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                                        Rice (dhan)
Rice (dhan) a CEREAL food plant, Oryza sativa, of the grass family Gramineae, extensively
cultivated in warm climates, especially in East Asia, producing seeds that are cooked and
used as food. The word Ouliz of the Ningpo dialect of old Chinese language became Oruz in
Arabic and Oryza in Greek languages which were changed to Ritz and Rice. Origins of the
words dhan, dhanya is not known. Rice, the staple cereal of millions of people, is a crop of
antiquity. Under the patronage of the kings of China and Japan rice began to be cultivated
about 10,000 years ago. This crop has a wider adaptability and grows from North Korea to
South Australia and from sea level to an elevation of about 2,600 m (Jumla, Nepal).


Rice     is   cultivated   in    Bangladesh
throughout the year as Aush, Aman or
Boro. Aman (broadcast and transplanted)
is generally cultivated in December-
January, Boro in March-May, and Aus in
July-August cropping seasons. Among
these croppings transplanted Aman is
most important and occupies about
                                              Ripe paddy
46.30% of the rice cultivated land.


The rest 26.85, 17.59 and 9.26 percent of the land is occupied by Boro, Aus and sown Aman
respectively. Transplanted Aman is grown throughout Bangladesh and sown or broadcast
Aman is grown mostly in the south and southeastern part of the country. Aus is cultivated
scatteredly in most of the districts.

About 40 percent of the world's population derives most of their calories from rice. Almost
90 percent of the population of Bangladesh, Myanmar, Sri Lanka, Vietnam and Kampuchea
are rice eaters.
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Rice is interwoven with Bangali culture. It is the symbol of wealth. The Food Department of
the Government of Bangladesh recommends 410 gms of rice/head/day. In 1997-98,
Bangladesh produced about 19 million metric tons of rice. This was 15% less than the need.
Table shows the statistics of rice production in Bangladesh during 1997-98. Aman tops the
position, followed by Boro and Aus, irrespective of area and production. Though covering
55.65% of total area, high yielding varieties (HYV) produced 73.59% of total yield. From a
minor position, Boro has stepped up to the second place. In 1995-96 agricultural GDP was
30% (at current price), and crop sector had an 18% share. Rice alone-shared 13% of
agriculture and 72% of the crop sector's GDP. Rice covers about 70 percent of the total
annual cropped area. It is grown throughout the year and provides employment for 75 percent
of the total labour force in the rural areas of Bangladesh.

Husked dhan is chaul or chal. Cooked chal is bhat. Polao, morog-polao, biriani, tehari, etc
are special dishes of aromatic small grains cooked with chicken, beef, mutton, butter oil and
spices. Over cooked rice mixed with pulse is khichudi. Pulse and vegetables added to
khichudi increase its protein efficiency ratio and therefore is more nutritious.

Rice Plant Paddy is the fruit cum seed. When the seed germinates the emerging plumule and
radical develop respectively into a stem and adventitious roots. The stem has nodes and
internodes. The leaf originates from a nodal bud and consists of a sheath and a long blade.
The last leaf is the flag leaf which bears the last internode called rice panicle. This contains
florets (Spikelets); usually each flower produces one paddy.


Basal nodes produce branches called tillers,
which also bear panicles. HYVs produce
more tillers and grains, giving higher yields
in comparison to the traditional varieties.

Each of the rice groups of Bangladesh has
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distinct     physio-genetical     characteristics. Rice planting
Rayda, the progenitor of the Bangladeshi
rice groups, is now an endangered group.


Each rice group has many varieties and land-races which are called germplasms.
BANGLADESH RICE RESEARCH INSTITUTE               (BRRI) has about 5,000 such germplasms in their
gene bank for use.

Different forms of processed rice and rice products are consumed in Bangladesh. These are
as follows: atap milled rice from sun-dried paddy; shiddhya-chaul rice milled from parboiled
paddy; cheeda, khoi and moodi are flattened, puffed and popped products from paddy.

Rice grain or starch is used in the manufacture of cosmetics, cigarette paper and alcoholic
beverages. Rice bran produces an edible oil and vitamins and is also used as cattle and
poultry feed. Silica rich rice husk is used as an abrasive for polishing gun-barrels. Pure silica
extracted from rice husk is used to produce microchips of electronics. Rice straw is
extensively used as cattle fodder, for thatching roofs, and for the manufacture of straw
boards.

