SHEATH ROT

DISEASE OF FIELD CROPS

2. Casual organism : Sarocladiumoryzae
Symptoms :
Initial symptoms are noticed only on the upper
most leaf sheath enclosing young panicles

3. The flag sheath show oblong or irregular greyishbrown
spots. They enlarge and develop grey cenreand brown
margins covering major portion of the leaf sheath.
The young panicles
may remain within
the sheath.
The affected sheath and
Panicles rot and whitish
powdery fungal growth
is formed inside leaf sheath

4. The disease spreads mainly through air-
borne conidia and also seed-borne.
Primary source of inoculumis by means of
infected plant debris. Secondary spread is
by means of air borne conidia produced on
the leaf sheath.

5. Apply recommended dose of ferilizers
Adopt optimum spacing
Spray carbendazim@ 500g or edifenphosor
mancozeb@ 2kg/ha at boot leaf stage and 15
days later
Soil application of gypsum @ 500kg/ha in two
splits
Application of neemseed kernel extract 5% or
neemoil 3% . First spray at boot leaf stage and
second 15 days later.

6. Casual organism : Sclerotiumoryzae
Symptoms:
Small black lesions are formed on the outer leaf
sheath near the water line they enlarge and
reach the inner leaf sheath also.
The affected tissues rot and abundant sclerotia
are seen in the rotting tissue. If the diseased
tiller is opened large number of sclerotiacan
be seen.

8. In the field, sclerotiaare mostly distributed
in the upper 5 to 10cm of the soil. These
sclerotiafloat on the water surface and
germinate when attached to rice stem, with
the fungus subsequently growing into the
plant tissue. The sclerotiaare produced
soon after infection on the inside and
outside of stems. Irrigation water carries
the sclerotiato other fields.

9. use recommended dose of fertilizer
Deep ploughingin summer and burning of
stubbles
Use of resistant varitieslike Basumati3 ,
Basumati370
Drain the field to reduce sclerotia
Spray of chemicals such as fentinhydroxide
at mid tilleringstage .