunnage 0.5 metre away from the wall
  • Bags should be stacked in rows having space of nearly 2 to 3 metre in-between height of a row should not be more than 15 bags leaving about 1/5thspace of total storage from the roof.
  • Likewise bulk storage structures should also be kept away from the ventilators or doors
  • Drying of grains Grains are harvested at a moisture content ranging from 20-28%
  • Moisture content should be brought to 12-13 percent
  • Sun drying and use of mechanical dryers can be opted to bring down moisture.
  • Improper drying of paddy grains during post harvest operations not only enhances the insect infestation but also enhances breakage during milling.
  • Staggered sun drying with short exposure to sun spread over large number of days (9-11 am for 8 days) reduces insect infestation.
  • Use of improved storage structures Gunny bags or jute bags with close weaves can reduce insect infestation.
  • Impregnation of gunny bags with insecticides can prevent entry of insects (Prakashet al., 1981).
  • Polythene lined gunny bags were suggested by Muthu and Pingale, 1955).
  • Polyester- polythene 400 gauge lined canvas was found to be resistant to all types if insect attack.
  • Improved storage structures namely aluminum bin, Pusa bin, Pusa cubicle PAU bin, IGSI domestic bin
  • TNAU insect removal bins have been found very effective for bulk storage and reducing insect damage.

Dis-infestation of stores/receptacles

  • Treatment of bulk and bag storage structures with insecticides is an important practice to avoid latent infestation in reused bags and bulk storage structure.
  • The insecticides commonly recommended are malathion and dichlorvos.
  • Legal method In India, the Destructive insects and Pests Act started in 1914.
  • Plant Quarantine Order 2003, govern the regulation or restriction of movement of insects through commodities into the country and among different areas within the country.
  • Grains or other commodities are thoroughly checked and treated at ports to avoid entry of insects.

II. Curative measures Physical control measures
1. Use of low and high Temperatures The insects can be controlled either by increasing or decreasing storage temperature.

  • Optimal temperature for most of the storage insects is between 25 and 33o C.
  • Temperatures between 13 and 25o C will slow development.
  • High temperatures of 35o C and above will stop development.
  • Refrigerated aeration of grains stored in bins gave results on par with insecticide treatment in Australia
  • USA and Israel in controlling storage pests (Navarro and Calderon, 1982).
  • High temperature disinfestations using heated air grain driers, fluidized beds, spouted beds, pneumatic conveyors, a counter flow heat exchanger, high frequency waves microwaves, infra red waves and solar radiations have been satisfactorily used for in disinfesting grains.

2. Mixing of inert dust

  • Inert dusts used in stored-product protection can be categorized into 4 groups.
  • The 1st group consists of clays, sand, paddy husk ash, volcanic ash and wood ash.
  • The 2nd group consists of a great number of minerals such as dolomite, magnesit copper oxy-chloride, rock phosphate, ground sulfur, lime limestone and common salt.
  • These minerals have been used at rates greater than 10 grams per kilogram of grain
  • The 3rd group consists of dusts that contain synthetic silica (silicon dioxide).
  • These materials are light and hygroscopic, and are produced by drying an aqueous solution of sodium silicate.
  • The 4th group consists of dusts that contain natural silica, such as diatomaceous earth (DE), which are made up fossilized skeletons of diatoms.
  • Many DE dusts are now commercially available and used in many developing countries for managing stored-product insects and mites, or to improve fumigation efficiency

3. Activated clay

  • Activated clay (kaolin) has been used in protecting grains from the attack of storage insects.
  • This method is very effective against most of the storage pests and nontoxic to higher animals.
  • The kaolinate clay after successive processes of activation with acid and heat can be used as physical poison.
  • The raw clay (kaolinate clay) having 45% silicondioxide and 38% alumina can be obtained from the Neyveli Lignite Corporation, Neyveli, Tamil Nadu

4. Irradiation

  • Low dose irradiation completely kills or sterilizes the common grain pests, and even the eggs deposited inside the grains.
  • Only a single radiation exposure of grains is sufficient for disinfestations.
  • Ideally suited for large-scale operations, thereby offering substantial economic benefits.
  • Effective process for disinfestations of certain pre-packed cereal products.
  • Low dose applications (Less Than 1kGy) has been found useful for Insect disinfestationin stored grain, pulses and products (Tilton et al. 1974)

