Plant Pathology Laboratory, Faculty of Agriculture, Aristotle University of Thessaloniki, Thessaloniki, Greece Transmission of Zucchini yellow mosaic virus by Colonizing and Non-colonizing Aphids in Greece and New Aphid Species Vectors of the Virus N. I. N. I. Katis Katis 1 , J. A. J. A. Tsitsipis Tsitsipis 2 , D. P. D. P. Lykouressis Lykouressis 3 , A. A. Papapanayotou Papapanayotou 1 , J. T. J. T. Margaritopoulos Margaritopoulos 2 , G. M. G. M. Kokinis Kokinis 1 , D. Ch. D. Ch. Perdikis Perdikis 3 and and I. N. I. N. Manoussopoulos Manoussopoulos 2 AuthorsÕ addresses: 1 Plant Pathology Laboratory, Faculty of Agriculture, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece; 2 Laboratory of Entomology and Agricultural Zoology, University of Thessaly, 384 46 Nea Ionia, Magnesia, Greece; 3 Laboratory of Agricultural Zoology and Entomology, Agricultural University of Athens, Iera Odos, 118 55 Athens, Greece (correspondence to N. I. Katis. E-mail: katis@agro.auth.gr) Received August 5, 2005; accepted January 11, 2006 Keywords: Zucchini yellow mosaic virus, non-persistent transmission, aphid vectors, cucurbits, Greece Abstract Nineteen aphid species were tested for their ability to transmit Zucchini yellow mosaic virus (ZYMV) from and to zucchini under laboratory conditions. Sixteen species were found to be new vectors of ZYMV (i.e. Aphis craccae, Aphis fabae, Aphis nerii, Aulacorthum solani, Brachycaudus cardui, Brevicoryne brassicae, Hy- alopterus pruni complex, Hyperomyzus lactucae, Mac- rosiphoniella sanborni, Macrosiphum rosae, Metopolophium dirhodum, Myzus cerasi, Rhopalosiphum maidis, R. padi, Semiaphis dauci and Sipha maydis). Their transmission efficiency by a single aphid was low (0.1–4.2%). Myzus persicae was used as a control and was the most efficient vector (41.1%, one aphid per plant). Hayhurstia atriplicis, Myzus ascalonicus and Si- tobion avenae did not transmit the virus. In four out of six new vectors assayed in arena tests for propensity estimation, propensity was higher than efficiency. Data from an experimental zucchini field in northern Greece revealed a high correlation between ZYMV spread and alatae of the vector species. The most abundant aphid vectors during 2 years experimentation were M. persi- cae, Aphis gossypii and Aphis spiraecola. The possible role of the 16 new and the previously known aphid vec- tors in the epidemiology of ZYMV was investigated using data of transmission efficiency combined with the captures of their alatae in the Greek net of a Rotham- sted type suction trap. Introduction Zucchini yellow mosaic virus (ZYMV; family Potyviri- dae, genus Potyvirus) affects cucurbit crops throughout the world (Lisa et al., 1981; Lecoq et al., 1983; Lese- mann et al., 1983; Provvidenti et al., 1984; Nameth et al., 1985; Desbiez and Lecoq, 1997). Yield losses in cantaloupe were particularly high when infection occurred before fruit set (Blua and Perring, 1989). Similar results were observed in zucchini Cucurbita pepo L. (Cucurbitaceae) when mechanical inoculation was made during 2–3-weeks period after transplanta- tion in experiments under cover (J. A. Tsitsipis et al., unpublished data). In Greece, the virus was first recor- ded in southern regions of the country in cucumber, Cucumis sativus L. (Cucurbitaceae) and zucchini crops (Kyriakopoulou and Varveri, 1991). ZYMV has since been regularly isolated from field-grown cucumber, zucchini, melon, Cucumis melo L. and watermelon [Citrulus lanatus (Thunb.)] all over the country and it has always been associated with considerable crop los- ses (A. Avgelis, personal communication; N. I. Katis, unpublished data). The role of ZYMV has become more important in cucurbit production as periodic epidemics have appeared throughout the country (Va- itsopoulos and Katis, 1993; Papavassiliou, 2000). ZYMV infects cucurbit plants and is transmitted non-persistently by many colonizing and non-colon- izing aphid species (Perring et al., 1992; Desbiez and Lecoq, 1997). In this mode of transmission (for reviews see Katis, 1989; Pirone and Perry, 2002) aphids transmit the viruses by short test probes, lasting a few seconds, to evaluate the suitability of the host plant during the host selection process. To date 10 aphid species of the family Aphididae have been reported as vectors of ZYMV: Aphis gos- sypii Glover (Lisa et al., 1981); Aphis craccivora Koch (Adlerz, 1987); Aphis spiraecola Patch (Lisa and Lecoq, 1984); Aphis middletonii Thomas (Adlerz, 1987); Acyrthosiphon kondoi Shinji (Perring et al., 1992); Acyrthosiphon pisum (Harris) (Adlerz, 1987); Lipaphis erysimi (Kaltebach) (Adlerz, 1987); Macrosip- hum euphorbiae (Thomas) (Lisa and Lecoq, 1984); Myzus persicae (Sulzer) (Adlerz, 1987) and one Uroleu- con species (Perring et al., 1992). Blackman and Eastop (2000) have reported more than 10 aphid species www.blackwell-synergy.com J. Phytopathology 154, 293–302 (2006) Ó 2006 The Authors Journal compilation Ó 2006 Blackwell Verlag, Berlin