Post harvest diseases of brinjal

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Post harvest diseases of brinjal
Anthracnose Colletotrichum melongenae
Fruit rot Phomopsis vexans
Fruit rot Alternaria solani
Fruit rot Pythium aphanidermatum
Fruit rot Phytophthora nicotianae var nicotianae
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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

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• 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

Conidia from pycnidium
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• Epidemiology
• Temp - 29oC (fungal growth)
• Storage rot of fruits is maximum at 25oC
• Management
• Seed treatment - hot water _at_ 50oC for 30 min
• Nursery - 0.2 difolatan or captan 0.2 _at_ weekly
  interval
• Field - Zineb 0.2
• Bordeaux mixture 0.8

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Fruit rot - Alternaria solani

• Small, concentric dark brown sunken spots
• Spots coalesces covers entire fruit
• Fungus
• Hyphae - septate, branched, light brown becoming
  darker with age
• Conidia - single, muriform, beaked and dark in
  color
• Source of infection - infected seeds and plant
  debris
• Pusa purple - moderately resistant

Alternaria solani conidia. Note the transverse
and vertical septa and the long "beak
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• Favourable conditions
• Temp - 25 to 30oC
• Sporulation abundant when rains are frequent
  and heavy
• Mode of survival and spread
• Conidia and mycelium in the soil and debris -
  remain viable for gt 17 months
• Conidia are windborne
• Control
• Spraying of zineb 0.2 or mancozeb 0.2

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Fruit rot - Pythium aphanidermatum

• Referred as cottony leak
• Decay begins at blossom end
• Purple colour of the skin bleaches and turns to
  tan and wrinkling follows
• Fleshy tissue becomes watery
• White cottony mycelium of the fungus covers the
  surface
• Fungus
• Mycelium - coenocytic, white and measures 2.8 -
  7.5 µm in dia
• Produce sporangia, zoospores, and oospores
• Oogonia - spherical, smooth walled, terminal on
  lateral hyphae

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• Mode of spread and survival
• Survival Through oospores present in the soil
• Spread Through irrigation water, implement
  during cultural operations
• Favourable conditions
• Excessive soil moisture
• High humidity
• Over crowding of seedling
• Control
• Remove affected plants and burn
• Avoid water logging condition
• Drench the soil with 1 Bordeaux mixture
• Fruits should not be allowed to touch the soil
• Do not store the infected fruits with healthy
  fruits

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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

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• 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

A Sporangia. B Zoospore. CChlamydospore. D
Oospore.
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Anthracnose - Colletotrichum melongenae

• Sunken lesions on fruits vary in size
• Upto 1.3cm wide and may coalesce
• Tan colored ooze of fungal spores appear on
  lesions
• Fruit dries become black fruit drop
• Fungus
• Mycelium - septate, branched light pink to
  brown
• Acervuli - simple globose and dark brown
• Conidiophore - erect and hyaline
• Conidia - hyaline, one celled, oval or oblong

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• Mode of spread and survival
• Survives on crop debris as acervuli
• Spores dispersed by rain splash
• Epidemiology
• RH - 100
• Temp - 21 to29oC
• Control
• Field sanitation - destruction of infected plant
  debris
• Other host plant - S. torvum
• Harvesting of fruits before they over ripe
• Zineb or ferbam spray at 10 days interval