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Biological management of alternaria blight of onion

KrishiKosh

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Title Biological management of alternaria blight of onion
 
Creator T.Pramod Kumar
 
Contributor M.G.Palakshappa
 
Subject Plant Pathology
 
Description Among the several diseases, Alternaria leaf blight is one of the most destructive foliar
disease which causes heavy loss in onions. Survey during Kharif 2006 revealed that purple
blotch was severe in all six districts of survey. Isolation and morphological studies revealed
Alternaria porri (Ellis) Cif. and A. alternata (Fr) Keissler, Beth. as pathogens.
From onion rhizosphere, T. harzianum, Pseudomonas sp. and Bacillus sp were
isolated. All nine amendments tested for compatibility supported cent per cent growth of T.
harzianum. Distillery yeast sludge and pressmud stimulated growth of P. fluorescens. Caster
cake recorded highest inhibition of A. porri and A. alternata.
Of ten plant extracts, tridax, calotropis, NSKE, clerodendron, bougainvillea, ocimum
and pongemia supported cent per cent growth of T. harzianum. Calotropis, NSKE and neem
leaf extracts stimulated growth of P. fluorescens and B. subtilis. Nimbicidin and neem leaf
extract were inhibitory to A. porri and A. alternata.
Trichoderma viride was most effective against A. porri, followed by T. harzianum
(native isolate). In case of A. alternata, T. harzianum (native isolate) was best.
Of 15 substrates, molasses yeast medium followed by broken sorghum grains,
sorghum grains, broken maize grains, wheat bran and maize grains supported highest
population of T. harzianum. Saw dust recorded least population. In poly propylene bags,
same was noticed with slight increase in population than in conical flasks.
Among 12 organic solid and liquid media, maximum growth of T. harzianum was
noticed in sterilized local and jersey cowdung, followed by unsterilized and sterilized
buttermilk.
In field of bio-agents, mancozeb followed by application of enriched FYM + seed
treatment with T. harzianum + 3 sprays of T. harzianum (T3) proved best with least disease
index score and highest yields. Seedling vigour index, average weight, diameter and
circumference of the bulb were superior in T3 as compared to T8.
 
Date 2016-10-24T19:16:06Z
2016-10-24T19:16:06Z
2007
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/81667
 
Format application/pdf
 
Publisher UAS, Dharwad