Christmas tree pests and weeds of different pests, most of which cause cosmetic damage to the trees, important in the Christmas tree industry. The balsam woolly adelgid ("Adelges picae") are small soft-bodied insects which attack the Fraser fir. The insects appear as white, woolly spots on the tree and are fatal to the fir if left untreated. The woolly adeligid was native to central Europe where it affected the silver fir; it was introduced to the United States, where it has no known native predators, before 1900. Balsam twig aphids ("Mindarus abietnus") are another type of tree pest which affects fir and spruce trees in
Fraser Canyon Gold Rush "humbug". Many returned to San Francisco. A continuing influx of newcomers replaced the disenchanted, with even more men storming the route of the Douglas Road to the upper part of Fraser Canyon around Lillooet; others got to the upper canyon via the Okanagan Trail and Similkameen Trail, and to the lower Canyon via the Whatcom Trail and the Skagit Trail. All these routes were technically illegal since the Governor required that entry to the colony to be made via Victoria, but thousands came overland anyway. Accurate numbers of miners, especially on the upper Fraser, are therefore difficult to reckon. During