Browsing by Author "Sosamma, V.K."

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    Additional host records of root-knot nematode, Meloidogyne incognita
    (2007) Sundararaju, P.; Sosamma, V.K.; Koshy, P.K.
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    Additional host records of root-knot nematode, Meloidogyne incognita
    (2007-02-08) Sundararaju, P.; Sosamma, V.K.; Koshy, P.K.
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    Additional hosts of the burrowing nematode, Radopholus similis, infesting coconut palm in South India
    (2007-02-08) Sosamma, V.K.; Koshy, P.K.
    The hoel atatua of twenty-four specie from sixteen plant families -was teated gainst RadophoJua acnilla. Adenanthera pavqai. Taaoar indue tedica, Vicia faba. Careya arborea, Lagenaru vulgarta, Cucurbita ptoo. Trichoeaathca anguxoa, Fieus reltgtoaa, and Phoeni* dactyUfera were recorded aa hoeta for R. jrunhis. Except for Cucurbita pepo. all are new boat record* for R, aim ilia.
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    Biological control of Meloidogyne incognita on black pepper by Pasteuria penetrans and Paecilomyces lilacinus
    (1997-06) Sosamma, V.K.; Koshy, P.K.
    Root-knot nematode, Meloidogyne incognita causes considerable damage to black pepper (Piper nigrum L.). Efficacy of two known bio-control agents namely Pasteuria penetrans, an endospore forming bacteria and Paecilomyces lilacinus, a parasitic fungus on eggs for the control of M. incognita on black pepper was studied in pots under greenhouse condition. P. Penetrans and P. lilacinus reduced nematode population, root-gall indices and improved the growth of the plants and root mass production significantly. Fifteen per cent reduction was noticed in the vine length of plants inoculated with nematode alone while it was only 8 to 15% in vines treated with either P. lilacinus or P. penetrans or both with nematodes. Number of leaves/nodes produced was maximum in control plants compared to a minimum in nematode inoculated vines. Fresh shoot and root weight were significantly greater in all treatments infested with M. incognita in the presence of one or both the bio-control organisms than M. incognita alone. Among the two biocontrol agents studied, /. lilacinus was more effective compared to /. penetrans, but combination of both the organisms (PI + PP) was found to be very effective in the management of root-knot nematode in black pepper. Both /*. lilacinus and P. penetrans did not cause any adverse effect on plant growth and they were found to survive and effective even after two years of innoculation under greenhouse conditions. The natural occurrence of P. penetrans on M. incognita on cardamom from Vandanmedu, Idukki district, Kerala is reported for the first time. Black pepper being a perennial crop is a very good host for the maintenance of P. penetrans on M. incognita.
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    Biological control of Meloidogyne incognita on black pepper by Pasteuria penetrans and Paecilomyces lilacinus
    (2007-02-08) Sosamma, V.K.; Koshy, P.K.
    Root-knot nematode, Meloidogyne incognita causes considerable damage to black pepper (Piper nigrum L.). Efficacy of two known bio-control agents namely Pasteuria penetrans, an endospore forming bacteria and Paecilomyces lilacinus, a parasitic fungus on eggs for the control of M. incognita on black pepper was studied in pots under greenhouse condition. P. Penetrans and P. lilacinus reduced nematode population, root-gall indices and improved the growth of the plants and root mass production significantly. Fifteen per cent reduction was noticed in the vine length of plants inoculated with nematode alone while it was only 8 to 15% in vines treated with either P. lilacinus or P. penetrans or both with nematodes. Number of leaves/nodes produced was maximum in control plants compared to a minimum in nematode inoculated vines. Fresh shoot and root weight were significantly greater in all treatments infested with M. incognita in the presence of one or both the bio-control organisms than M. incognita alone. Among the two biocontrol agents studied, /. lilacinus was more effective compared to /. penetrans, but combination of both the organisms (PI + PP) was found to be very effective in the management of root-knot nematode in black pepper. Both /*. lilacinus and P. penetrans did not cause any adverse effect on plant growth and they were found to survive and effective even after two years of innoculation under greenhouse conditions. The natural occurrence of P. penetrans on M. incognita on cardamom from Vandanmedu, Idukki district, Kerala is reported for the first time. Black pepper being a perennial crop is a very good host for the maintenance of P. penetrans on M. incognita.
