Occurrence of entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) in British soils

Abstract

SUMMARYSoil from 403 hedgerow, roadside verge, woodland, heathland or field sites was assessed for presence of entomopathogenic rhabditid nematodes with aGalleria larva baiting technique. Steinernematids were recovered from 48 % of the sites but only one site yielded Heterorhabditis sp. The species recovered most frequently was Steinernema bibionis (Bovien). Another unidentified Steinernema sp. was also isolated. Prevalence of steinernematids in the different types of habitat formed continuum so that roadside verges harboured them most often while heathland sites yielded them least often. Mean soil temperatures at 5 cm were about 15 °C in fields and verges, 13 °C in hedgerows and heathland and 12 °C in woodland. Prevalence of the nematodes varied in different parts of Britain and was influenced by soil type. They were associated with calcareous soils, especially those with a calcareous subsoil horizon. Soils which are periodically or seasonally water-logged were suitable. Soils enriched by humus and hence high in organic matter frequently harboured the nematodes and some suitable soils had significant clay contents or subsoils high in clay. It appears that the two steinernematids are relatively unspecialized species, occurring in diverse habitats and soil types and are adapted to cooler temperatures.

A survey of entomopathogenic nematodes of the families Steinernematidae and Heterorhabditidae (Nematoda: Rhabditida) in the north-west of Iran

“…Brown and Gaugler (1997) demonstrated that drought can markedly delay EPN emergence from host cadavers. There is some evidence of seasonality of occurrence in different EPN surveys (Mráček, 1980;Akhurst & Bedding, 1986;Blackshaw, 1988;Hominick & Briscoe, 1990). By contrast, Campbell et al (1995) and Glazer (1996) reported an absence of seasonal fluctuation in EPN densities.…”

“…However, biotic and abiotic factors cause the distribution EPN to differ across different regions. Factors such as soil texture, temperature and host availability are thought to be important in determining their distribution (Hominick & Briscoe, 1990;Griffin et al, 1991;Stock et al, 1999).…”

Occurrence and distribution of the entomopathogenic nematodes Steinernema spp. and Heterorhabditis indica in Indonesia

“…Both genera have global distributions and numerous surveys have documented their occurrence in Australia (Akhurst & Bedding, 1986), Europe (e.g. Mráček, 1980;Vänninen et al, 1989;Hominick & Briscoe, 1990;Griffin et al, 1991) and the Americas (e.g. Mráček & Webster, 1993;Liu & Berry, 1995).…”

Distribution & Preference of Entamopathogenic Bacteria across Different Soils of Karnataka

“…Dead larvae are washed in distilled water and put on White's trap for extraction or dissected out to see the presence of nematodes. The coloration of dead larvae gives some indication about the presence of EPNs (Hominick and Briscoe, 1990). Annual medium temperature and rainfall had little association with the presence of nematode, Heterorhabditis indicus isolated from soils in Tamil Nadu (Poinar et al, 1992).…”