Rice is stored in the forms of paddy or rough rice, milled raw rice,
milled boiled rice, bran, broken grain either on the farm or in the
mills and in commercial warehouse.
Paddy is stored either for seed or for hand pounding or for milling
as needed.
Rice (husked rice), either semi-polished (4-5% removal of bran) or
polished (10 - 12 % removal of bran), is stored in jute bags.
According to the consumers' liking the raw rice has to be stored
for at least over a year before it is consumed while with parboiled
rice no such condition is needed and is consumed as fresh.
In store the rice develops rancidity and heating due to either insect
attack or excess moisture.
The rice can safely be stored in warehouses without reduction in
quality and quantity of rice.
If the warehouses are not aerated or damp-proof, the free fatty acid
rises from initial 35 to 320.
The rice becomes unacceptable when acid reaches 350 unless it is
remilled.
Brokens
Broken's are of two types - big broken's are generally over 1/4 the
size of the kernel and small broken's are less than 1/4th.
These are graded and filled in separate jute bags.
The normal storage period for broken's is 2 to 6 months because they
develop rancidity very soon.
Bran
Bran can be stored for short period because it develops rancidity
very fast.
It is always better to dispose it off within a week's time after it
is obtained from mill .
Grain Storage
The key to good storage is hygiene and grain moisture contents.
The target moisture for storage is less than 14%.
The following table shows the storage possibilities and problems associated
with difference grain moisture contents.
Grain moisture content
(%)
Safe Storage
Possible Problems
> 40
Germination
18
2 weeks
Fungal growth
> 14
12-14
1 year>
> 8
Insect damage
8-10
> 1 year
Calculation of moisture content
Moisture content can be on a wet (MC wet) or dry
(MC dry) basis:
MC wet = Weight of moisture in wet grain * 100/(weight
of wet grain)
MC dry = Weight of moisture in wet grain * 100/(weight
of dry grain)
Grain moisture depends upon the temperature and the
relative humidity of the air.
The following table shows this relationship.
Hygiene for storage
Keep storage areas , crevices, wooden pallets etc clean by spraying
with the recommended insecticide to disinfect insect breeding places.
Place sticky traps in the drying and storage areas for rats.
Storage rooms should be physically rodent and bird proof, if possible.
If necessary, treat storage sacks with insecticide to prevent insect
infestation.
This however is a dangerous practice if there is a chance that the
seeds will be milled for consumption, and therefore is not recommended.
Inspect the stored seeds once a week for signs of insect infestation.
If there is infestation, under the direction of a trained pest control
technician, the storage room or the seed stock may be enclosed hermetically
with tarpaulin and fumigants.
Phostoxin is used by the grain milling industry.
This will kill all insects, larvae, and rodents in the enclosure.
For long term seed storage, store the seeds in bags in storerooms
with controlled temperature and relative humidity.
The recommended storage environment for rice seeds are less than 20ºC
and 40% R.H.
In this conditions both fungi and insects will be inhibited.
The difference constituents of rice undergoing storage are
Paddy,
Milled-raw rice,
Milled-boiled rice,
Bran,
Brokens
Paddy is stored either on the farms or in the rice mills.
Rice undergoes storage at the mills and in commercial warehouses.
Bran, brokens and germs are stored only in the mills from where these
are sold and for end use.
Paddy
A sizeable quantity of paddy is held on the farms either as seed,
or for hand-pounding or for milling and consumption, as required, paddy
harvested in October-December is mostly retained on the farms.
Summer and autumn crop paddy is not held on the farms, because of
drying problem and susceptibility to discoloration.
Storage in farms
On the farm, paddy is stored indoors in jute bags or in containers
made of rope (morai), straw (Bharola), bamboo (Kanagi) or mud (Kuthla
or Kuthi).
When quantities held in storage exceed a tone, the containers made
of rope, straw or bamboo are used and these are placed out doors.
The outdoor containers are covered with a sloping straw roof.
