  We theoretically discover that unique eigenmodes of skyrmion crystal (SkX)
are not only magnetically active to ac magnetic field (H^w) but also
electrically active to ac electric field (E^w) in a multiferroic chiral-lattice
magnet Cu2OSeO3, which amplifies the dynamical magnetoelectric coupling between
E^w and the spin texture. The resulting intense interference between their
electric and magnetic activation processes can lead to unprecedentedly large
diode effect on the microwave, i.e., its absorption by SkX changes up to ~20%
when the incident direction is reversed. Our results demonstrate that the
skyrmion can be a promising building block for microwave devices.
