Elmer, H.S., Ewart, W.H., & Carman, G.E. 1951 Abnormal increase of Coccus hesperidum in citrus groves treated with parathion.. Journal of Economic Entomology 44(4): 593-597.

Notes: This soft (brown) scale is distributed throughout the world and feeds on a wide variety of plants, both in the greenhouse and out doors. Usually it's only a minor pest of citrus in California because of highly effective parasites. In 1947 however, it became a major pest in certain groves after experimental applications of parathion for the control of yellow scale Aonidiella citrina and citricola scale, C. pseudomagnoliarum. Other scales mentioned include Lecanium corni, L. nigrofasciatum, L. fletcheri, Icerya purchasi and Saissetia oleae.