Change of abundance of arthropods in pine forests caused by aerial insecticide spray.

As pine wilt disease (PWD) spread rapidly throughout the Republic of Korea, pine stands were subjected to insecticide spraying that was gradually increased, which raised concerns regarding the negative impact of insecticides sprayed on nontarget organisms of pine forests. This study aims to estimate the changes in the abundance of arthropods caused by long-term insecticide spraying common in PWD-infected forests. Four pine stands were selected as sprayed and unsprayed sites in two locations in the southern regions of Busan and Gyongnam-do, showing the peaks of PWD epidemics. Beatings, sweepings, and pitfall trappings were used for collecting arthropods at the crown, undergrowth, and ground for 4 years, starting in May 2001. Long-term effects caused by yearly repeated insecticide treatments were not found to be related to changes in the abundance of arthropods, but short-term impacts within a year showed different influences according to habitats and functional groups.