The Ontario Ministry of Food, Agriculture and Rural Affairs (OMAFRA) has issued a notice that beech scale crawlers are active now on large beech trees in southern Ontario forests, including in cottage country. Covered in a white, woolly mass, the adult females are easy to see. Although the scale insects do not kill the tree, the bark wounds they create facilitate the entry of beech bark disease which is very deadly.
For more information on this pest, see the OMAFRA information here.