5. Use of controlled atmosphere

  • The normal storage atmosphere (or earth’s atmosphere) contains 78% Nitrogen (N2), 21% Oxygen (O2) and 0.03% carbon dioxide (CO2).
  • In grain storage, insects can be controlled by decreasing O2 or increasing CO2 or N2 concentration in the atmosphere thereby interfering with the normal respiration of insects.
  • This is achieved by modified atmospheric storage, controlled atmospheric storage or airtight storage

Mechanical control measures

  • Several mechanical devices have been developed both for monitoring and mass trapping stored product insects.
  • Entoleters are used primarily in flour mills.
  • Kernels infested with primary feeders such as Sitophilus sp. R. dominica break apart and are separated from intact kernels.
  • Other traps: Probe trap, Pulse Beetle Trap, Light traps, Sticky traps, Bait traps, Pheromone traps and TNAU Automatic Insect Removal Bin.

Use of plant products

  • Neem leaf powder, Nochi leaf powder, turmeric powder, Sweet Flag (Vasambu) Rhizome powder all at 10g /kg have been found to be effective against storage pests.
  • Experimental results show that the fresh leaves of Nochi mixed with paddy at the rate of 2% w/w protected the grains from insect attack for 9 months.
  • Garlic extract is yet another plant product which is nontoxic and was found to be grain protectant.
  • The water extract (0.02%)of bulbs mixed with the grains at the rate of 2 litres/ 100 kg grains can give good protection to paddy grains against insect attack.

Management of stored product pests in Warehouses

  • Maintain store house hygiene brushing the cracks, crevices and corners, removing all debris and cleaning the entire godown before storing the grains
  • Reduce moisture content below 10 %
  • Dry all the bags, bins etc in the sun
  • Eliminate conditions which favour storage pests sieving and removing all broken grains, stitching all torn bags before filling
  • Maintain good storage conditions by providing dunnage leaving gangway or alleyway of 0.75 to 1 m all around for aeration inspection prevention of moisture seepage and for fumigation and chemical spraying. Treat the walls, dunnage materials and ceilings of empty godown with Malathion50 EC 10 ml/l or DDVP 76 WSC 7 ml/l at 3 l spray solution per 100 sq m.
  • Air charge or treat alleyways and gangways with Malathion50 EC 10 ml/l or DDVP 76 WSC 7 m (1 litre of spray fluid /270u.m)
  • Apply stack spraying over the bags with Malathion50 EC 10 ml/l @ 3litre of spray fluid /100 sq.m


  • Decide the need for shed fumigation (entire store house or godown) or cover fumigation (only selected blocks of bags).
  • Check the store house/godown and the black polythene sheets or rubberized aluminium covers for holes and get them ready for fumigation
  • Choose the fumigant and work out the requirement based on the following guidelines.
  • Aluminium Phosphide For cover fumigation: 3 tablets of 3 g each per tonne of grain.
  • For shed fumigation: 21 tablets of 3 g each for 28 cubic metres.
  • Period of fumigation: 5 days,
  • In case of cover fumigation Keep ready sand-snakes.
  • Insert the required number of aluminum phosphide tablets in between the bags in different layers.
  • Cover the bags immediately with fumigation cover
  • Plaster the edges of cover all round with wet red earth or clay plaster or
  • Use sand-snakes to make leak proof.
  • Keep the bags for a period of 5 -7 days under fumigation
  • Remove the mud plaster after specified fumigation period and
  • Lift cover in the corner to allow the residual gas to escape.
  • Allow aeration and lift cover after a few hours.
  • Follow similar steps in case of shed fumigation also

Prophylactic treatment of grains/seeds:

  • If the produce is meant for seed purpose, mix 1 kg of activated kaolin or 1 kg of lindane1.3 D or 1 kg of malathion 5 D for every 100 kg of seed and store/pack in gunny or polythene lined bags
  • If the produce is meant for grain purpose, Mix 1 kg of activated kaolin for every 100 kg of grain and store.
  • To protect the pulse grains, Mix activated kaolin at the above dosage or any one of the edible oils at 1 kg for every 100 kg of grains or Mix 1 kg of neem seed kernel powder for every 100 kg of cereal or pulse and store.

