Abstract
The hibernation and aestivation sites of Dacne japonica and D. picta, serious pests of the Shiitake mushroom in cultivated field, were investigated. Adults of both species were found overwintering in crevices of the outer-barks of two dominant tree species in the field, Quercus serrata and Q. acuitissima. Comparatively they were abundant in the crevices between 10 to 20 cm in height above the ground. D. japonica adults aestivated at almost the same sites as they hibernated. These hibernating and aestivating beetles frequently were found dead at these sites.