Table Area and production of rice in Bangladesh (1997-98)


                     Area     mill %     of   total Production (clean                 Mean yield /ha
Rice crops                                                               % of total
                     ha           area             rice) million m ton                (m ton)

Aux                  1.56         15.20            1.87                  9.91         1.20

(HYV Aux)            (0.49)       (4.78)           (0.87)                (4.61)       (1.78)

Aman                 5.81         56.63            8.85                  46.92        1.52

(HYV Aman)           (2.55)       (24.86)          (5.21)                (27.62)      (2.04)

Boro                 2.89         28.17            8.14                  43.16        2.82
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(HYV Boro)          (2.67)      (26.02)       (7.80)            (41.36)           (2.92)

Total               10.26       ---           18.86             ---               ---

(Total HYV)         (5.71)      (55.65)       (13.88)           ---               ---


Rice is rich in carbohydrate. The protein content is about 8.5 percent. Rice does not have C
and A vitamins. The thiamin and riboflavin contents are 0.27 and 0.12 micrograms
respectively.

Taxonomically, rice belongs to the tribe Oryzeae of the family Gramineae. Either O. perennis
or O. rufipogon might have been the parent of Oryza sativa (the Asiatic rice) which includes
all the present cultivated rice. The 2n number of chromosomes of rice is 24. The wild rice O.
officinalis is also found in Bangladesh. Another wild rice locally called Uri-Dhan is found in
the saline estuarine coastal areas. The previous name Oryza coarctata has been changed to
Porteresia coarctata. This wild rice is collected by coastal people and consumed as a
delicacy. It needs improvement for commercial production. [SM Hasanuzzaman]

Deepwater rice Rice grown in more than 50 cm water for one month or a longer period
during the growing season. Based on stature and depth of water, these are of two types: (i)
traditional tall, and (ii) floating rice. Traditional tall cultivars have long leaves, and are grown
at water depths of between 50 and 100 cm; floating rice is grown in 100 cm or deeper
situations. In Bangladesh most of the rice grown in low-lying areas during the monsoon
season are floating type, generally called deepwater rice, and locally known as jolidhan,
poushdhan, etc.

Deepwater rice grown in Asia is a cultiver of Oryza sativa, probably evolved from perennial
grass, Oryza rufipogon, via annual wild relative, Oryza nivara. There are more than 2,000
deepwater rice cultivars in Bangladesh and more than 6,000 in Asia. Almost all the
deepwater cultivars are strongly photo-period sensitive. Photosensitivity fixes flowering time
at a favourable point in the flooding period, enables the plant to escape the adverse effects of
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low temperature in the reproductive phase, and usually ensures crop maturity as soon as
floods have receded. The panicle is often of the awned, spreading type, and seeds are prone
to shatter. Seeds have dormancy period lasting for several weeks.




Deepwater rice


Deepwater (floating) rice has three special adaptations: (i) ability to elongate with the rise of
water levels; (ii) develop nodal tillers and roots from the upper nodes in the water; and iii) the
upward bending of the terminal part of the plant called 'kneeing' that keeps the reproductive
parts above the water as flood water subsides. Deepwater rice grows under rainfed dry land
condition for 2-4 months, before the onset of flood, when the plant produces basal tillers.
With inundation, the plant becomes an emergent macrophyte and grows in an aquatic
environment for the remaining 3-5 months of its life. Nodal roots absorb nitrogen,
phosphorous, and possibly other nutrients from floodwater. There is an increase in the
number of elongated internodes with the increase in water depths. Majority of deepwater rice
cultivars in Bangladesh is of strong elongators. Stems may reach 5-6 m in very deepwater (3-
4m) situations. Deepwater rice does not normally survive water depths greater than 4m.
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In Bangladesh, deepwater rice occupied 2.09 million ha (21% of the total rice area) in the late
1960s. The area has now shrunk to about 0.85 million ha because of cultivation of high
yielding varieties under irrigation in deepwater rice fields in the dry season (boro). At
present, 1.24 million ha remain fallow during the monsoon. Deepwater rice is usually dry
seeded in the months of March-April following the first monsoon shower. In some areas,
farmers establish deepwater rice by transplanting seedlings following the cultivation of dry
season rice. Very little fertiliser is used and weeds are effectively controlled by harrowing
and hand weeding, twice before flooding occurs. Crops mature between mid-October and
mid-December, depending on the degree of photo-period sensitivity of the cultivar. Grain
production tends to increase with the increase in biomass up to 12m tons/ha (dry weight). The
harvest index typically varies from 0.12 to 0.16 and tends to increase in shallow water
situations. Heaviest panicles are borne on the main tillers followed by basal tillers and
lightest panicles by nodal tiller. Panicle density usually varies between 50 and 120 per sq m.
Average grain yields are 2.3m tons/ha and some cultivars have the potential of producing
yields more than 3.0 m tons/ha. [Zahirul Islam]

