PINE WEEVIL ABUNDANCE ON CLEAR-CUTTINGS OF DIFFERENT AGES - A 6-YEAR STUDY USING PITFALL TRAPS

Patterns of seasonal and yearly variation in the abundance of the pine weevil, Hylobius abietis (L.) (Coleoptera: Curculionidae), were deter mined on clear-cuttings of various age in southern Sweden. New clear-c uttings were established during each of five consecutive years, and th e numbers of weevils caught in pitfall traps baited with alpha-pinene and ethanol were recorded weekly during the season for up to 6 yrs on these areas. In total, 74 281 weevils were trapped. On fresh clear-cut tings, the catches increased drastically once migrating weevils had ar rived in spring. Catches peaked in May and July but were lower in June , when oviposition underground is most intense. The catches declined s uddenly in the middle of August, coincident with the weevils becoming post-reproductive. On older clear-cuttings, most weevils were caught b efore migration in spring; thereafter the catches gradually decreased from June to September. Pine weevils were even abundant on 5-yr-old cl ear-cuttings. Relationships between trap catch and weevil-induced seed ling mortality were examined on fresh clear-cuttings and on the same a reas over the following 3 yrs. A significant relationship between thes e two variables existed only for the 2-yr-old clear-cuttings. Therefor e, trapping data alone appear to be insufficient in forecasting seedli ng damage.