Meeting Abstract
Phasmarhabditis hermaphrodita is a parasitic nematode commercially available as a slug biopesticide (Nemaslug® ) in 14 European countries and was recently discovered in California. Two undescribed isolates of Phasmarhabditis, EM434 and DF5056, were recovered separately from unknown earthworm species in New York. This study aimed to characterize these two isolates and determine their effects on a range of nontarget earthworm species. Both were characterized by sequencing the mitochondrial cytochrome c oxidase 1 gene (CO1) using primers CO1-F1 and CO1-R2. The CO1 is often used as the standard barcode for almost all animal groups. The COI of DF5056 (two females) and EM434 (four females) consisted of 658 identical base pairs, however, NCBI BLAST comparison revealed that these sequences are unique. Infectivity of EM434 and DF5056 was tested on three nontarget earthworm species Eisenia hortensis, E. fetida, and Lumbricus terrestris; and on invasive slugs: Deroceras reticulatum and Lehmannia valentiana, using the Nemaslug® recommended dose of 30IJ/sq cm and a higher dose of 150IJ/sq cm. Preliminary studies showed that EM434, at both rates, infected and caused mortality on susceptible D. reticulatum and L. valentiana, but not on the three earthworm species tested. The same tests were repeated using DF5056, resulting in the mortality of two non-target earthworm species, Eisenia hortensis and E. fetida, and the two slug species. Preliminary results suggest DF5056 is more virulent than EM434.
