MILAN, April 30 (Reuters) - Revenues at Ermenegildo Zegna rose 7.4% on an organic basis in the first quarter, above market expectations, thanks to solid growth in the Americas, the Italian luxury group said on Thursday.

o Revenues totalled 470.2 million euros ($549.38 million), above the 464 million euros expected by analysts according to Visible Alpha.

o Organic figures are calculated at constant exchange rates and exclude acquisitions and disposals.

o At current exchange rates the revenues increase was equal to 2.5% year on year, due mainly to the weaker dollar.

o Revenues grew 17.5% organically in the Americas and 5.3% in the greater China region.

o Revenues were driven by direct-to-consumer sales, while the wholesale channel posted a 17% decline.

($1 = 0.8559 euros)

(Reporting by Elisa Anzolin, editing by Gavin Jones)