Common Rice diseases, it's symptoms and control measure

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2. Topic: Common Rice
Disease in Bangladesh
Prepared by
Md : Aminul Haque
aminulparvez85@gmail.com
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3. Introduction
Rice Bacterial Diseases
 Rice Fungal Diseases
Rice Viral Diseases
Rice Nematodes Diseases
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4. Bangladesh is 4th rice producing country
in the world.
Rice is cultivated in Bangladesh
throughout the year as Aush, Aman & Boro
Rice is grown on about 10.5 million
hectares
 Total Rice production 25.27 million MTT.
Every year 13% yield reduced due to
disease & disease.
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5. In Bangladesh, 31 rice diseases have
been so far identified of which ten are
considered as major.
 Sheath blight, blast, bakanae etc. are the
major rice diseases in Bangladesh.
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6. Bacterial blight
Bacterial leaf streak
Foot rot
Grain rot
Pecky rice (kernel spotting)
Sheath brown rot
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7.  Bacterial blight (
Xanthomonas oryzae )
The disease favors temperatures
at 25−34°C, with relative humidity
above 70%.
 Symptoms :
Infected leaves turn grayish
green and roll up.
As the disease progresses, the
leaves turn yellow to straw-
colored and wilt, leading whole
seedlings to dry up and die.
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9.  Bacterial blight
 Management: Yield loss due to bacterial blight
can be as much as 70% when susceptible
varieties are grown, in environments favorable to
the disease.
 Use balanced amounts of plant nutrients,
especially nitrogen.
 The most common and most effective
management practice is to use of resistant
varieties like BR1, BR2, BR4, BR5, BR6,
BR27, BR33, BR37, BR38, BR40 BR41, BR42,
BR44, BR46
 Ensure good drainage of fields (in conventionally
flooded crops) and nurseries. 9

10.  Management:
 Allow fallow fields to dry in order to suppress disease
agents in the soil and plant residues.
 Keep fields clean. Remove weed hosts and plow
under rice stubble, straw, rice ratoons and volunteer
seedlings, which can serve as hosts of bacteria.
 Seed treatment with bleaching powder (100 grams
per liter) and 2 percent zinc sulphate.
 Other chemicals such as copper compounds and
antibiotics have not been proven effective.
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11.  Bacterial leaf
streak(Xanthomonas oryzae)
 Bacterial leaf streak occurs in
areas with high temperature
and high humidity.
 It is transmitted through seeds
and infected stubbles to the
next planting season. It can
occur in fields
where oryzae pv. oryzicola bact
eria is present on leaves, in the
water, or in the debris left after
harvest.
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12. Bacterial leaf streak (Xanthomonas
oryzae)
 Symptoms:
 Symptoms initially appear as small,
water-soaked, linear lesions between
leaf veins. These streaks are initially
dark green and later become light
brown to yellowish gray.
 The lesions are translucent when held
against the light.
 Entire leaves may become brown and
die when the disease is very severe.
 Under humid conditions, yellow
droplets of bacterial ooze, which
contain masses of bacterial cells, may
be observed on the surface of leaves.
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13.  Bacterial leaf streak(Xanthomonas
oryzae)
 Management
 Use balanced amounts of plant nutrients,
especially nitrogen.
 The most common and most effective
management practice is to use of resistant
varieties like BR1, BR2, BR4, BR5, BR6,
BR27, BR33, BR37, BR38, BR40 BR41,
BR42, BR44, BR46
 Ensure good drainage of fields (in
conventionally flooded crops) and nurseries.
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14.  Bacterial leaf streak(Xanthomonas
oryzae)
 Management
 Seed treatment with bleaching powder (100
grams per liter) and 2 percent zinc sulphate.
 Other chemicals such as copper compounds
and antibiotics have not been proven
effective.
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15.  Foot rot (Fusarium moniliforme)
Symptoms: Diseased plants appear
abnormally elongated, thin, and yellow
green compared to with other plants.