NOTE: Never mix synthetic insecticides with grains meant for consumption

Storage Structures

  • To cope with the current and future demand of the increasing population for the food grains, it is emphasized to reduce the loss of food during and after harvest.
  • Food grains are stored for varying periods to ensure proper and balanced public distribution throughout the year.
  • Post harvest losses in India are estimated to be around 10 per cent, of which the losses during storage alone are estimated to be 6.58 per cent.
  • But, with the advent of improved agricultural technology, the farmer can afford to store the grains for longer period with minimum loss.
  • The produce must be thoroughly cleaned and graded,
  • Dried to the safe storage moisture level of 10-12 % for food grains and 7-9% for oil seeds (on wet basis) for a safe storage period of 6-12 months.
  • Storage structures should to be properly repaired, cleaned and disinfected,
  • Structures should bear the load of grain stored and do not permit contact/exchange with outside humid air,
  • Structures should be constructed in the coolest part of the house/ farm.
For best storage performance

An ideal storage facility should satisfy the following requirements

  • It should provide maximum possible protection from ground moisture, rain, insect pests, moulds, rodents, birds, fore etc.,
  • It should provide the necessary facility for inspection, disinfection, loading, unloading, cleaning  and reconditioning.
  • It should protect grain from excessive moisture and temperature favourable to both insect and mould development,
  • It should be economical and suitable for a particular situation

Image titleGrains can be stored in bulk or in bags.
(a) Bulk (open) storage: Farm products are sometimes stored in surface structures in a loose form. It is preferred over bag storage for the following reasons

  • Large quantities of food grain can be stored
  • No difficulty in loading and unloading of grain
  • No need to purchase storage containers like gunnies
  • Insect incidence is less than bag storage, even this can be eliminated by fumigation in situ
  • Avoids waste from leaking bags
  • Easy inspections- save labour and time.

Image title

(b) Bag storage
Storage farm products are stored after placing them in gunny bags made of jute. 

  • Each bag contains a definite quantity which can be bought, sold or dispatched without difficulty;
  • Bags are easier to load or unload.
  • Infested bags-can be removed and treated easily
  • Problem of the sweating of grains does not arise because the surface of the bag is exposed to the atmosphere.

Storage structures used by the farmers are

  • Gunny bags of different capacities (35, 50, 75 and 100 kg) with or without inside
  • Plastic lining.
  • Mud bins having 100 – 1000 kg capacity
  • Baked earthen containers of 5- 100 kg capacity
  • In heaps on flat floor in the corner of houses (100- 1500 q).
  • Bamboo structures
  • Wooded bins and
  • Underground structures







1.Bamboo Structures

Split bamboo woven in the form of a  cylinder with wide base and narrow mouth

Paddy, wheat and sorghum

500 kg

Life 4-5 years. Weight loss due to insect attack is 5 % in paddy and 15 % in sorghum.

2. Mud and earthen  structures

Clay, straw and cow dung- 3:3:1. earthen structures are made, sun dried and then burnt in fire

Paddy, wheat, sorghum, oil seeds and pulses

5 to 10 q

Life 8- 10 years. During rainy season develop cracks and moisture absorption followed by insect and mould infestation.

3.Wooden structures

Local wood is painted black. At the top, 30cm x 20 cm inlet and at the bottom 30 cm x15cm outlet is provided


10 q

15- 20 years. Neither airtight nor moisture proof.

4. Brick structures

Rectangular, structures built as part of the house, with brick in cement or lime mortar having a wall thickness of 40 –50 cm. At the top 50x 50 cm inlet and at bottom 15 x15 cm outlet is provided.

Paddy, sorghum and wheat

25- 30 q

25- 30 years. High initial cost, not insect and moisture proof.


