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20121
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Subject: Plant Pathology × Author: Hulagappa × End date: 2017 × Start date: 2010 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Studies on Maydis Leaf Blight of Maize Caused By Drechslera maydis (Nisikado) Subram. And Jain
    (UAS, Dharwad, 2012) Hulagappa; S.I. Harlapur
    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.