Abstract
The cypress bark moth, Epinotia granitalis (Butler), is a serious insect pest of the Japanese cedar, Cryptomeria japonica. Light traps have been used for monitoring the number of moths in forests. However, whether the number of moths captured by light traps reflects the number of moths emerged has not been examined yet. Since the last instar larvae of the moth leave feeding scars on the trunks, the number of scars was considered to be a good index of the number of moths emerged. To verify this assumption, I analyzed the correlation of the number of feeding scars on the trunks of 20 cedar trees in two different forests with the number of moths captured by the light trap placed in the same two forests for 6∼7 years. The results showed a strong positive correlation between the number of moths captured by the light trap and the number of feeding scars in both forests indicating that the number of moths captured by the light trap reflects the number of moths emerged. Thus, the light trap is a valuable tool to monitor the number of cypress bark moths emerged.