Capacity of the out door containers ranges between 1.5 and 10 tones.
To avoid storage losses, use of either cement or steel bins are recommended.
Storage in mills
In the mills, paddy is placed in chambers or in the open either loose
or in jute bags.
The period of storage in the mills ranges between 2 and 8 months.
Paddy kept in the chambers without adequate protection from pests
and moisture sustain a loss both in quantity and quality.
In the open, weather conditions cause either sprouting or discolouration.
Birds, rats, monkeys, squirrels, and insects attack paddy kept in the
open and cause quantitative losses and also contaminate the grain with
undesirable substances.
Storage in Ware houses Paddy stored in warehouses which are damp and
rodent-proof, suffered a loss only on account of reduction in moisture
content.
In these warehouses, paddy filled in jute bags is placed in standard-sized
lots of 6x10x6 m.
For keeping paddy in the open, land that is not susceptible to flooding
is selected and is paved either with bitumen or with bricks.
Paddy filled in jute bags is then placed in lots of 6 (breadth) x
10 (length) x 7 (height) m after arranging either wooden pellets or
concrete blocks on the ground that provide for a air-gap of 15 cm between
the floor and the bag.
The lots are then covered with polythene to protect the grain from
weather and pests.
The loss in this storage is observed to be only quantitive and brought
about by reduction in moisture content.
It has been possible to hold large quantities of paddy free of spoilage
for a year in this type of plastic storage which does not have a conventional
roof over it and is exposed to the weather.
Storage in silos
Silos have been used for storage of paddy in India during the last
few years.
These are either steel or concrete circular silos, capacity ranging
between 350-600 metric tones (for wheat this capacity is 500-850 metric
tones).
Initially, flat bottom silos were used with provision of screw conveyors
at the bottom to take paddy out.
Unloading of paddy from flat bottom silos was found slow and labourious.
Only hopper bottom silos are now in use for paddy storage.
The silos storage unless adequately understood and properly supervised
results in discolouration and spoilage of paddy.
The funnelling, takes place while unloading operations are in progress,
leaves some paddy undistrubed on the sides of the silos.
Special arrangements are necessary to effect a turn-over for the paddy
that remains on the sides of the silo.
In a silo, paddy can be stored in the same condition and without any
loss in quantity.
It is also possible to adjust the condition of paddy at the time of
delivery with the result that maximum out-return of rice can be obtained
from such paddy in the course of milling
Cost details of different storage methods
Item
Conventional warehouse
(storage in jute bags)
Silo (Concrete)(Storage
in loose)
Plastic storage with
concrete flooring (storage in jute bags)
1. Initial construction
230.0
350.0
25.0
2. Interest depreciation and maintenance
21.0
33.0
10.0
3. Storage charges per tonne per year (including
loading in and out charges)
33.71
14.35
32.71
Total storage cost (2)+(3)
54.71
47.35
42.71
Rice
There is no alternative at present to storage of rice in jute bags.
Bulk storage of rice has not been possible so far because of deleterious
effects of mechanical pressure.
Unpolished or brown rice can be stored for short periods provided
the bran layer is intact.
The rice moved and/or a stored in India :
Semi-polished (4 to 5 per cent removal of bran) or
polished (10-12 per cent removal of bran).
Traditionally, consumers prefer raw rice that has undergone storage
over a year.
In case of boiled rice, the preference is for fresh milled rice.
In storage, rice tends to develop rancidity and heating as a result
of either insect attack or excess moisture.
Presently, sizeable quantities of semi-polished raw and boiled rice
are held in buffer storage for periods varying between 4 and 20 months.
It is noticed that with standard storage practices (IS 6151-I-71)
in warehouses that are well-aerated and damp proof as well as rodent-proof,
when the stack size is 10 m x 6 m and height is 16 bags, and when initial
moisture is not in excess of 14 per cent and insecticidal treatments
are carried out in time, the only loss to rice in storage is that brought
about by reduction in moisture content.
