Sesquiterpene synthase involved in the biosynthesis of volatile compounds that contribute to the characteristic flavors of black pepper (PubMed:29248443). Mediates the conversion of (2E,6E)-farnesyl diphosphate (FPP) into alpha-cadinene, delta-cadinene and delta-cadinol (PubMed:29248443). (2E,6E)-farnesyl diphosphate = delta-cadinene + diphosphate (2E,6E)-farnesyl diphosphate = alpha-cadinene + diphosphate (2E,6E)-farnesyl diphosphate + H2O = delta-cadinol + diphosphate Binds 3 Mg(2+) or Mn(2+) ions per subunit. kcat is 0.694 sec(-1) with (2E,6E)-farnesyl diphosphate as substrate. Secondary metabolite biosynthesis; terpenoid biosynthesis. Expressed at low levels in stems, leaves, roots and fruits. 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. Tpsa subfamily.