Diseased plants may be distributed
irregularly in an infected field. In the
seedbed, heavily infected seedlings with
necrotic lesions on roots die before or
after transplanting.
White powdery growths of conidiophores
can be seen over the lower regions of
the diseased plants.
Diseased plants bear few tillers and their
leaves dry up quickly. The diseased
plants survive but bear empty panicles.
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17.  Foot rot (Erwinia chrysanthemi)
 Management: Management
 Pre and post-harvest measures should be
taken into account for prevention of grain
discolouration.
 Spray the crop at boot leaf stage and at 50%
flowering with Carbendazim + Mancozeb (1:1)
@ 0.2%.
 Store the grains with 13.5-14% moisture
content
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18.  Sheath brown rot
 Sheath rot is caused
by Sarocladium oryzae
 Symptoms: The typical
sheath rot lesion starts at the
uppermost leaf sheath
enclosing the young panicles.
It appears oblong or as
irregular spot with dark
reddish, brown margins, and
gray center or brownish gray
throughout.
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20.  Sheath brown rot( Sarocladium oryzae )
 Management:
 Sheath rot is a seed-borne disease, use healthy seeds.
 Minimize insect infestation in rice field. Insects cause injuries
to the plants that allow the fungi to enter the plant and cause
infection.
 The fungi survive on rice crop residue after harvest and can
cause infection in following seasons. Remove infected
stubbles after harvest.
 Use optimum plant spacing. Sow three plants per hill at 20 cm
row spacing.
 Apply potash at tillering stage.
 Apply foliar spray of calcium sulfate and zinc sulfate.
 Apply a seed treatment fungicide like carbendazim,
edifenphos, or mancozeb as seed treatment and foliar
spraying at booting stage.
 Apply a foliar fungicide like benomyl and copper oxychloride
as foliar sprays.
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21.  Blast (leaf, neck [rotten neck], nodal and
collar)
 Brown spot
 Sheath blight
 Narrow brown leaf spot
 Crown sheath rot
 Downy mildew
 Eyespot
 False smut
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22.  Kernel smut
 Leaf smut
 Leaf scald
 Root rots
 Seedling blight
 Sheath blight
 Sheath rot
 Sheath spot
 Stem rot
 Water-mold (seed-rot and seedling disease)
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23.  Blast (leaf, neck, nodal and collar)
 Pathogen :Magnaporthe oryzae
 Symptoms
 The symptoms can be found on leaves, leaf collars, necks,
panicles, and seeds.
 A recent report shows that even roots can become infected.
 Rice leaves. The most common and diagnostic symptom,
diamond shaped lesions of rice blast occur on the leaves. brown
to dark brown in color.
 Rice collars. Necrosis on collars. Collar infections can kill the
entire leaf and may extend a few millimeters into and around
the sheath.
 Rice necks and panicles. Infection of the necks can be very
destructive, causing failure of the seeds to fill or causing the
entire panicle to fall over as if rotted.
 Rice seeds. Symptoms of rice blast on seeds are brown spots,
blotches and occasionally the classic diamond-shaped lesion
often seen on leaves.
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24.  Blast(Magnaporthe oryzae )
 Management:
 1. Use of resistant/moderately resistant varieties like
 BR3, BR4, BR9, BR10, BR11and BR12,
 2. Crop rotation
 3. Proper fertilization. Overuse of nitrogen fertilizers, increases the amount
of rice blast.
 4. maintaining a proper flood level for the rice to grow or regular irrigation
apply
 5. Adjustment of planting time to avoid blast favorable weather condition

 6. using high quality and disease-free seed. uses seed treatments to
prevent infection of the seedlings after germination. E.g. vitavex
 7. Uses one or two applications of fungicides to the foliage to protect the
panicles when they are emerging from the boot.
 Spray Hinosan @ 800ml in 1000 ml water/ha or Benlate @ 2.25 kg/1000L
water/ha.
