Stem rot disease - GAURAV KUMAR PAL

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Flag smut of wheat
 Pathogen:- Urocystis agropyri
 Symptoms:• Attacks the leaves and stems of
wheat plants.
• The fungus produces grey-black
lines of spores that run parallel to
the leaf veins.
• Infected plants are often stunted and
the flag leaf twisted.
• Spores on infected leaves and straw
are spread onto the grain and soil
surface.
• Flag smut has both a soil and seed
borne disease.
Flag smut
Control of flag smut disease
 By resistant varieties
• NP 165,WG 189,VL 426,HD 2117, HW161,HB 121, HB 113, etc.
 By seed treatment
• Seed treated with sulpher or organo-mercurials.
• Foliarflo-C, Maxiflo, Vitaflo C, Vitavax 200FF, Proguard Plus, Proleaf
Plus, Rancona C , etc.
• Clean seeds should be used.
 By crop rotation
• Also effective in controlling this disease.
Foot rot disease :-(Bakanae disease)
 Pathogen:- Fusarium
moniliforme
 Symptoms :• abnormal elongation of plants.
• drying of leaves at late infection.
• Infected plants several inches taller than
normal plants .
• Thin plants with yellowish green leaves
and pale green flag leaves.
• infected seedlings with lesions on roots
die which may die before or after
transplanting .
Foot rot disease
Control:By resistant varieties
• Co-18,Co-22,ADT-8,PTB-7,G.E.B. 24, etc
By seed treatment
• Clean seeds should be used.
• Salt water can be used to separate lightweight,
infected seeds from seed lots.
• Seed treatment using fungicides such as thiram,
thiophanate -methyl, or benomyl is effective
before planting.
Stem rot disease :-
Pathogen :- Sclerotium
Symptoms:-
oryzae
• Small, irregular black lesions on the outer
leaf sheath near water level.
• Lesions expand as the disease advances
• Infected stem rots.
• Visible numerous tiny white and black
sclerotia and mycelium inside the infected
culms
• Infected culm lodges and caused unfilled
panicles and chalky grain
• Severe infection causes tiller death
• The disease aggravates the plants to lodge
Stem rot disease
Stem rot disease control
 By resistant varieties
•
Basumati 3, Basumati 370,Mashkan 7,Mashkan 41,Bara 62 etc
 By crop rotation
• Proved beneficial for disease control.
 By proper manuring
• A balanced use of fertilizer with high potash and lime to increase soil
pH reduces stem rot infection and increases yield.
 By spraying
•
•
•
Chemicals such as fentin hydroxide sprayed at the mid-tillering stage.
Thiophanate-methyl sprayed at the time of disease initiation can reduce stem
rot incidence in the rice field.
The use of fungicides such as Ferimzone and validamycin A also show
effectively against the fungus.
Sheath blight:-
 Pathogen:- Rhizoctonia solani Kuhn
 Symptoms:•
•
•
•
•
•
Initial lesions are small, ovoid, greenish-gray and
water-soaked.
develop near the water line in lowland fields.
Older lesions are ovoid with a grayish white center
and light brown to dark brown margin.
Lesions may reach the uppermost leaf under
favorable conditions.
Lesions may forming bigger lesions with irregular
outline and may cause the death of the whole leaf.
Severely infected plants produced poorly filled or
empty grains, especially those on the lower portion of
the panicles
Control of Sheath blight: plant spacing
•
•
plant spacing should be optimized.
Dense crop growth which favors the horizontal spread of the disease.
 Sanitation
•
•
Removing of weeds, can help control sheath blight.
Pathogen attacks weeds which are commonly found in rice fields.
 Spraying
•
Spraying infected plants with fungicides, such as benomyl and iprodione,
and antibiotics, such as validamycin and polyoxin, is effective against the
disease.
 Biological control
• Trichoderma & gliocladiumare used to control disease
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