A slug, Arion ater, has become abundant in western Washington since its presence in the Pacific Northwest was first recognized in 1942. Its known distribution extends from Marion County, Oregon, through w. Washington into British Columbia. Observations indicate that there is 1 generation annually, and eggs are laid during late summer and early fall. The winter is passed either as eggs or very small larvae. On fallow ground metal-dehyde in pellet form combined with a bran carrier was more attractive to the slugs than a dust formulation. In the absence of rain the pelleted bait appeared effective for a longer time than the dust. Under garden conditions the bait was comparatively ineffective as the plant growth appeared more attractive to the slugs. The dust applied as bands in locations where the slugs would cross was very effective in garden conditions.