Studies on Maydis Leaf Blight of Maize Caused By Drechslera maydis (Nisikado) Subram. And Jain
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Date
2012
Authors
Hulagappa
Journal Title
Journal ISSN
Volume Title
Publisher
UAS, Dharwad
Abstract
The investigation on maydis leaf blight (MLB) of maize caused by Drechslera
maydis (Nisikado) Subram and Jain, comprised of disease survey, pathogen variability
studies, evaluation of fungicides, bioagents, phytoextracts and field management of
the disease were conducted during kharif and rabi 2011 at Main Agricultural
Research Station, University of Agricultural Sciences, Dharwad. The results of the
investigation are summarized hereunder.
During kharif 2011, maximum disease severity was recorded in Ranebennur
(56.26%). Least severity was noticed in Kushtagi (33.88%). During rabi 2011,
maximum disease severity was observed in Ranebennur (50.26%). Least severity was
noticed in Kushtagi (27.88%).
During the survey programme, the maydis leaf blight infected leaf samples
were collected and pure hyphal tip cultures of twelve isolates were maintained on
potato dextrose agar. Studies on morphological and cultural variability indicated that,
isolate Dm1 was found to be fast growing, excellent sporulation with deep black
pigmentation. Random Amplified Polymorphic DNA studies distinguished the twelve
isolates into major cluster, A and B. Majority of the isolates were in cluster A under
various sub-clusters, showing some degree of variability. Cluster B has 6 isolates in
case of sub cluster A1, it has got a single isolate Dm5, which was showing
diversification from other isolates.
Propiconazole 25% EC @ 0.1% found to be effective under in vitro studies
which recorded maximum mycelial inhibition at all the concentrations tested followed
by Hexaconazole 4% WP + Zineb 68% WP. Among the botanical, neem leaf extract
and bioagent, Trichoderma virens recorded maximum mycelia inhibition. Field
studies indicated that two sprays of Propiconazole 25% EC @ 0.1% at 35 and 50 days
after sowing found to be highly effective (20.68% PDI, 73.46 q/ha grain yield and
10.96 t/ha fodder yield) in the management of the disease.