Rice harvesting and threshing Harvesting starts soon after the crop ripens to prevent rot or
damage from weather or insects. Rice ripens in different times of the year, depending on
variety, so that harvesting of one may begin while the other is yet to reach maturity. In
Bangladesh the harvesting time of rice in different seasons are: Aus (July-August), broadcast
Aman (November-December), transplanted Aman (November-January), local boro (April-
May), and high yielding boro (May-June). Harvesting can either be done manually with the
use of hand harvesting tools, or mechanically, with the use of harvesting machines (reaper,
harvesters). In Bangladesh rice harvesting is done manually, using sickles (kanchi),
consisting of a wooden handle and a knife blade (made of mild steel), the base of which is
pushed into the wooden handle. The blade may be 20-30 cm long, having a serrated edge (15
serration per 2.5 cm, with teeth 1 mm long).
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The plants are cut with
about 50 cm of straw and
are often dried in the field.
If the threshing is to be
done later, they are piled
into    stacks    with    the
panicles placed toward the
centre to permit further
drying of the grains. The
time required to cut and lay Rice harvesting
aside the plants may be 60-
80 man-hour/ha.


Threshing is the removal or separation of grains from the panicles of the paddy stalks. Hand
beating, ox treading, or a combination of both; and use of pedal threshers are the common
methods of threshing. Foot treading is also practiced in some areas. In hand beating, small
bundles are beaten on drums, wooden logs, stones, bare ground or other hard materials.
Depending upon bundle size, variety, and physical condition of workers each bundle is
beaten 5 to 10 times in order to shatter all grains. In ox treading, bundles are initially placed
around, with panicles positioning inward or on one side of the threshing floor. Two to four
oxen are generally used in single row in tandem going around the materials being threshed. A
man always stays behind to drive the oxen, tied loosely on a pole at the centre, to walk
around the threshing floor.
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Various methods of rice threshing

In some areas, no centre pole is placed. The man behind controls the movement of the oxen.
Well off farmers sometimes use 6 or 8 oxen in double row in tandem to thresh more materials
at a time. As ox treading continues, additional bundles are spread by one or two men, who
also take care of turning and shaking the straw from time to time. This continues until all the
grains are separated from the straw. Grains are then partially cleaned and removed from the
threshing floor. In most parts of the country, ox-treading is done as a second stage threshing
after hand beating to further separate the remaining filled grain and to soften the straw to be
used for animal feeds. The time gap between the two stage of threshing operations varies up
to 3 month, depending upon the climate, availability of animals, etc. In the Aman season, it
usually extends up to 3 months because the weather is cool and dry, and because the paddy
and straw have already dried. In Boro and Aus season, however, priority is given to field
activities.
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            Rice cleaning before storing


Hand beating and foot-threshing are practiced occasionally when the straw is needed for
roofing, the yard is wet and animals are not available; when there are no facilities for ox-
treading; and there is an urgent need for food. A pedal thresher is the only mechanical
equipment used for threshing paddy.


It is a portable machine,
consisting of a strong wire-
looped cylinder, driven by
foot through a shaft liver and
a gear system. The machine
is operated by moving the
pedal up and down with one
foot while harvested stalks
are fed on the rotating
cylinder.        Grains      are
separated from the panicles Rice drying before storing
with the action of protruding
wire loops in the rotating
cylinder.


Generally, one helper picks a handful of harvested stalks from the pile, gives them to the
operator who thresh while pedalling. The pedal thresher is closely associated with threshing
HYVs. In Comilla district where HYV are widely grown, almost all farmers use pedal
threshers. It is capable of being operated by women and children anytime and used indoors,
particularly during the rainy season.