When storage is done in warehouses that are neither aerated nor damp-proof,
in storage of 6 months, free fatty acidity rises from initial 35 to
320.
Rice becomes almost unacceptable when it reaches 350, unless it is
re-milled.
Rice that is polished is less susceptible to development of rancidity
on storage up to two years.
Brokens
Brokens are graded either as big or small.
Big brokens generally are over 1/4th the size of the
kernel and small brokens less than 1/4th .
All brokens are packed in jute bags and the filling
ranges between 75 and 90 Kg.
Brokens, particularly small brokens develop rancidity
very soon.
The normal storage period is 2-6 months.
Insects are mainly responsible for causing deterioration
in storage.
Spoilage, is heavy, wherever bird and rodent damage
exists, causes sizeable quantitative loss.
The demand for brokens being good, the aim generally
is to dispose of these as quickly as possible.
When the demand slows down, however, alternative uses
for brokens will need attention and then production of clean brokens
and grading them to set standards would assume significance.
There is a greater danger in brokens of quantititive
and qualitative loss, due to insects, rodents and birds, as compared
with rice.
Bran
Bran is filled in jute bags of 60-70 kg capacity.
Bran obtained from huller mills is cleaned and disposed
off in week's time as cattle/poultry feed.
Bran from disc huskers and rubber-roll shellers is
used mainly for oil-extraction and subsequently is either exported
or used as cattle feed.
Bran is not kept in storage for long because of rapid
development of rancidity
Factors affecting storage
Several factors that influence the storage
of food grains are moisture content, quality of produce, climate,
storage conditions.
The most important factors deciding the
storability of the produce is moisture content of grains. High moisture
content of grains results in severe attack of insects and microorganisms
in addition to heating and germination.
Moisture content of paddy for safe storage:
Paddy , Raw Rice 14%
Parboiled Rice 15%
Among the climatic factors
Temperature
Light
R.H.
Are important factors influencing storage of food grains.
Temperatute
Respiration of grains increases with increase in temperature.
In addition temperature influences the metabolism, growth, development,
reproduction behaviour and distribution of insects.
Insect development is generally limited below 10ºC and above 45ºC.
Light
Light influences movement and development of stored grain pests.
In case of rice storage insects show photo negative response.
Darkness is necessary for egg laying.
Relative humidity
Under high R.H. moisture content of grains increases.
Tropical climate, in which temp and R.H. are high, are favourable
for the growth and multiplication of insects.
Because of favourable conditions throughout the year, pest problem
is continuous and high in tropical regions compared to temperate regions.
Storage practices in India
The storage function is as old as man himself, and is performed at
all levels in the trade. Producers hold a part of their out put on the
farm .
Traders store it to take price advantage.
Processing plants hold a reserve stock of their raw materials to run
their plants on a continuous basis.
Retailers store various commodities to satisfy the consumers day-to-day
needs.
Consumers, too, store food grains, depending on their financial status.
The storage of agricultural products is necessary for the following
reasons
Agricultural products are seasonally produced, but are required for
consumption throughout the year.
The storage of goods, therefore, from the time of production to the
time of consumption, ensures a continuous flow of goods in the market.
Storage protects the quality of perishable and semi-perishable products
from deterioration.
Some of the goods, e.g., woollen garments, have a seasonal demand.
To cope with this demand, production on a continuous basis and storage
become necessary.
It helps in the stabilization of prices by adjusting demand and supply.
Storage is necessary for some period for the performance of other
marketing functions.
For example, the produce has to be stored till arrangements for its
transportation are made, or during the process of buying and selling,
or the weighment of the produce after sale, and during its processing
by the processor.
The storage of some farm commodities is necessary either for their
ripening (e.g., banana, mango, etc.) or for improvement in their quality
(e.g., rice, pickles, cheese, tobacco, etc.), and storage provides employment
and income through price advantages.
For example, middlemen store food grains by purchasing them at low
prices in the peak season and sell them in the other seasons when prices
are higher.
