Feeding Activity and Survival of Slugs, Deroceras reticulatum, Exposed to the Rhabditid Nematode, Phasmarhabditis hermaphrodita: A Model of Dose Response

doi:10.1006/bcon.1999.0778

Biological Control

Volume 17, Issue 1, January 2000, Pages 73-81

https://doi.org/10.1006/bcon.1999.0778 Get rights and content

Abstract

The slug, Deroceras reticulatum (Stylommatophora: Limacidae), was exposed to different concentrations of infective dauer juveniles of the rhabditid nematode Phasmarhabditis hermaphrodita, in a two-stage bioassay, at 10°C. Slugs were exposed in groups of 10 or 12 to nematodes in plastic boxes filled with soil aggregates for 3 or 5 days and then transferred individually to petri dishes each containing a disk of Chinese cabbage leaf as food. Subsequently, slug food consumption and survival were measured for 10 to 13 days. Models were developed to describe the way that exposure to the nematode caused inhibition of slug feeding followed by death. Both effects were related to nematode concentrations and time after exposure to the nematode. Following exposure to high concentrations (300,000 dauer juveniles per box), slugs were killed rapidly, within a few days after the end of the exposure period. Following exposure to low concentrations of nematodes (7000 or 15,000 per box), substantial numbers of slugs survived until the end of the bioassay, but feeding activity by these slugs was strongly inhibited. It is suggested that inhibition of slug feeding is important for the success of this nematode as a biocontrol agent.

References (18)

M. Jaworska
Laboratory infection of slugs (Gastropoda: Pulmonata) with entomopathogenic nematodes (Rhabditida: Nematoda)
J. Invertebr. Pathol.
(1993)
M.J. Wilson et al.
Laboratory tests of the potential of entomopathogenic nematodes for the control of field slugs (Deroceras reticulatum)
J. Invertebr. Pathol.
(1994)
M.J. Wilson et al.
Slugs (Deroceras reticulatum and Arion ater agg.) avoid soil treated with the rhabditid nematode Phasmarhabditis hermaphrodita
Biol. Control
(1999)
R.A. Bedding
Large scale production, storage and transport of the insect parasitic nematodes Neoaplectana spp. and Heterorhabditis spp
Ann. Appl. Biol.
(1984)
D.J. Finney
Probit Analysis
(1971)
D.M. Glen et al.
Slug parasitic nematodes as biocontrol agents for slugs
Agro. Food Industry Hi-Tech.
(1997)
D.M. Glen et al.
Discovery and investigation of a novel nematode parasite for biological control of slugs
Proc. Brighton Crop Prot. Conf. Pests Dis.
(1994)
R.W. Payne et al.
GENSTAT 5 Reference Manual
(1987)

There are more references available in the full text version of this article.

Cited by (52)

