We present proof-of-concept measurements of the vortex line density generated by a quartz tuning fork resonator probed by the attenuation of second sound in superfluid 4He at 1.6 K. The force–velocity response of a quartz tuning fork operating at a frequency of 31 kHz exhibited the onset of extra damping at a velocity of 0.5 ms−1. Attenuation of the 5th resonant mode of second sound was observed at the same velocity, indicating the production of vortex lines. Our measurements demonstrate that an increase of the drag coefficient corresponds to the development of quantum turbulence.