An electric mower of the battery-operated type has at least one cutting blade, an electric motor for driving the cutting blade, and an electronic piloting unit for the electric motor. At least one optical sensor is deposited upstream of the cutting blade. The optical sensor is configured to deliver； as the mower advances, at least one predictive signal of a quantity of plants to be cut. The electronic piloting unit is configured to establish an optimum rotation speed of the drive motor of the cutting blade, of said predictive signal of the optical sensor, and of a speed of advance of the mower. The method and apparatus are applicable at least to walk-behind mowers.