Pedal threshers are also used by the farmers in the northwest region of Bangladesh,
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particularly in the Boro and Aus seasons when HYVs are widely grown. Traditional
threshing, however, is still widely practiced during the Aman season. Power threshers are
also used in some part of the country. [Md. Nurul Islam]

Rice storage Keeping harvested paddy or threshed, dried rice in appropriate places, bins,
warehouse or containers for future use and also to prevent deterioration of quality of the
grain. The purposes of rice storage are: to provide constant supply of food grain throughout
year; to retain viability of the grain for planting in the following season; to take advantages of
higher prices offered by traders; and to serve as reserve during times of food scarcity. Stored
rice appears to be more relished and hence conventionally some consumers prefer to store
rice for a certain period. Rice storage is therefore carried out by the producer, the trader, the
processor, the government and the consumer. Rice grain is generally stored from one harvest
season to the next for a maximum of one year. However, crop surpluses or government
policies might require that the grain be stored for extended periods.

Significant losses in quantity and quality of stored rice occur through the activities of
microorganisms, insects, mites, and rodents. Traditional and inefficient methods of
harvesting, threshing, drying, storage and processing causes about 13% postharvest loss of
the food grain, which is estimated to be about 3.51 million m tons per year. Deterioration of
stored rice arises from a variety of causes. However, such losses can be reduced by control of
the two most important variables such as, moisture and temperature. Since freshly harvested
rice has moisture content of 20% or more, the grain must be dried before storage. At 14%,
rice can be stored safely for two to three months. For longer storage, the rice should be dried
to moisture content of about 12%.

Storage systems Like all other food grains, rice is stored principally by two methods. These
are storage in gunny bags and loose in bulk storage. Although bulk storage facilities in
traditional bins and some modern silos are in use in Bangladesh, rice is frequently stored in
bags. The bag storage method is more expensive than bulk storage because it requires the
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purchase of gunny bags; it is more labour intensive and requires more storage space per unit
weight of rice. Regardless of the methods of storage, the grain must be dry and clean and
must be protected from weather and pests.

Traditional storage Most rice grains produced in the country are stored in traditional storage
structures at farmers level; these account for 70-80% of the total produce. The most widely
used rice storage structures in the rural areas of Bangladesh are different types of traditional
bins which are used for bulk storage of food grains. These include various types of earthen
wares, and bins made of plant materials, especially bamboo.




Traditional methods of rice storage


Earthen containers Various types of earthenwares made of burnt or unburnt clay of different
capacities are extensively used for storage of foodgrains, particularly of seed paddy.
Containers made of burnt clay are locally known as jala, matki and kola, and are spherical or
oval in shape, having a small opening at the top for pouring grains into the vessel. Earthen
covers are used for these containers. The capacity of jala varies from 50 kg to 300 kg, while
the capacity of Kola ranges from 20 kg to 150 kg. Mud bins locally called kuthi, are made of
unburnt clay, and are usually rectangular or circular in shape. The clay is mixed with paddy
husk, cow dung and straw. The fibrous materials are used as binder with clay to prevent any
cracks on the wall. The mouth of the container may also be sealed or plastered with mud after
the vessel is filled with grains. Such a storage may have a small opening at the lower part
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through which the stored grains can be taken out at the time of need without opening the
mouth lid. A kuthi may also have several chambers inside for storing different varieties of
rice or other foodgrains separately. Such structures have capacities ranging from 200 kg to
800 kg. The earthen containers are usually placed on the ground or on a platform inside the
house.

Bamboo bins These are made of bamboo mats, splits or wattles. The different types of
bamboo bins are locally known as dole, ber and dhari, depending on the nature of the
construction materials used and the shape of the containers. Bamboo bins are most popular of
the storage structures used by farmers. These storage containers are usually located inside a
dwelling house and placed on a bamboo frame or on wooden platforms raised 0.5 m to 1.0 m
above ground level for protection from ground moisture, rodents and insects. The Dole is
usually made of bamboo mats or wattles of stems of Saccharum anundinaceum, locally
known as nal. The mats or wattles are continuously woven to give the cylindrical or oval
shape of the dole which is open at the top. Sometimes both the inner and outer surface of the
dole are plastered with cowdung or with a mixture of cowdung and mud. Its usual capacity
ranges from 200 kg to 800 kg.

