Salama, H.S., El-Sherif, A.F., & Meirleire, H. de 1985 Soil nutrients affecting the population density of Parlatoria zizyphus (Lucas) and Icerya purchasi Mask. (Homopt. Coccoidea) on citrus seedlings.. Zeitschrift für Angewandte Entomologie 99: 471-476.

Notes: [Summary in German]. Excess amount of nitrogen or phosphorus caused an increase in population density of both pests; mentions three other coccoid species.