Risks in Storage: The storage of agricultural commodities involves
three major types of risks.
These are as follows.
Quantity Loss
The risks of loss in quantity may arise during storage as a result
of the presence of rodents, insects and pests, theft, fire, etc.
Dehydration too, brings about an unavoidable loss in weight.
It had been estimated that about 10 million tonnes of food grains
are lost every year because of poor and faulty storage.
Quality Deterioration
The second important risk involved in the storage of farm products
is the deterioration in quality, which reduces the value of the stored
products.
These losses may arise as a result of attack by insects and pests,
the presence of excessive moisture and temperature, or as a result of
chemical reaction during the period of storage
Dehydration of fruits, vegetables and meat during storage may lower
their sale value.
Butter , if not properly stored, may become rancid, which reduces
its sale value.
The loss in the quality of farm products varies with their quality
at the time of storage the method of storage and the period of storage.
Price risk in storage
This, too, is a important risk involved in the storage of farm products.
Prices do not always rise enough during the storage period to cover
the storage costs.
At times they fall steeply, involving the owner in a substantial loss,
Farmers and traders generally store their products in anticipation of
price rise and they suffer when prices fall.
Storage structures of farm products are of two basic types,
depending on whether they are
Stored underground or
Above the ground.
There is no intrinsic difference between these two provided
that basic requirements of safe storage are met.
The advantages and disadvantages of these two types of storage
structures are given as follows:
Underground Storage Structures
Underground storage structures are dug-out structures similar to a
well with sides plastered with cowdung.
They may also be lined with stones or sand and cement. They may be
circular or rectangular in shape.
The capacity varies with the size of the structure. These structures
are known by difference local names in various regions.
In Rajasthan the under ground storage structures for food grains are
known as 'Khai'.
The advantages of underground storage structures are
Foodgrains in an underground storage structure are more free from
the seasonal variations in temperature and humidity provided that adequate
precautions are taken against the seepage of water in the structures,
especially in areas where the water table is high.
Underground storage structures are safer from threats from various
external sources of damage, such as theft, rain or wind. However, they
are not good when the quantity available for storage is small, and there
are a number of varieties to store.
The underground storage space can temporarily be utilized for some
other purposes with minor adjustments; and
The underground storage structures are easier to fill up owing to
the factor of gravity.
However, it becomes cumbersome to take out the grains from these structures.
The advantages of Surface storage structure
They can be maintained in more hygienic conditions by cleaning or
white washing them;
They are more convenient for inspection and the performance of various
operations during storage, such as spraying and dusting, fumigation
and turning of the grains; and the danger of heating up of grain due
to internal heat is less.
Limitations of surface storage structures
However, the cost of storage in terms of the maintenance of storage
structure, handling costs, and losses due to external factors are higher
in surface structures.
Vertical silos on the ground are often constructed for storage; but
these have a limited application because of their cost and the requirements
of energy for their operation.
The losses are low; but the absence of bulk transport facilities,
and the use of traditional handling and marketing methods make them
unsuitable in larger numbers.
Their utility for storage is at the ports for the export/import of
food grains.
The food corporation of India has undertaken the construction of vertical
silos (on the ground) at a few places.
Food grains in a ground surface structure can be stored in two ways
Bag storage or Bulk storage.
Bag storage
Farm products are stored after placing them in gunny bags made
of jute.
Storage in bags has following advantages each bag contains a
definite quantity which can be bought, sold or despatched without
difficulty; bags are easier to load or unload.
The bags which are identified as infested on inspection can be removed
and treated easily; and the problem of the sweating of grains does not
arise because the surface of the bag is exposed to the atmosphere.
Bulk or Loose Storage
Farm products are sometimes stored in surface structures in
a loose form,.
The advantages of this method are:
The exposed peripheral surface area per unit weight of grain
is less.
Consequently, the danger of damage from external sources is
reduced; and pest infestation is less because of almost airtight
conditions in the deeper layers.
