In Korea, two sawyer beetle species belonging to genus Monochamus are vectors that transmits the pine wood nematode. In this study, we surveyed the seasonal change of spatiotemporal distribution of Monochamus alternatus and Monochamus saltuarius. A total of 360 multi-funnel traps were placed in three different regions, such as Gapyeong, Yeongdeok, and Jeju. In M. saltuarius, we collected 1,496 individuals and 709 individuals in Gapyeong and Yeongdeok, respectively, and in M. alternatus 348 individuals and 113 individuals were collected in Jeju and Yeongdeok, respectively. We analysed their patterns in spatiotemporal distribution using by global spatial autocorrelation. In M. alternatus, spatially clustering on Jeju was observed in July and August, and M. saltuarius in a site of Gapyeong was clustered. These spatiotemporal distributions of two Monochamus species may be probably related to their behavior, such as maturation feeding and dead tree searching.

This study was conducted to examine the occurrence characteristics of pine trees infected by pine wood nematode in Gyeongsangbuk-do, Korea. Based on the GPS coordinate data of the infected trees at Yeongdeok-gun from 2013 to 2014 and at Andong-si in 2014, nearest neighbor analysis was conducted to analyze nearest distance between the infected trees. And the influence of geographical factors such as altitude, slope, and the distance from the road on the position of infected trees were identified. Our results showed that over 60% of the newly infected trees were found within 50m of the trees infected in previous year. Over 70% of infected trees occurred below 100m altitude in Yoeongdeok-gun whereas less 32% of total pine trees distributed below the altitude. 98% of the infected trees and 74% of total pine trees in Andong-si were found between 150 and 300m altitude, and altitudinal distribution of the infected trees was similar to that of pine forests. Only less 5% of infected trees found in the forests located below 5 degree of slope in Yeongdeok-gun whereas 18% of total pine trees existed in the areas. Over 50% of infected trees in the forests located from 10 to 20 degree of slope, and 47% of total pine trees were found in the forests located from 5 to 15 degree of slope. Most infected trees and total pine trees were found in the forests located below 15 degree of slope in Andong-si. Over 80% of the infected trees occurred within 1km of road in both study areas.