Contact toxicities of nine insecticides (four organ phosphorous insecticides and five pyrethroids) were tested on crawlers of a striped pine scale, Toumeyella pini (King). Organ phosphorous insecticides were more toxic than pyrethroids. Chlorpyrifos was the most toxic, and fenvalerate was the least toxic. Residual tests showed that the pyrethroid esfenvalerate lost its toxic effects at a slightly faster rate than the organ phosphorous insecticide azinphos-methyl. Low toxicity of the pyrethroids to crawlers may be partially responsible for the rapid build-up of T. pini in southern pine seed orchards.