Division – Mycota Class – deuteromycetes
Order –moniliales
Family – Dematiaceae
Genus – Alternaria
Occorancer : species of alternaria are Saparophytic as well as week parasites Fungus . They are cosmopolitant in distribution in nature. They are found abundantly in house dust and cause of chiffuncai HAY FEVER . alternia solani cause dark leaf spote in brassica species . a triticina cause leaf blight of wheet .
Mycelium is septale . branched and spread to intercellular spaces of the host tissue without historia . it is light brown colour becomes black coloured.
Alternaria , reproduce only by Asexual method by meansof conidia , which are born at the tip of conidiophore. They are short and dark colour . emerge through the stomata or from the death or damage parts of host leaves. Conidia are borne on the coniodiophore from a bud which is formed on that cell. Conidia are born singly but sometiimes they are formed in chain of two or three . the conidia are large dark colore mostly obclavate , terminating in long , septal , beak
Like structure. The body of conidium is divides into small compartments the conidia vary in size but they are large bottle shapr multicellular with both trsnsverse and longitudnal septaoccring typically. The conidia when mature get deached and are displaced by wind. Under favourable condition conidia germinated readly and five rotten germ tube arise from single conidium
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