  In this paper, we consider doubly warped product (DWP) Finsler manifolds with
some non-Riemannian curvature properties. First, we study Berwald and isotropic
mean Berwald DWP-Finsler manifolds. Then we prove that every proper Douglas
DWP-Finsler manifold is Riemannian. We show that a proper DWP-manifold is
Landsbergian if and only it is Berwaldian. In continue, we prove that every
relatively isotropic Landsberg DWP-manifold is a Landsberg manifold. We show
that a relatively isotropic mean Landsberg warped product manifold is a weakly
Landsberg manifold. Finally, we show that there is no any locally dually flat
proper DWP-Finsler manifold.
