economically important diseases of leeks in sri lanka

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Economically Important Diseases of Leeks in

Sri Lanka

By;D.N.NanayakkaraUva Wellassa University of SriLanka

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INTRODUCTIONScientific name : Allium porumFamily : AlliaceaeEdible part of the leek plant is a bundle of

leaf sheaths

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Diseases of Leeks• Fusarium Foot Rot• Purple Blotch• Leaf Blight• Bacterial Blight• Botrytis leaf spot• Pink root• Onion maggot• Oedema

Economically Important Diseases

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Fusarium Foot Rot

Main fungal pathogenCaused by;

Fusarium avenaceum Fusarium oxysporum

Found on seedlings and mature plantsUp to 27% of plants were missing at

harvestCosmetic damage

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Symptoms : Plants mainly develop pale yellow brown

colour or pink crown or basal rot Reduced growth

• Control methodsUse recommended fungicides;⁻ Octave - Prochloraz⁻ Bavistan - Carbendazim ⁻ Thiabendazole

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Purple BlotchCaused by Alternaria porriFound on mature plantsDamage can be cosmetic or severe in

mature plantingsCausing plant deathDecrease marketability

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Symptoms: Purple oval lesions darken with spore

formation Severe infections blotching extends down

the stem• Control

Apply ; Difenconazole Iprodione.

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Leaf BlightCaused by Stemphylium botryosumFound on mature plantsCosmetic damageCause both primary and secondary

infectionsSymptom :

pale oval lesions which turn brown after spore production

Control : Apply “Difenconzole & Iprodine“

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Bacterial BlightCaused by Pseudomonas syringaeFound on seedlings and mature

plantsSeed borne pathogenInfected plant produce infected

seeds

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Symptoms: Brown leaf lesions surrounded by yellow

hole Longitudinal water soaked tissues

extending as a narrow strip Leaf distortion Chlorosis Shank staining Leaves are light green in colour and curled

Control Hot water treatments Use certified seeds

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Other DiseasesSmudgeBotrytis leaf spotPink root OedemaOnion maggot

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THANK YOU!