Ber is a spherical or oval shaped container, made of bamboo splits, opening both at the top
and the bottom. A mixture of mud and cowdung is plastered on the inside surface of the ber.
A rope, made of straw, is placed at the base of the ber before filling it with grains. The
storage capacity of the type of container ranges from 600 kg to 1,600 kg. Dhari is a
cylindrical container made of several (2-5) bamboo mats joined together to give it its usual
shape and is open both at the top and bottom ends. At every junctions of the dhari, two
bamboo splits of desirable strength are fastened by wires to make it cylindrical in shape.
Before it is filled with grains, a straw-made rope is placed around the base of the dhari. Its
storage capacity ranges from 800 kg to 3,000 kg.

Store house The store house, locally called gola ghar, is a very common structure in rural
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Bangladesh built for bulk storage of rice. It is usually constructed in the premises of the
house and has a thatched roof and a platform raised 0.5 m to 1.0 m above ground level. The
walls are made of bamboo wattles plastered with a mixture of cowdung and mud. Sometimes
a gola ghar has several chambers, each with a separate door to store different varieties of
paddy or foodgrains separately. The capacity ranges from 1,000 kg to 10,000 kg.

Bag storage In addition to above traditional storage structures, many farmers store their rice
in gunny (jute) bags. The capacity of each bag varies from 80 kg to 100 kg. The filled bags
are piled on a platform in a house built with thatched roofing. Such stores may often be a part
of the dwelling house.

Government storage These storage facilities are elaborations of traditional methods, but are
constructed with modern materials. There are of two main types: warehouse, and silo bins.
Such structures are used in commercial grain storage systems and involve the storage of large
quantities of foodgrains by commercial traders and government departments having adequate
economic and technical support.

Warehouse In Bangladesh the most common commercial rice storage method is bag storage.
This is utilized mainly by rice traders in different types of buildings, made either of bricks or
corrugated iron sheets or/and mud and wattle, with or without plastered walls, and with an
earthen or cement floor. The warehouses are known as Conventional Godowns. Such
godowns are also maintained by government departments. The bagged foodgrain storage
systems are named as Local Storage Depot (LSD) and Central Storage Depot (CSD). There
are 9 CSDs and 620 LSDs scattered all over the country with storage capacities of about 4
lakh 30 thousand m tons and 11 lakh 50 thousand m tons respectively. Various foodgrains
especially paddy, milled rice, and wheat are usually stored by the government in these
storage systems. The LSDs are located in the vicinity of Union, Upazila and District
headquarters, while the CSDs are located at larger towns/cities and ports.
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In Bangladesh, one of the major disadvantages of the bagged storage system is that the
readsorption of moisture takes place during the humid wet season, especially in the outer
layers of bags. This accelerates biological activity in the grains and results in deterioration
and loss of the product. In the hot dry season, when roof and wall surface temperatures are
extremely high, foodgrains stacked within one meter of the roof or close to walls become hot.
This causes relocation of moisture which results in deterioration of the grain during storage.

Silo Storage A silo is a storage facility with provision for mechanical handling of foodgrains.
All silos in Bangladesh are operated by the government. The country has 9 silo storage
facilities located at regional levels, particularly in port areas and places where road and
transportation facilities are well developed. The total storage capacity of these silo units is
about 3 lakh 60 thousand m tons. A silo installation is also known as an 'Elevator', because it
is equipped with elevators. [M Shams-Ud-Din]

Diseases All the cultivated varieties of rice suffer from several diseases. Of these, viral,
bacterial, fungal, and nematode-borne diseases are mostly prevalent between June and
December.

Virus and Mycoplasma diseases- Tungro was first recorded in Bangladesh in 1966, and is
reported as the most damaging viral disease of Bangladesh. Stunting of the plant along with
twisting of the leaves, reduced tillering, delayed flowering etc are the distinguishing features
of the disease. The disease is transmitted by leafhoppers, Nephotettix virescens, N.
nigropictus, and Recilia (=Inazuma) dorsalis.

Yellow dwarf is a minor disease in Bangladesh. Symptomatically, the leaves, particularly the
young and newly emerged ones show general yellowing which follows severe stunting,
production of fewer panicles and chaffy grains. The organism is transmitted by insect vector
Nilaparvata lugens.

Grassy stunt disease caused by phytoplasma shows severe stunting symptoms, and excessive
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tillering, along with short narrow, light green, or pale yellow erect leaves. Rusty spots are
seen on the leaves, often accompanied by chlorosis.