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    Biological Control of Pests of Coconut
    (2000) Pillai, G.B.; Antony, J.; Mohan, K.S.; Mariamma Daniel; Devasahayam, S.; Sathiamma, B.; Dangar, T.K.; Ramachandran, C.P.; Abraham, V.A.; Bhat, S.K.; Sreekumar, K.R.; Sukumaran, A.S.; Chandrika Mohan; Murali Gopal; Sosamma, V.K.; Gulsar Banu, J.
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    Burrowing nematode a potential threat to agriculture
    (2007-02-08) Koshy, P.K.; Sundararaju, P.; Sosamma, V.K.
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    Culturing of burrowing nematode, Radopholus similis on carrot discs
    (2007-02-08) Koshy, P.K.; Sosamma, V.K.
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    Culturing of Radopholus similis within mesocarp of coconut
    (2007-02-08) Koshy, P.K.; Sosamma, V.K.
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    Distribution of entomopathogenic nematodes in coconut gardens of Kerala State and pathogenicity of Steinernema feltwe to red weevil, Rhynchophorus ferrugineus
    (2006) Sosamma, V.K.
    Steinernema feltiae and Steinernema spp. were found at five and Heterorhabdtiis indica at 128 sites out of 480 samples collected from coconut gardens in 10 districts of Kerala. Two hundred and fourteen (45%) were positive for Rhabditis sp. and 16(3%) for Aphelenchus sp. Analysis of soil samples revealed the highest occurrence of EPN in sandy loam soil followed by laterite and alluvial soil types. Soil samples collected from termite mounts did not yield any EPN. Forty per cent of soil samples yielded an earthworm Fridericia khallikottosus alongwith entomophilic nematodes. This indicates that EPN is not harmful to other non-targeUbeneficiai organisms. Ninety per cent of the frass collected from red weevil infested coconut palms yielded Teratorhabditis palmarum, which was only entomophilic and not pathogenic to red weevil. In bioefficiency tests of S. feltiae, on red weevil grubs, mortality occurred in 3-4 days. When the last instar larvae of Red weevil inoculated with 1000 nematodes, the adults emerged, were of reduced size compared to healthy ones. Soil application of S. feltiae against red weevil adults in the net house in the field resulted in 55-60% mortality of weevils, while in control it was only 10-12%.
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    Effect of different types of soils on multiplication of Radopholus similis and growth of coconut seedlings
    (2007-02-08) Sosamma, V.K.; Koshy, P.K.
    The influence of different soil types viz. laterite, riverine alluvium, coastal alluvium (Coastal sand), loamy sand and reclaimed marshy or Kari soil on multiplication of Radopholus similis and growth of coconut seedlings was studied. Best growth of uninoculated seedlings was recoded in riverine alluvium followed by the laterite spil. Plant growth was poor in reclaimed marshy soil with maximum per cent clay, silt and a minimum of coarse sand with a pH of 4.1. In inoculated plants the maximum plant damage was recorded in riverine alluvium followed by loamy sand and coastal sand and the least in laterite soil. Maximum nematode multiplication was obtaind from loamy sand followed by riverine alluvium and the least in Kari soil.
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    Effect of leaf extracts on the mortality of Meloidogyne incognita
    (2007-02-08) Sosamma, V.K.; Jayasree, D.; Koshy, P.K.
