Observations on the biology of Parthenolecanium rufulum in northeastern Italy, with a redescription of the first and second instar females

This paper presents some observations on the life history, phenology and morphology of Parthenolecanium rufulum (Cockerell), a Palaearctic soft scale species, widely distributed in European countries and especially common on Quercus. The study was carried out in North-eastern Italy on Quercus robur trees between July 2006 to June 2008. P. rufulum has one generation/year and overwinters as the 2nd-instar nymph. Moulting to adult female occurs from mid April onwards. Egg-laying occurs between late April and late May. Egg hatching occurs from the end of May. First-instar nymphs settle on the under surface of the leaves and moult to 2nd-instar nymphs in August. Starting from mid September, the 2nd-instar nymphs gradually migrate from the leaves to the twigs to overwinter. This migration is completed during the first 10 days of December. The pattern of phenology in Italy is about a month earlier than in Central Europe. The 1st- and 2nd-instar females of P. rufulum are also redescribed and illustrated; no males were noted and reproduction was parthenogenetic. In addition, some observations on the predator Anthribus nebulosus Forster (Coleoptera: Anthribidae) are reported.