Bacterial diseases- Bacterial blight/Bacterial leaf blight In Bangladesh the disease was first
noticed in 1966. The disease is caused by a rod shaped gram-negative bacteria, Xanthomonas
campestris pv oryzae. In transplanted rice the disease normally appears after six weeks of
planting. In the flag leaf, the symptoms are frequently visible. The drying of the leaf usually
originates from the tip and extends downwards from both side of the leaf blade and may
reach upto the leaf sheath depending on the variety.

Bacterial leaf streak Is caused by Xanthomonas campestris pv. oryzicola. Symptoms are
restricted in the leaf. In case of severity of the disease the entire leaf becomes yellow or
brownish-red. The disease is seed borne, and the pathogen may overwinter in straw and
stubbles.

Fungal diseases As many as 19 fungal diseases have been recorded from Bangladesh. The
major and important diseases are the sheath blight, brown spot, leaf scald, sheath rot, blast,
bakanae, and stem rot, stack burn, and bunt.

Sheath blight caused by Rhizoctonia solani normally remains restricted to the lower leaf
sheaths of older leaves, and no visual damage is noticed.

Brown spot disease, also known as 'sesame spot' is caused by Bipolaris oryzae. The disease is
prevalent all over Bangladesh. It is said that the Bengal famine of 1942, in the then undivided
India was due to crop failure caused largely by B. oryzae.

Sheath rot caused by Sarocladium oryzae first described from Formosa in 1922, is now a
common disease in most of the potential HYV of rice in Bangladesh. Symptoms of the
disease appear at the maturing stage. Typically the lesions start developing on the flag leaf
sheath as oblong or irregular spots with brown margins and greenish to greyish centres.
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Stem rot disease caused by Sclerotium oryzae was first reported from Noakhali in 1913. The
initial symptoms appear as irregular water-soaked marks on the leaf sheath over the culm at
the lower internode, at above the water level, usually a few weeks before emergence of the
panicle. The infected areas soon turn black and enlage in size.




       Rice diseases: Stem rot (left); Brown spot (right)

Nematode diseases In Bangladesh five diseases caused by nematodes have been reported. Of
these Ufra, Root Knot, and White Tip are most important.

Ufra is locally known as ' dak pora' or 'thore morah'. The causal organism is Ditylenchus
angustus, a minute, thread-like ectoparasitic nematode. It survives and multiplies in the living
host rice. It is a destructive disease of deep-water rice in Bangladesh, first recorded by Butler
in 1913 in Noakhali. Panicles fail to emerge in case of early infection before heading.

Root knot disease is caused by Meloidogyne species. The nematode produces knots in root
systems. Severely attacked plants show stunted growth.

White tip disease caused by Aphelenchoides besseyii has been reported to affect deep-water
17



rice. The nematode attacks roots, resulting in root discolouration and retardation of growth.
[Abul Khair]

Pests Drought, storm, flood and excessive rain often affect rice cultivation. In addition to the
natural calamities, a large number of invertebrate pests, including nematodes, snails,
crustaceans, and insects, and several vertebrate pests such as birds and rodents attack rice
plant at all its stages of growth. It is estimated that 10-15 percent yield losses occur due to
insect damage alone.

Nematodes In Bangladesh the most injurious is the rice stem nematode, Ditylenchus
angustus. It is about 1 mm in length, thread like with both ends pointed. The pest feeds
ectoparasitically on the tissues of leaves and sheaths, growing buds, and ear primordia. The
collective symptoms are known as Ufra disease. Other nematodes that have been recorded in
Bangladesh include the rice leaf nematode, Aphelenchoides besseyii; root knot nematode
Meloidogyne incognata; rice cyst nematode, Heterodera oryzae; rice root nematode,
Hirschmanniella oryzae; and stunt nematodes, Tylenchorhynchus species.

Snails Among snail species, Ampullaria attack rice plants at the seedling stage. In most cases
the affected plants die.

Crabs Several species of crabs of the families Gecarinidae and Pontamonidae damage rice
plants. They usually feed on the seedlings of seedbeds at night. Often, the crabs puncture the
bunds of the irrigation system causing inconvenience in the supply of water.

