Abstract
Tree damage by resinous disease of hinoki cypress and number of scars caused by hinoki bark moth (Epinotiagranitalis BUTLER) were investigated in two hinoki stands in Ibaraki Prefecture to see if there was any correlation between the occurrence of resinous disease and insect attack. The type of forest adjoining the hinoki stands was found to influence the number of trees affected by resinous disease and also the number of trees with moth damage. The hinoki bark moth is known to inhabit mature sugi forests. In a 35-yearold stand of hinoki, the occurrence of resinous disease was far greater in plots adjoining sugi forests than in plots adjoining broad-leaved tree forests. In a 5-yearold stand of hinoki forest surrounded by 3040yearold sugi forests, the number of scars caused by the hinoki bark moth were greater in peripheral plots near the sugi forests than in the central areas. The results of this study suggested that there is correlation between the occurrence of resinous disease and insect attack in hinoki trees, the insect damage allowing the pathogen causing resinous disease to enter the tree.
