Forest roadside sampling of larvae and adults of the western hemlock looper, Lambdina fiscellaria lugubrosa

The roadside sampling method, in which sampling is conducted along a road has the advantage that large areas can be quickly surveyed. The method is particularly useful for forest areas where accessibility to trees within a stand can be a problem. In this study, larvae and adults of the western hemlock looper were sampled along forest roads and the data were examined with spatial statistics. The results indicated spatial continuity of insect counts along the forest roads, although the range and magnitude varied significantly between years and among sites. At Sugar Lake Forest Road, larvae and adults were spatially dependent within a distance of 7.25 km. In the three Vancouver watersheds, a significant spatial autocorrelation of male adult counts occurred when traps were up to 3 km apart. In addition, insect densities along the roads were closely related to those within the stands. The implications of these results to the management of the western hemlock looper are discussed.