Browsing by Author "Nirmal Kumar, B.J."

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    New ooccurrence of the Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) infestation on cocoa in India.
    (2023) Madhu, T.N.; Thava Prakasa Pandian, R; Elain Apshara, S.; Bhavishya; Josephrajkumar, A.; Nirmal Kumar, B.J.; P. Santhosh Kumar
    Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) is a highly polyphagous insect pest, which inflicts serious economic damage on many agricultural and horticultural crops globally. During our recent surveillance surveys, an unusual defoliation was noticed by a caterpillar pest on cocoa saplings at ICAR - Central Plantation Crops Research Institute, Regional Station, Vittal farm, Karnataka, India. Morphological identification and molecular characterization using mitochondrial cytochrome-c-oxidase (COI) gene confirmed the collected insect samples as S. litura. Hitherto, this species was only known to infest Leucaena leucocephala (CABI), a shade tree of cocoa plantations in Indonesia. To the best of our knowledge, this is the first record of infestation by tobacco cut worm on cocoa in India. Consequently, solarization of rooting medium has been suggested for the destruction of the quiescent pupal stage.
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    Severe outbreaks of late blight on potato and tomato in South India caused by recent changes in the Phytophthora infestans population
    (2015) Chowdappa, P.; Nirmal Kumar, B.J.; Madhura, S.; Mohan Kumar, S.P.; Myers, K.L.; Fry, W.E.; Cooke, D.E.L.
    Late blight, caused by Phytophthora infestans, has emerged as the most destructive disease of potato and tomato in South India since 2008. One hundred and fifty-seven isolates of Phytophthora infestans, 63 from potato and 94 from tomato, were collected from major potato and tomato production areas of South India between 2010 and 2012. Their phenotypic and genotypic characteristics were determined and compared with reference isolates. Isolates were characterized based on mating type, in vitro metalaxyl sensitivity, mitochondrial DNA haplotype, RG57 DNA fingerprinting patterns, SSR markers and aggressiveness on potato and tomato, in order to monitor population changes in P. infestans. All isolates were A2 mating type, metalaxyl resistant, mtDNA haplotype Ia and had RG57 and SSR fingerprints almost identical to the 13_A2 clonal lineage reported in Europe. Variation at the D13 and SSR4 loci allowed discrimination of minor variants, designated as 13_A2_3, 13_A2_3b, 13_A2_3c and 13_A2_1. A comparison of the lesion diameters caused by 157 isolates on detached leaflets of three potato and tomato cultivars showed all isolates to be equally aggressive, confirming that the same clonal population is infecting both hosts. This study demonstrates that the 13_A2 lineage was responsible for severe late blight outbreaks on potato and tomato in South India and has replaced the prior population represented by the US-1 and other genotypes. Revised management strategies will be required to combat this destructive 13_A2 clonal lineage and monitoring of the population across other potato- and tomato-growing regions of India is warranted.
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    Xylosandrus crassiusculus (Motschulsky) on Cocoa Pods (Theobroma cacao L.): Matter of Bugs and Fungi
    (2022) Shivaji Hausrao Thube; R. Thava Prakasa Pandian; Josephrajkumar, A.; Bhavishya; Nirmal Kumar, B.J.; Dnyaneshwar M. Firake; Vivek Shah; T. N. Madhu; Enrico Ruzzier