These two points in favour of bulk storage are significant.
The only precaution necessary for bulk storage is to avoid the sweating
of grains.
Kothi or Mud Pots: These are cylindrical in and are made up of unburnt
clay mixture with straw and cowdung or cowdung, mud and bricks.
The capacity of these varies from one to 50 tonnes.
Kuthla: These are cylindrical bins of mud/brick mixed with straw
and cowdung.
Thekka: These are rectangular in shape and are made up of gunny or
cotton wound around wooden support.
Metal Drums: These are cylindrical in shape and are made up of iron
sheets.
Gunny Bags:These bags are made up of jute and are used for storing
food grains and oil seeds.
Essentials of a good foodgrains storage Structure Foodgrain storage
structures must have the following specific characteristics:
There must be enough strength in the walls and floor to support the
weight of the grain to be stored the structure should be inaccessible
to insects, birds, rodents, unauthorised persons and moisture to save
quality and quantity losses.
The structure should be free from excess heat or rapid changes in
temperature; and
The structure must provide for the easy entry and removal of the grain
as well as for the application of insecticides and pesticides, if there
is any need for them.
Improved grain storages structures .Keeping these points in view,
various institutes engaged in research have envolved stograge structures
for farm as well as for large-scale storage.
These improved grain storage structures are as follows.
For small scale storage
PAU bin: This is a galvanized metal iron structure designed by the
Punjab agricultural University, Ludhiana. Its capacity ranges from 1.5
to 15 quintals.
Pussa bin: This is a storage structure designed by the Indian Agricultural
Research Institute (IARI), New Delhi, and is made of mud or bricks with
a polythene film embedded within the walls.
Hapur Tekka: This is a storage structured designed by the Indian Grain
Storage Institute, Hapur.
It is a cylindrical rubberised cloth structure supported by bamboo
poles on a metal tube base, and has a small hole in the bottom through
which grain can be removed.
For Large Scale Storage
CAP Storage (Cover and Plinth): This has been developed by the Food
Corporation of India. It involves the construction of brick pillars
to a height of 14" from the ground with grooves into which wooden crates
are fixed and embedded with a polythene sheet.
The structure can be fabricated in less than 3 weeks.
It is an economical way of storage on a large scale.
Warehouse: Warehouse facilities in several areas have been created
by the Food Corporation of India, the Central Warehousing Corporation,
the State Warehousing corporations and Co-operative Marketing Organizations.
These are scientific storage structures constructed on a large scale.
Silos: The Food Corporation of India has constructed a few scientific
silos for storage of food grains in main surplus producing area like
Punjab.
In these structures, the grains in bulk are unloaded on the conveyor
belts and, through mechanical operations, are carried to the storage
structure.
The storage capacity of each of these silos is around 25,000 tonnes.
However, these are reported to be not being fully and regularly used
due to operational problems.
Costs and Returns on Storage The gross return on storage may be defined
as the increase in the price of the stored product at the time of storage
till it is "de-stored" and either sold or consumed.
The cost of storage should include the following.
The cost of the maintenance of the storage structure, i.e., depreciation,
repairs, insurance and interest on sunk capital; or alternatively, the
rent paid for hiring the storage structure.
Interest on the value of the stored goods;
Value of the quantitative and qualitative loss during storage;
Risk premium for a possible price fall and damage during storage;
The cost of protective material; for example; insecticides, pesticides,
rodenticides, fumigation, gunny bags , electricity, polythene covers;
and
Tax payments, payments to labour, etc.,
These items of costs may be grouped into fixed or variable costs,
depending on whether they vary with the quantity of goods stored or
not. For example, for a professional warehouse owner, the maintenance
and repair of the storage structure, the salaries of the permanent staff,
depreciation of the building, taxes, record keeping, etc., are fixed
costs.
For a farmer, however, who is trying to decide whether to sell or
store the grains for some time for later sale, all the costs are variable.