Pathogenicity of wild and commercial Phasmarhabditis hermaphrodita exposed to the pestiferous slug Deroceras invadens
2020, Journal of Invertebrate Pathology
Citation Excerpt :
This is a common symptom of P. hermaphrodita infection and enhances the use of these nematodes as a biological control agent. Host feeding inhibition is also caused species that resist infection (Glen et al., 2000), such as juvenile A. lusitanicus (Grimm, 2002). Variation across exposure concentration, day and nematode strain was observed.
Many terrestrial gastropods are pestiferous and pose a significant threat to agriculture, horticulture and floriculture. They are usually controlled by metaldehyde based pellets but an alternative control method is the slug parasitic nematode Phasmarhabditis hermaphrodita, which has been formulated into a biological control agent (Nemaslug®) for use by farmers and gardeners to kill certain pestiferous slug species in 4–21 days. The current strain of P. hermaphrodita (called DMG0001) has been used in commercial production since 1994, but there is little information about the pathogenicity of wild strains of P. hermaphrodita towards slugs. Here, we exposed the pestiferous slug Deroceras invadens to nine wild isolated strains of P. hermaphrodita (DMG0002, DMG0003, DMG0005, DMG0006, DMG0007, DMG0008, DMG0009, DMG0010 and DMG0011) and the commercial strain (DMG0001) to three doses (0, 500 and 1000 nematodes per ml). Survival and feeding were recorded over 14 days. All wild P. hermaphrodita strains (other than DMG0010) and P. hermaphrodita (DMG0001), applied at 500 nematodes per ml, caused significant mortality to D. invadens compared to an uninfected control. Similarly, all P. hermaphrodita strains applied at 1000 nematodes per ml, caused significant mortality to D. invadens compared to an uninfected control. Overall, all wild P. hermaphrodita strains (other than DMG0011) caused significantly more mortality than P. hermaphrodita DMG0001 at one or both nematode concentrations. In summary, we have found some wild P. hermaphrodita strains were more virulent than P. hermaphrodita (DMG0001). Ultimately, these strains could potentially be developed as alternative, efficient biological control agents for use against slugs.
Molecular detection and quantification of slug parasitic nematodes from the soil and their hosts
2019, Journal of Invertebrate Pathology
Citation Excerpt :
Mollusc-parasitic nematodes (MPNs) are found in several nematode families including Alloionematidae, Cosmocercidae, Mermithidae and Rhabditidae (Půža et al., 2016); however, while entomopathogenic nematodes (EPNs) have been widely investigated as biological control agents and models in ecological studies, little attention has been given to nematodes that have the potential to control slugs. Currently only one species, Phasmarhabditis hermaphrodita (Rhabditidae), is commercially available as a slug biological control agent for mass-releases in gardens and cultivated fields (Speiser et al., 2001; Wilson et al., 1993; Glen et al., 2000; Barker and Efford, 2004; Wilson and Rae, 2015). Phasmarhabditis hermaphrodita is a bacterial-feeding nematode and a facultative parasite of terrestrial molluscs (Wilson, et al., 1993).
Terrestrial gastropod molluscs are widely distributed and are well known as pests of many types of plants that are notoriously difficult to control. Many species of nematodes are able to parasitize land snails and slugs, but few of them are lethal to their host. Species and/or populations of mollusc-parasitic nematodes (MPNs) that kill their hosts are promising for biological control purposes. The recent discovery of new nematode species of the genus Phasmarhabditis in Europe and the associations between Alloionema spp. and slugs are expanding the possibilities of using MPNs as control agents. However, very little is known about the distribution and ecology of these species. Using molecular techniques based on qPCR methods for quick identification and quantification of various species of MPN isolated directly from the soil or from infected hosts can assist in providing information on their presence and persistence, as well as the composition of natural assemblages. Here, we developed new primers and probes for five species of the genus Phasmarhabditis and one species of the genus Alloionema. We employed these novel molecular techniques and implemented a published molecular set to detect MPN presence in soil samples coming from natural and agricultural areas in Switzerland. We also developed a method that allows the detection and quantification of Phasmarhabditis hermaphrodita directly from the tissues of their slug host in a laboratory experiment. The new molecular approaches were optimized to a satisfactory limit of detection of the species, with only few cross-amplifications with closely related species in late cycles (>32). Using these tools, we detected MPNs in 7.5% of sampled sites, corresponding to forest areas (P. hermaphrodita and Alloionema appendiculatum) and wheat-oriented agricultural areas (Phasmarhabditis bohemica). Moreover, we confirmed that the method can be used to detect the presence of P. hermaphrodita inside slug hosts, with more detections in the susceptible slug Deroceras larvae compared to the resistant Arion vulgaris. These primers/probe sets provide a novel and quick tool to identify MPNs from soil samples and infected slugs without having to culture and retrieve all nematode life stages, as well as a new tool to unravel the ecology of nematode-slug complexes.
Susceptibility of the Giant African snail (Achatina fulica) exposed to the gastropod parasitic nematode Phasmarhabditis hermaphrodita
2015, Journal of Invertebrate Pathology
Citation Excerpt :
For example H. aspersa juveniles are susceptible to P. hermaphrodita but adults are resistant (Glen et al., 1996). We sought to understand whether young stages of A. fulica would be susceptible to P. hermaphrodita applied at two different doses, as well as investigating whether it would reduce feeding and cause defects in weight gain, a commonly observed symptom of infection in slugs (e.g. Glen et al., 2000b). We also exposed the slug Deroceras panoramitanum to assess the virulence of P. hermaphrodita to compare to A. fulica.
The Giant African snail (Achatina fulica) is a major pest in tropical countries. Current control methods involve the use of slug pellets (metaldehyde) but they are ineffective, therefore new methods of control are needed. We investigated whether A. fulica is susceptible to the gastropod parasitic nematode Phasmarhabditis hermaphrodita, which has been developed as a biological control agent for slugs and snails in northern Europe. We exposed A. fulica to P. hermaphrodita applied at 30 and 150 nematodes per cm² for 70 days and also assessed feeding inhibition and changes in snail weight. We show that unlike the susceptible slug species Deroceras panormitanum, which is killed less than 30 days of exposure to P. hermaphrodita, A. fulica is remarkably resistant to the nematode at both doses. Also P. hermaphrodita does not reduce feeding in A. fulica nor did it have any effect on weight gain over 70 days. Upon dissection of infected A. fulica we found that hundreds of P. hermaphrodita had been encapsulated, trapped and killed in the snail’s shell. We found that A. fulica is able to begin encapsulating P. hermaphrodita after just 3 days of exposure and the numbers of nematodes encapsulated increased over time. Taken together, we have shown that A. fulica is highly resistant to P. hermaphrodita, which could be due to an immune response dependent on the snail shell to encapsulate and kill invading parasitic nematodes.
Toxicity of methomyl, copper hydroxide and urea fertilizer on some land snails
2014, Annals of Agricultural Sciences
Citation Excerpt :
The terrestrial gastropod mollusks; snails and slugs, are serious pests attacking the vegetations including vegetables, horticultural plants and field crops in the most areas of Egypt. The fruits and vegetables get poor marketing ratings with reduced value (El-Okda, 1980; Glen and Wilson, 1997; Glen et al., 2000). Among the most serious land snails in Egypt, the brown garden snail, Eobania vermiculata (Müller), and the white snail, Theba pisana (Müller).
Terrestrial gastropods have become important economic pests attacking various vegetations in Egypt. According to this study, the molluscicidal activity of methomyl, urea, and copper hydroxide against the brown garden snail Eobania vermiculata and the small white garden snail, Theba pisana was investigated.
The obtained results indicated that copper hydroxide was the most toxic compound against E. vermiculata followed by methomyl and urea after 72 h of evaluation where LC₅₀ values were 3.31%, 3.75% and 40.88%, respectively. Methomyl was also the most toxic compound when it was tested against T. pisana followed by copper hydroxide followed by urea. The LC₅₀ values were 3.76%, 4.63% and 40.13%, with respect. The brown garden snail was more susceptible to copper hydroxide and methomyl than the second one. There was no difference in the susceptibility of the two tested snails to urea. The toxicity of the compounds was enhanced as increasing the exposure time. This study showed that the land snails may be controlled using urea fertilizer at concentration of 8%, to give % mortality in a range of (67–100)%.
Distribution and incidence of Leidyula moreleti and Sarasinula plebeia (Soleolifera: Veronicellidae), slug pests in the main producing region of vanilla in Mexico
2014, Revista Mexicana de Biodiversidad
Para conocer la distribución, incidencia del daño y especies de plaga de babosas en el cultivo de vainilla; se muestrearon 22 localidades de 9 municipios en 2 estados productores de vainilla en México. Se determinó la incidencia del daño por la plaga en el cultivo y se identificaron las especies presentes. En el 100% de las localidades muestreadas predominó la especie Leidyula moreleti y, en menor proporción se encontró a Sarasinula plebeia (31.8%), ambas mostrando incidencias en el cultivo que oscilan entre el 11 y 89%.
In order to know the distribution, incidence of crop damage and species pest of slugs, 22 locations were sampled in 9 municipalities in 2 vanilla producing states in Mexico. The incidence of damage by the pest in the cultivation was determined and the species were identified. Leidyula moreleti is the main slug found in 100% of the sampled locations and Sarasinula plebeia was found in smaller proportion (31.8%), both showing incidences ranging between 11 and 89%.
Pathogens and parasites of terrestrial molluscs
2012, Manual of Techniques in Invertebrate Pathology

