Non-Susceptibility of EarthwormEiseniafetidato the Rhabditid NematodePhasmarhabditishermaphrodita, a Biocontrol Agent of Slugs

Abstract

The rhabditid nematode Phasmarhabditis hermaphrodita is a lethal parasite for slugs that is sold commercially in Europe under the trade name Nemaslug TM . We evaluated the effects of P. hermaphrodita on the earthworm Eisenia fetida (Savigny). Adults of E. fetida were exposed in one-liter glass beakers to P. hermaphrodita at three concentrations (1)/, 10)/ and 50 )/ of the field recommended rate of 3)/10 9 billion nematodes/ha) during a 14-day period in an artificial soil substrate. The average body weight, burrowing behavior, mortality and other clinical signals of the earthworms were recorded at 0, 7, and 14 days after exposure to the treatments. In addition, injured earthworms (posterior ends removed) were exposed to the 10)/ field recommended rate of the commercial formulation. Neither intact nor injured E. fetida showed susceptibility to the slug-parasitic nematode P. hermaphrodita during the 14 days of exposure even at concentrations 10 and 50 times higher than the label dose. However, the worms in the attenuated control (autoclaved formulation) had higher mortality and lost less weight compared to the other treatments. Under the conditions of the test, we conclude that the use of the commercially available strain of P. hermaphrodita is safe to E. fetida.

Mortality of the invasive white garden snail Theba pisana exposed to three US isolates of Phasmarhabditis spp (P. hermaphrodita, P. californica, and P. papillosa)

“…All three species of Phasmarhabditis used in this report were isolated from slugs recovered from nurseries and garden centers located in the state of California. In the case of P. hermaphrodita (Nemaslug 1), studies showed it does not cause mortality to some non-target organisms like Ariolimax columbianus Gould, 1851; Pomatias elegans Müller, 1774; Monacha cantiana Montagu, 1803; Eisenia fetida Savigny,1826; and Lumbricus terrestris Linnaeus, 1758 [44][45][46][47].…”

Novelties in Pest Control by Entomopathogenic and Mollusc- Parasitic Nematodes

“…Some other snails (Succinaea putris, Pomatias elegans, Cepaea nemoralis and others) can be infected with P. hermaphrodita but its effect on them is very low, if any. Negative effect on the earthworms Lumbricus terrestris and Eisenia foetida and others has never been found [134,135], and no effect was found also against insects Pterostichus melanarius, Zophobas morio or Galleria mellonella [136,137]. P. hermaphrodita is freely associated with many soil-dwelling bacteria [55,138], and some of them, for example, Stenotrophomonas maltophilia [42] can be occasionally dangerous for human, especially those with a weakened immunity system.…”

Biological control of terrestrial molluscs usingPhasmarhabditis hermaphrodita—progress and prospects

“…It does not kill US strains of the earthworms Lumbricus terrestris L 35. and Eisenia fetida (Savigny)36 or UK strains of L. terrestris, Eisenia hortensis (Michaelsen), E. fetida, Eisenia andrei Bouche, Dendrodrilus rubidus (Savigny) or the platyhelminth Arthurdendyus triangulatus (Dendy) (the New Zealand flatworm) 37. These results appear to contradict an earlier study in which L. terrestis were found parasitised by a ‘ Phasmarhabditis ‐like’ species in the USA,38 but it may be that the nematode isolated was not a Phasmarhabditis spp.…”