STUDIES ON LEAF SPOT DISEASES IN CHILLI (Capsicum annuum L.) CAUSED BY Alternaria alternata (Fr.) Keissler AND Cercospora capsici Heald and Wolf
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Date
2012-11
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K.R.C. COLLEGE OF HORTICULTURE, ARABHAVI (UNIVERSITY OF HORTICULTURAL SCIENCES, BAGALKOT)
Abstract
Among the diseases, Alternaria and Cercospora causes moderate damage to
foliage, fruit yield and quality of Chilli. Survey conducted during kharif /rabi of
2011-12 revealed that leaf spot diseases ranged from 1.33 to 61.33 and 2.67 to 58.67 per
cent respectively in Belgaum, Bagalkot, Dharwad and Haveri. Isolation, identification
and pathogenicity studies revealed that Alternaria alternata and Cercospora capsici
were the causal organisms.
Cultural studies confirmed that, the mycelial growth of A. alternata was
maximum in Richard’s agar and sporulation was maximum in Potato Dextrose Agar.
The mycelial growth of C. capsici was maximum in PDA. Physiological studies
revealed that, the mycelial growth of A. alternata was maximum at a temperature range
from 25 to 300C and sporulation was at 280C. The maximum mycelial growth of
C. capsici was observed at 250C.
Out of ten fungicides tested against both the pathogens in in-vitro,
propiconazole, difenconazole, benomyl, mancozeb + carbendazim at 500, 1000 and
2000 ppm concentrations showed the complete inhibition of mycelial growth. Among
ten botanicals, leaf extract of Eucalyptus citriodora at 15 per cent concentrations was
found effective against A. alternata. Whereas, against C. capsici, Calotropis procera at
15 per cent leaf extract was effective. Further, P. fluorescens was evaluated in in-vitro
against these pathogens, the growth of test fungus inhibited 44.64 and 67.85 per cent
respectively compared to control
For the management of Alternaria and Cercospora leaf spot diseases under
field conditions, lowest per cent disease index was noticed in combination spray of
(propiconazole 25% EC @ 0.05% + E. citriodora @ 10% + P. fluorescens @ 5 g/litre).
The number of fruits infected per plant and fruit yield parameter also showed similar
treatment effect.
Description
TH438
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