 Systemic fungicides like triazoles and strobilurins can be used judiciously for
control to control blast. A fungicide application at heading can be effective in
controlling the disease
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25.  Brown spot(Helminthosporium
oryzae )
 Symptoms
 Typical spots on the leaves are
oval, about the size and shape of
sesame seeds.
 They are relatively uniform and
fairly evenly distributed over the
leaf surface.
 Young spots are small, circular
(0.05 to 0.10mm in diameter) and
usually dark brown.
 Most spots have a light-yellow halo
around their margins.
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26. Brown spot
Management Options
Since the disease is known to be
associated with soil deficient in
nutrients, proper fertilization, good
water management and soil amendment
are suggested as management option
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27.  Narrow Brown Spot
 Causal organism :
Cercospora oryzae
 Symptoms:
 The characteristic symptoms of
the disease are usually
observed during the late growth
stages and are characterized by
the presence of short, linear,
brown lesions mainly on the
leaves (although it may also
occur on leaf sheaths, pedicels,
and glumes).
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28. Narrow Brown Spot
Management
Foliar fungicides such as mancozeb,
benomyl, propiconazole, and iprodione
effectively suppress this disease and
may be economical if other diseases
are also controlled along with narrow
brown spot.
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29.  Rice Sheath
Blight(Rhizoctonia solani)
Symptoms:
 Initial lesions are small,
ellipsoidal or ovoid, greenish-
gray and water-soaked and
usually develop near the water
line in lowland fields
 Older lesions are elliptical or
ovoid with a grayish white
center and light brown to dark
brown margin.
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30. Rice Sheath Blight
(Rhizoctonia solani)
Symptoms:
Lesions may reach the
uppermost leaf under
favorable conditions
Lesions may coalesce
forming bigger lesions with
irregular outline and may
cause the death of the whole
leaf.
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32. Rice Sheath Blight (Rhizoctonia solani)
Management:
Seeding rate or plant spacing should be
optimized to avoid closer plant spacing or
dense crop growth which favors the
horizontal spread of the disease.
Need-based or real-time application of
nitrogen fertilizer is recommended in fields
known to have a high amount of inoculum.
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33.  Sheath blight is a fungal disease
caused by Rhizoctonia solani.
 Symptoms:
 Oval or ellipsoidal greenish gray
lesions, usually 1-3 cm long, on the
leaf sheath, initially just above the
soil or water level in the case of
conventionally flooded rice.
 under favorable conditions, these
initial lesions multiply and expand to
the upper part of the sheaths, the
leaves, and then spread to
neighboring tillers belonging to
different hills (transplanted rice) or
plants (direct-seeded rice).
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34.  lesions on the leaves
usually have irregular
lesions, often with gray-
white centers and brown
margins as they grow
older.
 in subtropical
environments, the
disease is mostly initiated
by sclerotia (up to two
million of which can be
produced per square
meter in a diseased
crop).
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35.  Management:
 Use a reasonable level of fertilizer adapted to
the cropping season.
 Use reasoned density of crop establishment
(direct seeding or transplanting).
 Carefully control of weeds, especially on the
levees.
 Drain rice fields relatively early in the cropping
season to reduce sheath blight epidemics.
 Use fungicide to treat seeds.
 Improve canopy architecture by reducing
seeding rate or providing wider plant spacing.
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36.  Leaf scald
 Leaf scald is a fungal disease
caused by Microdochium oryzae
 Symptoms:zonate lesions of
alternating light tan and dark
brown starting from leaf tips or
edges
 oblong lesions with light brown
halos in mature leaves
 translucent leaf tips and
margins
 Individual lesions are 1−5 cm
long and 0.5−1 cm wide or may
almost cover the entire leaf.
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37. Management:
 Use resistant varieties.
Contact your local agriculture office for an up-
to-date list of available varieties.
 Avoid high use of fertilizer. Apply Nitrogen in
split.
 Use benomyl, carbendazim, quitozene, and
thiophanate-methyl to treat seeds.
 In the field, spraying of benomyl, fentin
acetate, edifenphos, and validamycin
significantly reduce the incidence of leaf scald.
