Modelling the spiders ballooning effect on the vineyard ecology E. Venturino, M. Isaia, F. Bona, E. Issoglio, V. Triolo and G. Badino Math. Model. Nat. Phenom., 1 1 (2006) 133-155 Published online: 15 May 2008 DOI: 10.1051/mmnp:2006008