Circular pits vary from 100 – 400cm in depth and 50 – 100cm dia at neck and250 – 300 cm at the bottom. For filling and emptying there is an opening at the top. Before filling the sides and bottom are packed with straw and husk. After filling the pit is gain covered with straw and stone, the finally with mud.


100 –200q

Safe against insects but, loss of seed viability and handling difficulties made it out of date

6. Miscellaneous plant materials 
a. Paddy straw


b. Stem of vitex and pigeon pea stalks


c. Bottle gourd shells


a. Paddy straw is wound in the form of rope to varying diameter 
b. stems wound like a bin and both sides are plastered with mud and cow dung

 c. empty shells are used


Paddy, other cereals and pulses

Paddy and
Other cereals

Pulses, gourd seeds




1-2 q



2-5 kg


Not insect and rat proof





Only small quantity of seed lots.

7. Metal corrugated G.I. sheets

Sheets of about 3 m high are held vertically along one edge and edges of the other sheets are overlapped and bolted to each other. Thus the circle with 2-4 m dia. is completed with many such sheets. They are covered on the top with the plain M.S. or G.I. sheets.

Various types of grains



8. Hessian cloth bags


9. Gunny bags


Improved rural-level storage structures

1. Bitumen/ coal tar drum

  • An alternate model of metal bin, low cost with similar technical performance.
  • These bins are of 520 mm dia and 900 mm height. They can store 1.5 q of wheat and 1.2q of Bengal gram.

2. Hapur bin/ Kothis

  • Circular bins of 2, 5, 7.2 and 10 q capacities and have potential to meet requirements of even large farmers.

3. Udaipur bin

  • These bins are made out of used coal tar drums.
  • These can stock 1.3 q of wheat and maize.
  • These bins can be made to have more airtight lid if the drum outlet end is given small cut to unload the bitumen.
  • These bins are suitable for storing of food grains for short duration and can be adopted by small farmers.

4. Stone bin

  • Stone bin (Chittore bin) is made of locally available 40 mm thick stone slabs with dimensions of 680 mm x 1200 mm with square cross-section.
  • The inlet and outlet are made of asbestos. This bin has a capacity of 3.8 q.

5. Bamboo bin

  • These bins are made of two walls of bamboo with polythene lining in between and have varying capacities.
  • These bins are suitable for short – duration storage and can be adopted by small and marginal farmers.

6. Baked clay bin

  • Baked clay bin of 7q capacity (paddy) is made of 16 burnt rings jointed by mud plaster; cement mortar and cow dung coatings one after another.
  • The ends of the rings are made in such a manner that they fit into each other.
  • These rings are kept on a polythene sheet covered and plastered platform of brick mansory and cement sand mortar.
  • An outlet is provided for the discharge of the grain.
  • The top is covered with a mild steel lid. Because of the low cost and good performance these are particularly useful for small and marginal farmers who do not store their produce for longer duration.

7. PKV bin

  • Made from green bamboo splits into suitable sizes.
  • The tunnel, outlet flap valve and complete stand can be fabricated in a workshop.

8. Pusa bin

  • It is a modification of the ordinary mud storage structure commonly used in villages.
  • To provide moisture proof and airtight conditions, polyethylene film of 700 gauge thickness has been embedded at the top, bottom and on all the sides of the mud bin.
  • The embedding process provides mechanical support and safety to polyethylene film.
  • The construction of outer walls with burnt bricks up to 45 cm height makes the structure rat proof as well.
  • The bin is constructed with un burnt bricks on burnt bricks or concrete floor to avoid rat burrowing.
  • The grain and seed both remain safe in the bin for more than one year with proper precautions.

9. Pusa Cubicle

  • This is a room like structure ( 3.95 x 3.15 x 2.60 m), a modification of Pusa bin to provide large storage capacity of 24 tonnes on a platform of 3.73 m x 2.93 m x 0.07 m is made with unburnt bricks on a concrete floor (except 22 cm of outer sides with burnt bricks).
  • A polyethylene sheet is placed on this platform and another platform of similar dimension is made with unburnt bricks.
  • The 22 cm thick inner walls are constructed upto 2.6 m height. A wooden frame of 1.89m x 1.06 m for door is fixed in the front side of 3.95 m wall.
  • The roof can be made by wooden beam placed at 15 cm distance and covered with unburnt bricks.