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Biological Control

Abstract

References (18)

Laboratory infection of slugs (Gastropoda: Pulmonata) with entomopathogenic nematodes (Rhabditida: Nematoda)

J. Invertebr. Pathol.

Laboratory tests of the potential of entomopathogenic nematodes for the control of field slugs (Deroceras reticulatum)

J. Invertebr. Pathol.

Slugs (Deroceras reticulatum and Arion ater agg.) avoid soil treated with the rhabditid nematode Phasmarhabditis hermaphrodita

Biol. Control

Large scale production, storage and transport of the insect parasitic nematodes Neoaplectana spp. and Heterorhabditis spp

Ann. Appl. Biol.

Probit Analysis

Slug parasitic nematodes as biocontrol agents for slugs

Agro. Food Industry Hi-Tech.

Discovery and investigation of a novel nematode parasite for biological control of slugs

Proc. Brighton Crop Prot. Conf. Pests Dis.

GENSTAT 5 Reference Manual

Cited by (52)

Pathogenicity of wild and commercial Phasmarhabditis hermaphrodita exposed to the pestiferous slug Deroceras invadens

Molecular detection and quantification of slug parasitic nematodes from the soil and their hosts

Susceptibility of the Giant African snail (Achatina fulica) exposed to the gastropod parasitic nematode Phasmarhabditis hermaphrodita

Toxicity of methomyl, copper hydroxide and urea fertilizer on some land snails

Distribution and incidence of Leidyula moreleti and Sarasinula plebeia (Soleolifera: Veronicellidae), slug pests in the main producing region of vanilla in Mexico

Pathogens and parasites of terrestrial molluscs

Regular ArticleFeeding Activity and Survival of Slugs, Deroceras reticulatum, Exposed to the Rhabditid Nematode, Phasmarhabditis hermaphrodita: A Model of Dose Response

Abstract

J. Invertebr. Pathol.

J. Invertebr. Pathol.

Biol. Control

Large scale production, storage and transport of the insect parasitic nematodes Neoaplectana spp. and Heterorhabditis spp

Ann. Appl. Biol.

Probit Analysis

Slug parasitic nematodes as biocontrol agents for slugs

Agro. Food Industry Hi-Tech.

Discovery and investigation of a novel nematode parasite for biological control of slugs

Proc. Brighton Crop Prot. Conf. Pests Dis.

GENSTAT 5 Reference Manual

Regular Article
Feeding Activity and Survival of Slugs, Deroceras reticulatum, Exposed to the Rhabditid Nematode, Phasmarhabditis hermaphrodita: A Model of Dose Response