Susceptibility of Norway spruce plantations to white pine weevil attacks in southern Quebec

Abstract

Annual levels of attack by the white pine weevil (Pissodesstrobi Peck) in 110 Norway spruce (Piceaabies (L.) Karst.) plantations of southern Quebec were measured. The relationships between levels of attack and site and stand characteristics were determined. In 1991, 84% of the plantations were affected by the weevil. Annual levels of attack increased from 2 to 25% of the trees between 1987 and 1991 for the 110 plantations. Drainage and site quality index influenced the levels of attack. On medium-textured soil ecosystems, plantations situated on imperfectly drained soils were significantly more affected (43%) than those on well-drained soils (11%). Plantations located on the most productive sites (site quality index 13–14 m at 25 years) were less affected (8%) than those on the least productive (7–8 m at 25 years) sites (34%). There was no significant correlation between plantation density and levels of attack. The results showed that the white pine weevil is one of the most damaging pests of Norway spruce plantations in southern Quebec. Norway spruce plantations should be monitored annually for damage detection. Appropriate sites should be selected for reforestation to maximize productivity and minimize insect damage.