Publication Date:
2002-03-01
Description:
Larvae of the poplar and willow borer, Cryptorhynchus lapathi (L.), an exotic Eurasian weevil, bore into the stems of Salix and Populus spp. creating infection courts for pathogens and weakening stems to breakage. We conducted a survey to determine the distribution and prevalence of C. lapathi in British Columbia. The survey spanned five biogeoclimatic zones, 15 subzones, 45 locations, 135 sites, and 3360 trees. We found the still-expanding range of C. lapathi to have at least doubled since 1963. The weevil was present in 38 locations and 14 subzones, with prevalence of weevil-attacked trees significantly lower in cold than in warm subzones. A regression model based on number of months with mean temperature 〉10°C reliably described the proportions of attacked trees in the 15 subzones (r2 = 0.81) and predicts that [Formula: see text] 25% of willows in 58.1% of British Columbia could ultimately be infested. The number of individual weevils per tree and per stem and the intensity of attack were positively and either exponentially (per tree and per stem) or logistically (intensity of attack) related to the prevalence of attacked trees (r2 = 0.41, 0.36, and 0.75, respectively). As the prevalence and intensity of attack by C. lapathi in British Columbia increase, so may the ecological and economic impact of the weevil.
Print ISSN:
0045-5067
Electronic ISSN:
1208-6037
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