Insects Insect pests constitute one of the principal causes of low yields of rice in Bangladesh.
Prior to 1972 only 76 species of rice insects were recorded in Bangladesh. By 1979 another
83 species were added making the total 159. These insect pests belong to 7 orders and 44
families (Table), the majority being members of the order Lepidoptera (58 species) and
Homoptera (44 species).
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                                                                 Table Families and species of
                                                                 insect pests of rice under
Order                 No. of families        No. of species
                                                                 different orders
Coleoptera            8                      20

Diptera               4                      4

Hemiptera             3                      10

Homoptera             12                     44

Lepidoptera           9                      58

Orthoptera            5                      17

Thysanoptera          3                      6

Total                 44                     159

Source Nine Years of Entomology Division, BRRI, 1983


There are several leaf feeders of rice which destroy crops. These include the swarming
caterpillar, rice ear-cutting caterpillar, RICE HISPA, grasshoppers. The rice leaf folder and rice
case-worm also infest leaves of young plants and under favourable environmental conditions
may inflict considerable damage to growing crops. A list of some common rice pests of
Bangladesh is given in the following Table.

Table Common insect pests of rice of Bangladesh


Common name                       Scientific name               Order: Family

Yellow stem borer                 Scirpophaga incertulas        Lepidoptera: Pyralidae

Dark-headed stem borer            Chilo polychrysa              Lepidoptera: Pyralidae

Pink stem borer                   Sesamia inferens              Lepidoptera: Noctuidae

Gall midge                        Orseolia oryzae               Diptera: Cecidomyiidae
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Leaf folder                Cnaphalocrocis medinalis   Lepidoptera: Pyralidae
                           Marasmia patnalis          Lepidoptera: Pyralidae

Whorl maggot               Hydrellia philippina       Diptera: Ephydridae

Caseworm/leaf roller       Nymphula depunctalis       Lepidoptera: Pyralidae
                           N. fluctuosalis            Lepidoptera: Pyralidae
                           N. foedalis                Lepidoptera: Pyralidae

Swarming caterpillar       Spodoptera mauritia        Lepidoptera: Noctuidae
                           S. pecten

Rice hispa                 Dicladispa armigera        Coleoptera: Chrysomelidae

Leaf beetle                Cassida nigriventris       Coleoptera: Chrysomelidae
                           Haltica foveicollis        Coleoptera: Chrysomelidae

Grasshopper                Oxya velox                 Orthoptera: Acrididae
                           O. hyla                    Orthoptera: Acrididae

Brown planthopper          Nilaparvata lugens         Homoptera: Delphacidae

White-backed planthopper   Sogatella furcifera        Homoptera: Delphacidae

Rice mealybug              Brevennia rehi             Homoptera: Pseudococcidae

Green leafhopper           Nephotettix virescens      Homoptera: Cicadellidae
                           N. nigropictus             Homoptera: Cicadellidae

White rice leafhopper      Tettigella spectra         Homoptera: Cicadellidae
                           Kolla mimica               Homoptera: Cicadellidae

Orange-headed leafhopper   Thaia oryzivora            Homoptera: Cicadellidae

Zigzaz leafhopper          Inazuma dorsals            Homoptera: Cicadellidae

Thrips                     Frankliniella intonsa      Thysanoptera: Thripidae

Rice bug                   Leptocorisa acuta          Hemiptera: Coreidae
                           L. oratorius               Hemiptera: Coreidae

Rice stink bug             Eysarcoris ventralis       Hemiptera: Pentatomidae
20




Rich ear-cutting caterpillar   Mythimna separata              Lepidoptera: Noctuidae


About 85 species of parasites of rice insects have been recorded in Bangladesh. Of these, 14
species under 5 families belong to Diptera, and 71 species under 14 families, are
hymenopteran parasites. Most species are larval parasites and attack in particular the species
of STEM BORERs, ear-cutting caterpillar, swarming caterpillar, rice hispa, green leafhopper,
and leaf roller.

For management of rice pests, growers mostly use chemical insecticides. Recently, efforts
have been made by the Department of Agricultural Extension, Government of Bangladesh, to
motivate farmers through training and demonstration for adoption of integrated pest
management for the control of rice pests.




Collection from The Banglapedia.

Collector:
Abdur Rab (forhad)
Department of Public Administration.
Jahangirnagar University
Dhaka, Bangladesh.
Email: abdurrab79@yahoo.com

				
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