Abstract
We investigated the attacks by the oak borer to living oak trees since 1995 to 1998 in the east area of Tottori Prefecture, where the mass mortality of oak trees have been revealed since 1994. The attacks aggregated some trees within a short period and ceased within 1-3 years since begining of the attacks. These suggested that the reproductive rate of the oak borer declined soon by the deterioration of the host quality, so we predicted that the mass mortality would cease in a few years.
