Disorders of vegetable crops - part 1

Importatnt physiological disorders of vegetable crops

    Crop

    Disorder

    Symptoms


    Chilling Injury

    Chilling sensitive at temperatures below 10°C.
    Consequences are failure to ripen and develop full colour and flavour, irregular/blotchy colour development, premature softening, surface pitting, browning of seeds and increased decay.

    Freezing Injury

    Freezing injury will be initiated at -1°C.
    Symptoms of freezing injury include a water soaked appearance and excessive softening of fruits with dull colour.


    Blossom end rot

    Lesions appear at blossom end of the green fruit.
    Water soaked spots appear at the point of attachment of the senescent petals.
    The affected portion of the fruit becomes sunken, leathery and dark coloured.


    Cat face

    Fruits are characterized by the distortion of the blossom end.
    Affected fruits have ridges, furrows, indentations and blotches.


    Cracking

    Three types – concentric, radial and cuticular.
    Common during rainy season when temperature is high, especially when rain follows long dry spell.

    Capsicum

    Blossom-end rot

    Deficiency of calcium in fruit

    Onion

    Freezing Injury

    Soft water-soaked scales rapidly decay due to subsequent microbial growth.

    Translucent Scales

    Resembles freezing injury.
    3-4 week delay in cold storage increases risk significantly.

    Garlic

    Sprouting of bulbs

    Excessive moisture or winter rains and supply of nitrogen.

    Splitting

    Delayed harvesting or irrigation after long spell of drought.




    Bhendi

    Chilling injury

    Discoloration, pitting, water-soaked lesions and increased decay.

    Freezing injury

    Occurs at temperatures lower than -1.8°C.

    Cucumber

    Freezing injury

    Freezing injury will be initiated at - 0.5°C (31°F).
    Symptoms include a watersoaked pulp becoming brown and gelatinous in appearance over time.

    Peas

    Freezing injury

    Freezing injury will be initiated at -0.6°C resulting in water soaking followed by rapid decay due to soft-rot bacteria.

    Potato

    Greening

    Surface of the tuber turns green on exposure to light.

    Black heart

    Sharply defined, purplish-grey to black area in center or cavities due to oxygen starvation.

    Chilling injury

    Gray to red-brown areas or black heart.

    Freezing injury

    Vascular tissue turns black and tubers leak when thawed.

    Blackspot

    Internal black spots due to bruising.

    Internal Brown Spot

    Brown Center / Hollow Heart and Translucent End
    Dry, corky reddish-brown or black spots appear on the tissue of the potato.

    Brinjal

    Chilling Injury

    Chilling sensitive at temperatures below 10°C.
    Symptoms are Alternaria rot, pitting, surface scald and blackening of seeds.

    Freezing Injury

    Freezing injuries are caused at - 1°C.
    Symptoms appear as water soaked pulp which finally turns brown.

    Cabbage

    Yellowing

    Gradual loss of green chlorophyll pigment and yellowing of the outer leaves.
    Sensitive to ethylene, which causes both leaf yellowing and leaf shedding.

    Black Leaf Speck

    Development of individual specks, randomly distributed over the leaf.
    Initially the specks are small in size, but they may develop further in storage and unite into spots as large as 2 mm (0.08 in) in diameter.

    Physical Injury

    Damage to the midribs often occurs during field packing and causes increased browning and susceptibility to decay.

    Chilling injury

    Occurs during storage at 0°C for 3 months or longer.
    Symptom is midrib discoloration, especially on outer leaves

       

Last modified: Friday, 16 December 2011, 7:41 AM