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Aim: The present study was undertaken to study the morphological and molecular diversity of Ganoderma spp. causing foot rot of arecanut in dry tracts of Southern Karnataka. Methodology: A total of 20 samples isolated from diseased areca palms in three districts of Karnataka were identified based on morphological and molecular characteristics. Qualitative data of cultural characteristics were transformed into code and a binary matrix was generated. Total genomic DNA was isolated and ITS region was amplified using universal primers ITS1 and ITS4. PCR amplicon was directly sequenced and phylogenetic analysis was carried out. Results: The dendrogram generated from the cultural morphological characteristics showed clear variations among Ganoderma isolates causing foot rot. DNA amplification of Ganoderma isolates with fungal universal primers (ITS1 and ITS4) was observed at 650 bp in all isolates tested. Taxonomic correlation of isolates upon NCBI web proved that the isolates were genetically related to Ganoderma spp. with 89-99.49 per cent identity and confirmed the taxonomic identity of isolates used in this study. Interpretation: Phylogenetic analysis of arecanut isolates of southern Karnataka are distinct as evidenced by forming separate cluster. Based on gene homology, G. ryvardenni and G. casuarinicola are new species reported as causal agent of foot rot in arecanut from Karnataka. The ITS gene sequences of four isolates viz., AG3 (MN 784436), AG4 (MN 784437), AG11 (MN 784438), and AG20 (MN 78449) were deposited in NCBI gene bank. Key words: Arecanut, Foot rot, Ganoderma, Phylogeny, Species diversity

In vitro efficacy of seventeen new molecules of fungicides were evaluated against Bipolaris setariae causing leaf blight on browntop millet at University of Agricultural Sciences, GKVK, Bangalore in order to find out effective fungicide against B. setariae. Mancozeb, among the six contact fungicides recorded cent per cent inhibition over control at 500 and 1000 ppm with mean inhibition of 96.54 per cent. Among the six systemic fungicides tested at 50, 100 and 150 ppm, propiconazole exerted 100 per cent inhibition of mycelial growth followed by tebuconazole which accounted 100 per cent inhibition at 100 and 150 ppm with mean inhibition of 94.69 per cent and cymoxanil + mancozeb among the five combi-product fungicides tested (100, 250 and 500 ppm) exhibited maximum (79.01 %) mean inhibition of mycelial growth. Among all groups, tricyclazole was found to be least effective.

Browntop millet was newly included in the millet cropping system in India as one of the small millet. Incidence of leaf blight was observed to be severe in all millet growing regions of India and the causal organism was confirmed as B. setariae using molecular tools viz., ITS and GPDH genes. As the crop was newly included in the millet system, investigation was needed to carry out about disease causing agents their biology and culture conditions. In this study, an attempt was made to identify the ideal culturing and physiological requirements for culturing B. setariae. Results revealed that solid media such as Czapek Dox agar (CDA) and host leaf decoction agar with 2 per cent sucrose are ideal for better growth and abundant sporulation while, pH 6.0 to pH 7.0 were found to be ideal for radial mycelial growth and sporulation. These cultural and physiological conditions can be used for the future studies while working on the pathogen causing browntop millet leaf blight.

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