Post
harvest diseases of brinjal
Anthracnose
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Colletotrichum melongenae
fruit rot:
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Phomopsis vexans
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Alternaria solani
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Pythium aphanidermatum
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Phytophthora nicotianae var nicotianae
Fruit
rot - Phomopsis vexans
—First phase - blight
on young seedlings
—Stem - girdled
slightly above the soil line, plant topples and dies
—Stem lesion - dark
brown, becoming grey in the centre as pycnidia
develops
—Leaf - irregular
brown spots
—Fruits – soft, watery
& decays
—Finally black,
mummified as pycnidia develop abundantly
over the surface
Fungus
—Pycnidia - with or without
beak, brown to black
—
—Conidiophores -
hyaline, simple or branched,
—
—Conidia - hyaline,
one celled and subcylindrical
—
— Stylophores - filiform, curved, hyaline, septate
Mode of spread and survival
—Seed borne
—
—Spread by rain
splashes, implements and insects
—
—Survives in infected
plant debris in soil
Epidemiology
—Temp - 29oC
(fungal growth)
—
—Storage rot of fruits
is maximum at 25oC
Management
—Seed treatment - hot
water @ 50oC
for 30 min
—
—Nursery - 0.2 % difolatan or captan 0.2% @ weekly
interval
—
—Field - Zineb 0.2 %
Bordeaux mixture 0.8%
Fruit
rot - Phytophthora nicotianae var nicotianae
—Fruits - Small, water
soaked lesions
—Skin - discoloration,
turns greyish brown, and develop
white cottony mycelium in humid weather
—Rotten parts become
depressed and develops wrinkles
—Rotting spread deep
into the pulp and turns brown, watery & soft
—Rapidly spreads
during rainy season
Fungus
—Hyphae - 5 to 6 μm in dia
—Spherical hyphal swellings are common
—Zoosporangia - sub
hyaline, oviod, pyriform borne on short stalk
Control
—Removal and
destruction of the affected fruits
—
—Spraying the crop
with Difolatan (0.3%) thrice at an
interval of 10 days effectively controls the disease
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