    Studies were conducted to evaluate the nematicidal property of water extracts obtained from some commonly available weed/plant leaves against 2nd stage juveniles of Meloidogyne incognita. Of the sixteen plants tested 100 per cent mortality was observed with Moringa pterigosperma and Momordica charantia at 1:5 dilution after 24 hours whereas with Leucas aspera 100 per cent mortality was observed only after 48 hours in the same dilution. Hundred per cent mortaility of juveniles was observed with M. pterigosperma after 72 hours at 1:10 dilution also. Leaf extracts of certain plants are know to have nematicidal or nematostatic properties against several plant parasitic nematodes (Khanna, 1991; Hussaini, et al, 1996; Nandal and Bhatti, 1983; Krishnamurthy et ah, 1989; Saxena et ah, 1990). The present work is an attempt to study the nematicidal potential of extracts of some locally available weeds/plants against 2nd stage juveniles of the root-knot nematode, Meloidogyne incognita (Kofoid and White) Chitwood.
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    Effect of Meloidogyne incognita population on black pepper
    (2007-02-08) Koshy, P.K.; Premachandran, D.; Sosamma, V.K.; Prem Kumar, T.
    Meloidogyne incognita was found to be pathogenic to black pepper causing stunting and yellowing of the plants and reduction in root and shoot weights. Reduced growth of plants and intensity of galling was correlated with the increase in initial nematode population. An initial nematode inoculum level of 10 larvae per plant caused severe damage over a period of one year.
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    Effect of Meloidogyne incognita population on black pepper
    (1979) Koshy, P.K.; Premachandran, D.; Sosamma, V.K.; Prem Kumar, T.
    Meloidogyne incognita was found to be pathogenic to black pepper causing stunting and yellowing of the plants and reduction in root and shoot weights. Reduced growth of plants and intensity of galling was correlated with the increase in initial nematode population. An initial nematode inoculum level of 10 larvae per plant caused severe damage over a period of one year.
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    Effect of Paecilomyces lilacinus, Pasteuria penetrans and VAM on the growth of coconut seedlings infested with Radopholus similis
    (2004-12) Koshy, P.K.; Sosamma, V.K.
    The burrowing nematode. Radopholus similis causes serious damage to coconut. Lesions and rotting of roots, defoliation and poor yield are the symptoms due to this nematode attack. Though the application of ncrnaticidcs is erfectivc in reducing the nematode population, these chemical pesticides dcs~roy the beneficial soil fauna. Vesicular Arbuscular Mycorrhizal (VAM) fungi can protect the coconut seedlings from nematode invasion. Investigation was carried out for three years (1994-1998) to assess the effect of biocontrol agents (BCA) namely Pasteuria penetrans, Paecilomyces lilacinus and Vesicular Arbuscular Mycorrhizal fungi on the growth of coconut seedlings infested with R. similis. The results showed that application of these biocontrol agents reduced the nematode multiplication significantly. while ameliorating the ill effects caused by the nematode. These biohontrol agents were more effective when they were applied together compared to their individual applications. Prior protection of the plants with BCAs either individually or in combination was better compared to simultaneous inoculation with the nematode. P. penetrans and P. lilacinus suppressed the nematode population effectively also under field conditions. Among VAM fungi, Acaulospora bireticulata, Glomus mosseae and G. fasciculatum multiplied well under field conditions. Since these organisms were found to multiply and survive under field conditions for more than three years, they need to be introduced to the root zone of perennial crops after every three to five years.
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    Effect of Radopholus similis on growth, flowering and yield of coconut
    (2007-02-08) Koshy, P.K.; Sosamma, V.K.
    The burrowing nematode, Radopholus similis is the most important nematode infecting coconut in South India. The pathogenic effects of R. similis on growth, flowering and yield of coconut cv. West Coast Tall was established under field conditions. Decrease in growth parameters of inoculated palms was corresponding to the increase in inoculum level and differed significantly from control. All the uninoculated palms came to flowering during 65-83 months after planting compared to 67-132 months in inoculated palms. However, the palms that received an initial inoculum of 1000 nematodes and above did not yield any nuts even after 11 years of planting. The control palms produced a total of 624 nuts compared to 186 nuts by palms that were inoculated initially with 100 nematodes. Final populations of nematodes did not differ significantly between treatments. The economic threshold level of R. similis on coconut (WCT) is 100 nematodes per seedling in loamy sand under the experimental conditions.