Abstract
To examine the applicability of parasitic nematodes derived from the wood-boring insects as a biological control agent of M. alternatus, we investigated the prevalence of a species of parasitic nematode in Tomicus piniperda adults caught in the field. Among the 37 male and female adults of T. piniperda dissected, 31 (83.8 %) harbored parasitic nematodes in their hemocoels, with a maximum number of 132. We identified the parasitic nematode as Parasitorhabditis sp. via morphological observation of the adult nematodes. One to 123 nematodes originated from the 13 T. piniperda were incubated with each of the 13 mature M. alternatus larvae in a 6 cm petri dish. Most of the larvae pupated and emerged normally; however, two larvae did not pupate for 90 incubation days and one larva died as a pupa. No nematodes were detected in any of the 13 M. alternatus tested. However, the nematodes used in this study may not have been in a developmental stage suitable for invading into the host’s body. Hence, further studies, such as confirmation of infective stage of the nematode and inoculating them to the beetle, and selection of vulnerable stage(s) of beetle to the nematode, are needed to accurately estimate the nematode’s parasitic effect on M. alternatus.
https://ror.org/044bma518 
