Testing a new low-labour method for detecting the presence of Phasmarhabditis spp. in slugs in New Zealand

Abstract

Most studies on distribution ofPhasmarhabditisspp. in slugs use dissection of individual slugs, which is time-consuming. Here we use a technique modified from that used to collectPristionchusspp. nematodes from their beetle hosts. Slugs are decapitated and cadavers incubated for 1 week prior to examining for presence of adult nematodes. We compared the new technique with traditional dissection using field-collected untreated slugs, and slugs infected withPhasmarhabditis hermaphroditain the laboratory. There was no difference in the efficacy of the two techniques. We also used the new technique to study prevalence ofP. hermaphroditaat 22 New Zealand sites. We foundP. hermaphroditapresent at three sites andP. californicaat two other sites suggestingPhasmarhabditisspp. are relatively common in New Zealand.