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    Persistence of Four Heterorhabditis spp. Isolates in Soil: Role of Lipid Reserves1


    Hasset, B. and Downes, Martin and Griffin, Christine (2002) Persistence of Four Heterorhabditis spp. Isolates in Soil: Role of Lipid Reserves1. Journal of Nematology, 34 (2). pp. 151-158. ISSN 0022-300X

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    Abstract

    Infective juveniles of four Heterorhabditis isolates (H. bacteriophora HI, H. megidis UK211 and HF85, and H. downesi M245) were stored in moist (pF 1.7) and dry (pF 3.3) loam soil at 20°C for up to 141 days. Survival, assessed by the number of nematodes extracted by centrifugal flotation, declined over time, reaching fewer than 18% alive by day 141 for all but one treatment (H. bacteriophora HI in dry soil). The infectivity of nematodes in soil for Tenebrio molitor also declined over time, roughly in accordance with the decline in numbers of nematodes. Energy reserves of extracted nematodes were assessed by image analysis densitometry. There were differences among isolates both in survival and in the depletion of reserves, and there was a significant correlation between these two parameters, suggesting that the extent to which energy reserves are depleted affects survival or that a common factor influences both. However, significant nematode mortality occurred while levels of reserves remained high, and the maximum reduction in utilizable body content for any treatment was 51%, well above starvation level. Therefore, the decline in numbers of living nematodes and the reduced nematode infectivity in soil cannot directly result from starvation of the nematodes. Survival and infectivity declined more rapidly in moist than in dry soil; one isolate, H. downesi M245, was less affected by soil moisture content than the other three isolates.

    Item Type: Article
    Keywords: energy reserve, entomopathogenic nematode, Heterorhabditis bacteriophora; Heterorhabditis downesi; Heterorhabditis megidis; infectivity; persistence; soil baiting; starvation; survival;
    Academic Unit: Faculty of Science and Engineering > Biology
    Item ID: 7541
    Depositing User: Dr. Christine Griffin
    Date Deposited: 19 Oct 2016 14:45
    Journal or Publication Title: Journal of Nematology
    Publisher: The Society of Nematologists
    Refereed: Yes
    URI:

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