Fate and persistence of insecticides in pine forests by eco-chemical monitoring

Pine forests in the North-east German Plain (Brandenburg) are typical areas for outbreaks of insect pests, like Dendrolimus pini (L.). The reasons for the landscape-defining cultivation of Pinus sylvestris L. are mainly climatic and historical. In interest of forest management, it is important to prevent large-scale larvae feeding and defoliation damages. Therefore, insecticides can be applied to the crown area of pine forests, if a high risk of forest damage is predicted after using monitoring methods. According to Paragraph 18 of the German Plant Protection Act (PflSchG), the aerial application with helicopter is possible. Ecological-chemical monitoring can generate data on the fate and persistence of the plant protection products respectively incorporated active substances applied in the environment, which can be used to estimate the effects on the ecosystem. In the present study, aerial forest protection measures were monitored and further field trials were carried out to determine the active substance levels of tebufenozide and lambda-cyhalothrin on different compartments (insect pests/non-target organisms, pine needles and forest soil) in time-dependent sampling before and after application. The results of the trace analysis and exposure estimation allowed an evaluation of the exposure situation in pine forests.