2014 Volume 18 Issue 4 Pages 95-104
Japanese oak wilt disease carried by Platypus quercivorus has been growing since the 1980s. Although climate conditions are sometimes mentioned as an explaining this expansion, there is no statistical analysis to support this notion. Given this, we examined the relationship between the annual number of killed oak trees and climate conditions with a single regression analysis that was based on the results of damage surveys conducted in Kyoto City and Maizuru City, Kyoto Prefecture. As a result, we found that, in both areas, there is a tendency for the number of killed oak trees to increase in line with increases in the maximum temperature during the coldest period (i.e., from January to February). Additionally, in Kyoto City, there is a tendency for damage to increase correspondingly with higher amounts of spring precipitation. Moreover, in Maizuru City, there is a tendency for the number of killed oak trees to increase correspondingly with increases in the number of days that have a low temperature of at least 20°C between June to July. However, results supporting the common opinion that high temperature and light rain in summer promote Japanese oak wilt disease were not obtained.
