Yust, H.R., Fulton, R.A., & Nelson, H.D. 1951 Development and stability of resistance of California red scale to fumigation with hydrocyanic acid.. Journal of Economic Entomology 44(6): 833-838.

Notes: Resistant and nonresistant strains of California red scale, Aonidiella aurantii, have been maintained in the laboratory for over 15 years. 14 fumigations were repeated and subsequently suspended 27 generations. Most resistance was retained when fumigation was discontinued.