[en] By an electromagnetic incompressible two fluid model describing both ion temperature gradient drift modes (η_i modes) and resistive interchange modes (g modes), a new type of η_i mode is studied in cylindrical geometry including magnetic shear and an averaged curvature of Heliotron/Torsatron. This η_i mode is destabilized by the coupling to the unstable g mode. Finite plasma pressure beta increases the growth rate of this mode and the radial mode width also increases with plasma pressure beta indicating large anomalous transport in the Heliotron/Torsatron configuration. The transport from η_i mode exceeds that from resistive g when the mean-free-path exceeds the machine circumference. For plasma beta above two to three times the Suydam limit the m = 1/n = 1 growth rate increases from the η_i mode value to the MHD value. 13 refs., 5 figs