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.
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 . li> 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 weather 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
APAU 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. T
he 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
nterest 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.
Insect Pest 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 during 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.
Rat Control in Storage
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:
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
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) protection 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