Foliar application of captafol, mancozeb, and
copper oxychloride also reduces the incidence
and severity of the fungal disease.
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38.  False smut
 Pathogen Name: Ustilaginoidea
virens
 False smut causes chalkiness of grains
which leads to reduction in grain
weight. It also reduces seed
germination.
 The disease can occur in areas with
high relative humidity (>90%) and
temperature ranging from 25−35 ºC.
 Rain, high humidity, and soils with high
nitrogen content also favors disease
development. Wind can spread the
fungal spores from plant to plant.
 False smut is visible only after panicle
exsertion. It can infect the plant during
flowering stage.
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39.  Symptoms: Individual rice grain
transformed into a mass of
velvety spores or yellow fruiting
bodies
 Growth of velvety spores
enclose floral parts
 Immature spores slightly
flattened, smooth, yellow, and
covered by a membrane
 Growth of spores result to
broken membrane
 Mature spores orange and turn
yellowish green or greenish
black
 Only few grains in a panicle are
usually infected and the rest are
normal
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40. Management:
 Keep the field clean.
 Remove infected seeds, panicles, and plant debris
after harvest.
 Reduce humidity levels through alternate wetting
and drying (AWD) rather than permanently flooding
the fields.
 Where possible, perform conservation tillage
and continuous rice cropping.
 Use moderate rates of Nitrogen.
 Use certified seeds.
 Resistant varieties have been reported. Contact
your local agriculture office for an up-to-date list of
available varieties.
 Treat seeds at 52°C for 10 min.
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41.  Rice Tungro Viral Diseases
(rice yellow orange leaf virus)
 Symptoms: Yellowing of the
plant and its stunted height can
be confused as nitrogen and
zinc deficiencies and water
stress,pest infestation such as
stem borer infestation, plant
hopper infestation, and rat
damage, andother diseases
such as grassy stunt virus
disease and orange leaf.
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43.  Grow tungro or leafhopper resistant varieties.
This is the most economical means of managing the disease.
There are tungro-resistant varieties available for the
Philippines, Malaysia, Indonesia, India, and Bangladesh.
Contact your local agriculture office for up-to-date lists of
varieties available.
 Practice synchronous planting with surrounding farms.
Delayed or late planting, relative to the average date in a
given area, makes the field susceptible for Tungro. Late-
planted fields also pose a risk to early planting in the next
season.
 Adjust planting times to when green leafhopper are not in
season or abundant, if known
 Plow infected stubbles immediately after harvest to reduce
inoculum sources and destroy the eggs and breeding sites of
green leaf hopper.
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44.  DISEASE: Ufra Disease of Rice
 PATHOGEN: Ditylenchus
angustus
Symptoms
1. Typical symptoms are a mosaic or chlorotic
discoloration of emerging or emerged leaves;
yellowish or pale green splash-patterns on affected
leaves and sheaths; and appearance of brown to dark
brown spots on leaves. Margins of affected leaves
become wavy. The collective symptoms are known as
ufra disease.
2. In case of early infestation, panicles may fail to emerge. The
symptoms of injury appear within one week in young plants
and in 10-15 days in plants at, or prior to, flowering.
• Affected seedlings show whitish discoloration
(chlorosis) at the early stage of infection
• Plants than are stunted and have deformed and twisted
leaves.
• panicles that are exserted, become twisted and
deformed, with unfilled grains.
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45.  Management
1. Use nematode free seeds
2. Crop rotation
3. The best way to control ufra is by completely drying
fields when they are fallow.
4. Ploughing to destroy foci (the origin or centre of a
disseminated disease) infection in stubbles
5. Chemical control by using diazinon appears
promising
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46. Bangladesh climatic condition is favorable
for disease .That's why farmers use huge
amount chemicals which is very harmful
for our ecosystem. Grow resistant variety,
proper cultural practice and proper use of
biological control agent like PGPM can be
became sustainable solution plant disease.
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