Whether it pays a farmer to store his farm produce may be worked out
with the help of the following formula NR = GR - C Where NR = Net returns
to storage GR = P1-P0 P0 = Purchase price or market price at the time
of storage.
P1 = Selling or market price at the time of de-storing C = Cost involved
in storage NR > 0, implies positive returns on storage NR < 0, indicated
negative returns on storage.
The percentage margin (MS) from storage may be calculated as:
MS = (P1-P0-C)/(Pq+100) *100
Items
Rs.
Charges of loading at the auction platform
and unloading in the warehouse
4.00
Transportation charges from the auction
platform to the warehouse
5.00
Warehouse charges for 9 months
45.00
Loss during storage and transit
5.00
Interest on Rs. 500 foregone for 9 months
@ 16% per year
60.00
Transportation charges from warehouse to
the auction platform
5.00
Loading at the warehouse and unloading
at the auction platform
4.00
Total:
Rs. 128.00
Using the notions given earlier, P0 = 500, C=128, NR will be positive
only if P1, pr price of wheat in the month of December is expected to
be more that the sum of P0 and C i.e., Rs. 628.00.
Cost Benefit Ratios of Various storage practices of paddy Cost of
storage varied among difference storage methods.
To show this the costs of storage per month of paddy were computed.
At the farmer's level the cost of storage comprise the interest on
initial investment (fixed capital), depreciation on establishment, repairs
and maintenance charges, insurance and taxes, interest on the value
of the stored goods, value of quantitative losses during storage, labour
charge for loading and unloading of grain, treating and conditioning
cost and transport charges.
Economics of storage in Puri of one quintal capacity.
Initial cost of storage structures (Puri of one q capacity) (Rs/q)
= Rs. 2.54 Initial cost of one quintal of paddy = Rs.480.93
Storage Charges
Treating and conditioning cost = Rs.5.38
Interest on initial investment at the rate of 12.5 per cent = Rs.0.43.
Interest on the value of the stored grain at the rate of 10 per cent
of the value = Rs.48.09
Value of the quantitative losses during storage = Rs. 4.98.
Storage charges / quintal - Rs. 58.89
Cost of paddy + storage charges/q = Rs. 539.60
Selling price of the grain/q = Rs.549.60
Net return per quintal of paddy = Rs. 9.78
Per centage margin from storage = 0.019.
No depreciation was charged on the Puri because it is constructed
every year.
Economics of Storage in Gade of one Quintal Capacity.
Initial cost of storage structures (Rs/q) = Rs.29.54
Initial cost of one quintal of paddy = Rs.445.33.
Storage charges
Treating and conditioning cost = Rs.3.50
Interest on initial investment at the rate of 12.5 per cent = Rs.3.69
Depreciation on storage structure/q = Rs.2.81(useful life taken as
10 years)
Repairs and maintenance cost/q=2.74
Interest on the value of the stored paddy at the rate of 10 per cent
= Rs.44.53.
Value of the quantitative losses during storage = Rs.39.69.
Storage charges/quintal = Rs.92.98
Cost of paddy/q + storage charges/q = Rs.538.31
Selling price after storage/q = Rs.550.00
Net return per quintal of paddy = Rs.11.69
Per centage margin from storage = 0.022
Economics of Room Storage of one Quintal Capacity (Rs/Q)
Initial cost of storage structures (Rs/q) = Rs.44.44
Initial cost of one quintal of paddy = Rs.415.78.
Storage Charges
Interest on initial investment @ 12.5 per cent = Rs. 5.55
Depreciation on storage structure/q = Rs.1.75
Repairs and maintenance = Rs. 1.59
Insurance and taxes = Rs.2.00
Interest on the value of stored food grains @ 10% = Rs.41.58
Value of the quantitative loss during storage Rs. 39.36.
Labour charges for loading and unloading = Rs.3.50
Storage charges/quintal = Rs.95.34
Cost of paddy/q + storage charges/q = Rs. 511.13
Selling price after storage = Rs. 78.82
Net return from storage = Rs.17.59
Per centage margin from storage = 0.034.
