Nel, J.J.C., De Lange, L., & Van Ark, H. 1979 Resistance of citrus red scale, Aonidiella aurantii (Mask.), to insecticides.. Journal of the Entomological Society of Southern Africa 42: 275-281.

Notes: This scale found to be resistant to parathion and to a varying degree cross-resistant to a number of other organophosphates normally used on citrus.