Terpene cyclase that catalyzes the cyclization of farnesyl diphosphate (FPP) to various sesquiterpenes, including alpha-muurolene, gamma-muurolene, alpha-selinene, beta-selinene, delta-cadinene, alpha-cadinol and delta-cadinol (PubMed:32233445). Delta-cadinene is the major product of Agr1 (PubMed:32233445). (2E,6E)-farnesyl diphosphate = delta-cadinene + diphosphate (2E,6E)-farnesyl diphosphate = alpha-muurolene + diphosphate (2E,6E)-farnesyl diphosphate = diphosphate + gamma-muurolene (2E,6E)-farnesyl diphosphate = alpha-selinene + diphosphate The DDXXD motif is important for the catalytic activity, presumably through binding to Mg(2+). Belongs to the terpene synthase family.