Paddy costs and benefits of various storage practices
Methods of Storage
Cost of Storage per
quintal for no of months of storage
Cost of storage per
quintal for one month of storage
Gross returns per
quintal for no. of months of storage
Gross returns/q for
one month of storage
Cost benefit ratio
for one quintal for one month storage
The stored grain are chiefly subjected to attack of insects,
rats and micro-organisms.
The insects feed on grains causing heating and deterioration
in stored produce.
Rats cause considerable damage and spoil the grain more than
their need by way of food contamination.
Micro-organisms like fungi, bacteria etc., are responsible for maximum
spoilage of food grains in storage and bring about heating, off odour,
discoloration, loss of nutritive value and change of palatability.
Most of the stored grain insect pests have a high rate of multiplication
and within one season they may destroy 10 - 15 % of the grain and contaminate
the rest with undesirable odours and flavours.
The following are the insect pests to cause damage the rice during
storage.
InsectPest and Damages
Rice weevil (Sitophilus oryzae Linn)
Both the grubs and adults bore into the grain and feed inside.
Lesser grain borer (Rhizopertha dominica fabr)
The grubs and adults cause serious damage by feeding inside the grain.
It is a pest of unhusked paddy.
Khapra beetle( Trogoderma granarium everds):
The grub eats the grain near the embryo or another weak point and
from their it proceeds inwards.
Rice moth (Corcyra cephalonica stain)
It is primarily pest of rice.
The larva(caterpillar) damage the grains of rice by feeding under
silken webs.
In case of severe infestation the entire stock of grain may be converted
into a webbed mass and ultimately a characteristic bad smell develops
resulting in grains unfit for human consumption.
Angoumos grain moth (Sitotroga cerealella oliver)
The larva (caterpillar) feed on internal content of grain and pupates
inside of the grain.
It inflicts severe damage to unhusked paddy.
Preventive Measures
Dry the grain properly before storing.
Store grain in receptacles or godowns.
Disinfect old gunny bags by dipping then into 0.1 % Malathion 50 EC
suspension (2 ml/lit of water) for 10 min and drying them in shade before
filling with grains.
Disinfect empty godowns by spraying 0.5 % Malathion suspension (10
ml/lit of water) on floors, walls and ceilings.
Alternatively disinfectant godowns either with 25 tablets Aluminum
phosphide or 35 lit of EDCT mixture for 1000 m3, empty space before
storing grain.
Mix Malathion 5 % dust @ 2.5 kg/ton i.e.,2.5 gm/kg of grain meant
for seed purpose.
In the stores the paddy bags should be stacked on elevated structures
(dunnage) to avoid direct contact of bags with the floor and for providing
aeration.
Care to be taken that the bag should not touch the walls to prevent
the absorption of moisture and also hiding place for rats.
Curative Measures
Fumigate the infected products with aluminum phosphide tablets @ 1
tablet / metric ton or 25 tablets for 1000 m3 space with exposure period
of 7 days.
Alternatively EDCT mixture @ 1 lit for 2 metric tons of grain or 35
lit / 100 cubic Mts. space with exposure period of 4 days.
For small scale fumigation use EDB @ 3 ml/quintal of grain with exposure
period of 4 days.
Precautions To Be Taken While Fumigation
The fumigant should be used only in air tight stores or under tarpaulin
in the open by specially trained persons, because the fumigants are
deadly poisonous.
Aluminum phosphide should not be used in living quarters.
Grain stored in metal bins may also get infested if not treated with
malathion.
They should also be fumigated.
Do not mix DDT/BHC dust even with the seed intended for sowing.
Storage fungi primarily Aspergillus and Pencillium spp occur almost
universally and attack seed stored at relative humidity of 65 - 100
%.
When seed moisture content or atmospheric relative humidity is high,
storage fungi grow rapidly and may damage seed and may cause heating.
