Grafton-Cardwell, E.E., Ouyang, Y., & Salse, J. 1998 Insecticide resistance and esterase enzyme variation in the California red scale (Homoptera: Diaspididae).. Journal of Economic Entomology 9: 812-819.

Notes: A population of California red scale, Aonidiella aurantii (Maskell), was found to be resistant to the organophosphates chlorpyrifos and methidathion, and to the carbamate carbaryl when compared with a susceptible population. The esterase inhibitor S,S,S-tributyl phosphorotrithioate increased chloropyrifos toxicity in the resistant population to a greater extent than in the susceptible population, suggesting that esterase enzymes were involved in chlorpyrifos, but not methidathion or carbaryl resistance. The esterase banding patterns of both populations were characterized using cellulose acetate electrophoresis. There was variation between sexes and stages of scale in the relative mobility, frequency of occurrence, and activity of the esterase bands. The data suggests that the EST-3 band is involved in insecticide resistance in California red scale and that the EST-3 band in nongravid 3rd-instar females could be used for a diagnostic test for resistance.