Studies on Sorghum Ergot Caused by Claviceps africana Frederickson Mantle and de Milliano
Loading...
Date
2011
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
UAS, Dharwad
Abstract
Ergot (sugary disease) caused by Claviceps africana has become major
constraint particularly in the cultivation of sorghum hybrids and hybrid seed
production. The survey data indicated that average disease incidence of 6.6% and
severity of 17.56 PDI was recorded in Northern Karnataka. The maximum incidence
of 12.02% and severity of 25.94 PDI were observed in Belgaum district followed by
Dharwad, Gadag, Haveri and Raichur. Isolation and morphological studies confirmed
that C. africana as causal organism of the disease. The pathogen attained maximum
growth on 12th day of incubation in T2 broth. T2 agar and Kirchhoff’s agar media were
the best for colony growth and sporulation.
The maximum dry mycelial weight of C. africana was observed at 200C (114
mg) and it was least at 400C (12 mg). In vitro cent percent inhibition of mycelial
growth was observed with Hexaconazole 5% EC, Captan 70% + Hexaconazole 5%
and Hexaconazole 4% + Zineb 68%. Adusoge at 10 per cent was found most effective
among plant leaf extracts. In vitro cent percent inhibition of mycelial growth was
observed with Achook 0.15% EC, Neem Extra Power 10000 ppm and Nimbicidine
0.03% EC @ 15% concentration.
The sorghum grain yield loss of 38.47% due to ergot disease was observed
with unsprayed treatment over five sprays of Hexaconazole @ 1ml/l. Yield loss due to
ergot disease decreased with increased number of Hexaconazole sprays.
Hexaconazole 5% EC @ 1 ml/l, Propiconazole 25% EC @ 1 ml/l and Captan
70% + Hexaconazole 5% @ 2 g/l were found effective in reducing the incidence and
severity of the disease and thereby increasing the sorghum grain yield. Hexaconazole
@1 ml/l was found most effective. None of the plant leaf extracts was effective to as
that of Hexaconazole. None of the genotype showed resistant reaction against the
disease among the ten genotypes screened under artificial condition.