Abstract
Japanese oak wilt (JOW) is an epidemic disease transmitted by an insect vector, the oak platypodid beetle Platypus quercivorus. Splitting a dead tree is one of the best approaches to prevent spreading JOW because this method is not only highly effective in the extermination of the beetles but also in the availability of infested trees for fuel. However, this approach has high costs for on-site work to prepare firewood and is restricted to the Quercus genus available for fuel. Here, we investigated whether the number of newly emerged adults decreased by leaving the split logs of the infested Quercus serrata and Lithocarpus edulis in the forest. The dead trees of both species were brought to the study site, each cut into 30 cm lengths. These logs were split in half and eighth, and intact logs were prepared. We placed these logs into each trap to collect adults and measured the weight of split logs to predict water contents. In Q. serrata, the number of adults in eighth-split logs significantly decreased than those of half-split logs and intact logs. The predicted water contents of eighth-split logs were significantly low compared with those of others. In L. edulis, the number of adults collected from half- and eighth-split logs significantly decreased than those of intact logs, but the predicted water contents were not different between half- and eighth-split logs. Our results indicated effective pest control even if at least eighth-split logs of both tree species were left on the forest floor.