To prevent fungal diseases seed with less than 14 % moisture content
should be stored in air tight godowns.
Control Of Rats During Storage Of Grain
Avoid thrash and unwanted materials near about the storage structures.
Fix Zinc sheets at the bottom of the wooden doors to prevent the entry
of rats into the godowns.
Block all drainage holes with wire mesh and once the rats enter into
the godown, they should be controlled by rat traps.
Organize periodical baiting with Zinc phosphide or Warfarin.
Status of storage pests
Pest control is aided by block stacking, adequate aeration and maintenance
of good hygiene.
Pesticides are used for protective and control treatments.
For protective treatments against insects, either malathion, DDVP
or pyrethrum are used for control.
Fumigation is carried out with either aluminium phosphide ethylene
dibromide or methyl bromide.
Anti-coagulants are used against rodents.
The recommended pesticide schedule for storagepests is given
below
Rice
In
Different
Bran
Name of the Pest
Paddy
Milled Raw rice
Milled Boiled Rice
Brokens
Bran
INSECTS
Rhyzopertha dominica Fab
*
+
0
+
0
Sitophilus oryzae Linn
+
*
+
*
0
Trogoderma granarium EV
0
*
*
*
0
Sitotraga cerealella Oliv
*
0
0
0
0
Corcyra cephalonica St
0
*
0
*
*
Cadra cautella Walker
0
*
0
*
*
Plodia interpunctella Hub
0
+
0
+
+
Tribolium castaneum Herb
0
+
+
*
*
Latheticus oryzae wat
0
+
*
*
*
Oryzaephilus surinamensis Linn
0
*
*
*
*
Oryzaephilus surinamensis Linn
0
*
*
*
*
Alphitobius piceus Oliv
0
0
0
*
*
RODENTS
Rattus Rattus Linn
*
*
+
*
*
`Rattus norvegicus Berk
+
+
+
*
*
Mus musculus Linn
+
*
+
*
*
BIRDS
`Sparrows
*
*
+
*
0
Pigeons
*
*
+
*
0
Crows
*
0
0
0
0
Note: O - insignificant
+ - minor * - major
Malathion - 50 per cent E.C. Premium grade.
Used as a spray (dilution 1:100 and 3 litres of dilute material for
every 100 m2) for protection of all rice products once in 15-20 days.
Pyrethrum - 2.5 per cent Pyrethrum, E.C. used as a spray (dilution
same a Malathion) for protection of all rice products, once or twice
a week, as required.
DDVP - 100 per cent E.c. used as a spray (dilution 1:300 and 3 litres
for every 100 m2) for control of surface and winged infestation.
Aluminium phosphide - Solid tablets of 3g each. Used as a fumigant
for control of infestation, in all rice products.
Dosage - 6 g/tonne under airtight covers and 43 g/m3 for sheds with
an exposure period of one week.
Ethylene dibromide - Liquid.
Used as a fumigant only for rice and brokens when control of infestation
is necessary.
Only used for shed fumigation at the rate of 22 g/m3 with an exposure
of one week.
Methyl bromide - Liquid. Used as a fumigant only for rice and brokens
when control of infestation is necessary.
Only used for shed fumigation at the rate of 22 g/m3 with an exposure
of 48 hours.
Warfarin - This is an anti-coagulant used for rat control.
It is used at 5 per cent level with any attractive edible material.
About 10-15 days continuous baiting is necessary to wipe out the rat
population.
Where mice are present the period may have to be extended to 20 days.
It is necessary that pest control measures are used by trained operators.
Full attention has to be paid to precautionary measures including
use of antidotes.
Mixing of pesticides with food grains is not advisable in view of
the consequent hazards.
Residue tolerance for the above pesticides as far as rice and other
products are concerned have been fixed under the Pure Food Act of Government
of India.
The treatments have to ensure that these residue limits are not exceeded.
Pest control agencies undertake control work under expert supervision
and ensure meeting relevant requirements.
Storage
