Two types of exogenous mortality factors, density-independent and density-dependent, were identified for the black vine weevil, Otiorhynchus sulcatus Fab., developing on container grown rhododendrons. The addition of the insecticide acephate, (O.S.- Dimethyl acetylphosphoramidothioate, Orthene®)75S) to the rhizosphere of rhododendrons in which larval O. sulcatus develop was categorized as a density-independent...