Cressman, A.W., Munger, F., & Broadbent, B.M. 1953 Some factors influencing the effectiveness of parathion against California red scale.. Journal of Economic Entomology 46(6): 1070-1074.

Notes: Natural factors that are important in the efficient use of parathion alone and combined with oil for control of Aonidiella aurantii, were investigated in the field and laboratory in California between 1948 and 1952. Mortality of the scales after field sprays of parathion was lowest on the fruit, highest on the gray wood, and intermediate on the green twigs. The kills by oil plus parathion were nearly equal on all parts of the tree. Density of infestation and differences in temperature were also discussed.