10. Pusa Kothar

  • Presently storage is practiced in small compartments of a room (5.3 m x 2 m x 4 m) called kothar.
  • The roof is constructed with the help of wooden poles and mud slabs, leaving near the front wall three filling holes each of 0.5 m x 0.5 m size.
  • Two out lets of G.I. sheets of 15 cm dia. and 30 cm length are fitted at the floor wall on the front side.

11. Metal bins

  • Bins made of steel, Aluminium R.C.C are used for storage of grains outside the house.
  • These bins are fire and moisture proof.
  • The bins have long durability and produced on commercial scale.
  • The capacity ranges from 1 to 10 tonnes. Silos are huge bins made with steel/ aluminium or concrete.
  • Usually steel and aluminium bins are circular in shape.
  • The capacity of silo ranges from 500 to 4000 tonnes. A silo has facilities for loading and unloading grains.


  • Food grains have to be stored and preserved on scientific lines in godowns till they are issued to consumer.
  • Te bags containing food grains cannot be just dumped inside the godown, for it will not facilitate proper storage.
  • Proper stacking ensures free access to the stocks in all parts of the godown for inspection and helps in effective disinfestations work. Generally, three methods of stacking are being followed: 1. Simple, 2.Cross and 3. Block method.

Steps necessary for good storage practice in respect of all food grains

  • Stored product pests can be managed either behaviouraly (traps viz., probe traps, light traps, pitfall traps etc.,) or with several preventive and curative measures (both chemical and non-chemical methods).
  • Once a facility is obtained, a number of steps are to be taken to ensure safe storage of grains. These steps comprise

1. Before storage

  • Checking for leakage of rain water and sufficiency of drainage facilities
  • Cleanliness of the facility and environment
  • Assessment of capacity of the facility
  • Pesticidal treatment
  • Security and firefighting arrangements and
  • Repairs to available equipment

2. After receipt of grain

  • Inspection for variety and soundness of quality
  • Inspection carefully for infestation, it any, and when present, for type and extent
  • of infestation,
  • Inspection whether grain has excess moisture, whether it had been heated up in
  • earlier storage and has any musty or rancid odour
  • Any grain rendered wet or damaged to be segregated and salvaged with facilities
  • available and check the weight received

3. During storage

  • Maintenance of cleanliness
  • Ensuring aeration where necessary
  • Checking for leakage after rains
  • Inspection for insects, rats and mites at fortnightly intervals
  • Watch for advancement in deterioration, if any,
  • Pesticidal treatments necessarily based on observations
  • Ensuring disposal where called for, and
  • Arrangement for segregation, salvage and processing, wherever, damage owing to leakage of water and other causes might have taken place.

Chemicals that can be directly applied to grains are formulations of chemicals having residual toxic or repellent action or both. Those are applied directly to the grain to prevent damage by stored product pests. Eg., clay minerals (red earth, Kaolin) before 1950. Now their use is restricted only to seeds and grains meant for animal feed. These grain protectants can be applied in the form of spray/ dust on the uninfested grain.

Advantages over fumigants

  • Used as a prophylactic treatment
  • Can be effective when the grains are stored in loose containers where fumigation is not possible
  • Less dangerous than fumigants
  • Don’t affect germination adversely
  • One application at harvest time is sufficient for one year

1. Pyrethrum synergized with PBO: safest of the grain protectants available and approved for use. Available as powder 1 % PBO +0.8 % pyrethrum, 0.83 lb synergist+ 0.6 % pyrethrum also be applied in the form of spray 3-5 gallons/ 1000 bushel, 0.6 lb synergist+0.066 lb pyrethrum.

2. Premium grade Malathion: Foul smell is removed. Can be directly applied over the grain as 1 % D or as a spray 57 EC. Other chemicals include: Carbaryl, Dichlorvos, Fenitrothion, Malathion, PBO, Pyrethroids (Deltamethrin, Fenvalerate).