Del Bene, G. 1991 A contribution to the knowledge of Parthenolecanium pomeranicum, new record (Kaw.): A Coccidae new to Italy.. Redia 74(1): 1-14.

Notes: This paper indicates the presence of scale insects of the genus Parthenolecanium in nursery gardens in Pistoia: P. pomeranicum (Kaw.) on the yew, and P. rufulum (Ck.) and P. corni (Bouche) on Gleditschia triacanthos. P. pomeranicum, monophagous on yews, is reported for the first time in Italy: as well as information on its taxonomy and distribution; notes given on morphology, and in particular on the characteristics that distinguish it from P. corni. P. pomeranicum on the yew and P. corni on Gleditschia triacanthos; reproduction by parthenogenesis, one generation a year; overwinters as second instar larvae. The P. pomeranicum second instar larvae moult in April: males are very rare, and females lay 60-240 eggs in June. The first instar larvae spread over both sides of the newly formed leaves, shows a preference for the underside. The first moult occurs in the middle of August, and by October there is a partial migration to the twigs. Consequently the degree of leaf infestation decreases from June-July (max. 41 1st instar larvae/leaf) and in the winter it is difficult to find more than 1-2 2nd instar larvae/leaf. P. corni's biological cycle differs only slightly: the appearance of females is more gradual, and the ovipositing period is longer, the number of eggs per female higher (800), and the newly-hatched larvae attach themselves only to the lower side of the leaf; moreover, the pre-winter migration from the leaves to the branches is complete. In Tuscany P. pomeranicum is not attacked by any of the species acknowledged as its natural enemies in Central European countries. An endoparasite of the Coccophaghus Westw. genus has been found on P. corni.