Bulletin of Insectology 66 (2): 209-211, 2013 ISSN 1721-8861 First record of Phenacoccus defectus in Italy, with comments on Phenacoccus solani and Phenacoccus solenopsis Giuseppina PELLIZZARI 1 , Francesco PORCELLI 2 1 Dipartimento di Agronomia, Animali, Alimenti, Risorse Naturali e Ambiente - DAFNAE, Università di Padova, Legnaro, Italy 2 Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti - DiSSPA, sez. Entomologia e Zoologia, Università di Bari Aldo Moro, Bari, Italy Abstract The alien mealybug Phenacoccus defectus Ferris (Rhynchota Pseudococcidae) is recorded in Italy for the first time. The species was first starting from 2009 on potted plants of Aeonium arboreum, Echeveria sp., Sedum palmeri, Sempervivum tectorum (Cras- sulaceae) and Senecio citriformis (Asteraceae). Comments on the morphologically very similar Phenacoccus solani Ferris and Phenacoccus solenopsis Tinsley are discussed. Key words: Pseudococcidae, mealybugs, Crassulaceae. Introduction The import and trade of succulent plants have led to the introduction to Italy of several alien mealybug species that have spread in greenhouses and private collections, namely Delottococcus euphorbiae (Ezzat et McCon- nell), Hypogeococcus pungens Granara de Willink, Spi- lococcus mamillariae (Bouche), Trochiscococcus speci- osus (De Lotto), Vryburgia brevicruris (McKenzie), and Vryburgia rimariae Tranfaglia (Rhynchota Pseudococ- cidae) (Tranfaglia, 1981; Longo et al., 1989; Williams and Pellizzari, 1997; Pellizzari, 2010). Besides the above recorded species, the North American mealybug Phenacoccus defectus Ferris was detected several times, from April 2009 onwards, on ornamental potted Crassu- laceae in a private collection in the town of Padova (north-eastern Italy). No chemical control measures were taken by the owner, whose action was just to eliminate highly infested plants. According to the owner, the only additions to the collection were some succulents imported one year before (2008) from Bordighera in the Liguria region (north-western Italy). Materials and methods Specimens were mounted according to the procedures of Ben-Dov and Hodgson (1997). Specimen depository: The Scientific Museums of the University of Padova (Italy), Department DAFNAE. Discussion P. defectus was first recorded in Europe in Great Britain, in 1997 on succulent plants in private collections and it has since been found indoors at a botanical collection on Echeveria plants and on succulent plants outdoors during the summer of 2007 (Malumphy, 1997; Malumphy et al., 2013). In 2006 it was recorded on Euphorbia in a green- house in South France (Nice) (Germain and Matile Fer- rero, 2006). In both cases the authors report that the plants were originally imported from Italy (Malumphy et al., 2013; Germain, 2005 in litteris). P. defectus is a North American species, described on specimens collected on Eriophyllum confertiflorum (As- teraceae) in California, Santa Clara County (Ferris, 1950). It was recorded later in several localities in Cali- fornia (McKenzie, 1967), in Mexico (Williams and Granara de Willink, 1992) and recently in Japan (Ta- naka and Uesato, 2012). It develops on plants of Acan- thaceae, Asteraceae, Chenopodiaceae, Crassulaceae, Euphorbiaceae, Fabaceae, Hydrophyllaceae, Lamiaceae, Poaceae and Polygonaceae. With regard to Crassu- laceae, it was recorded on Echeveria longissima, Sem- pervivum tectorum (McKenzie 1967), Sedum palmeri (Williams and Granara da Willink, 1992), Crassula por- tulacea, Echeveria craigiana, E. lurida, E. recurvata, E. sessiliflora and Echeveria sp. (Malumphy, 1997). Malumphy (1997) reported the first biological obser- vation on this species: the females are parthenogenetic and ovoviviparous. The mealybugs feed on the growing part of the plant and excrete sticky honeydew; heavily infested plants eventually die. In Padova P. defectus was collected on Aeonium ar- boreum, Echeveria sp., Sedum palmeri, Sempervivum tectorum (Crassulaceae) and Senecio citriformis (As- teraceae). Infested plants are presently kept under glass at the Experimental Farm of the School of Agriculture, University of Padova, in order to study the biology of the mealybug. According to our first observation it is mainly dangerous to Sempervivum plants, which can die when highly infested. The mealybugs are well concealed in protected places as under the succulent leaves, near the stem or the crown and low infestations are easily over- looked. The mealybugs crawl actively from pot to pot and can spread rapidly. Sticky honeydew is excreted on infested plants, when population levels are high. Besides P. defectus, two other American Phenacoccus species, namely Phenacoccus solani Ferris and Phena- coccus solenopsis Tinsley, are recent invaders in coun- tries of the Mediterranean basin.