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Post harvest diseases of brinjal

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Title: Post harvest diseases of brinjal


1
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
2
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

3
  • 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
4
  • 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

5
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
6
  • 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

7
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


8
  • 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

9
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

10
  • 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.
11
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

12
  • 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
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