Responsible for the cyclization of trans,trans-farnesyl diphosphate (FPP) to (+)-delta cadinene. (2E,6E)-farnesyl diphosphate = (1S,8aR)-delta-cadinene + diphosphate Binds 3 Mg(2+) ions per subunit. Secondary metabolite biosynthesis; terpenoid biosynthesis. By bacterial infection. The Asp-Asp-Xaa-Xaa-Asp/Glu (DDXXD/E) motif is important for the catalytic activity, presumably through binding to Mg(2+). Belongs to the terpene synthase family. Delta-cadinene synthase entry