A wind turbine with a rotor mounted on a hub section, wherein the rotor comprises a plurality of blades, at least one of which comprises a main blade section, which is optionally pitchable, and an auxiliary blade section mounted to the hub section. The auxiliary blade section is arranged in the area of a leading edge or of a trailing edge of the main blade, so that each blade is thereby provided with a leading edge slat or a trailing edge flap formed by the auxiliary blade section to increase the planform area of the blade and increase aerodynamic lift. A control method for a wind turbine controls a main blade section and an auxiliary blade section to provide different angles of attack to reduce undesired loads at sudden extreme changes of wind speed, e.g. during idling of the wind turbine. In a separate aspect, the invention provides a wind turbine having a blade with a non-pitchable leading edge slat, which extends at most 40% of the radius of the rotor in a longitudinal direction of the blade.