The effect of an electric field on spin precession in In0.5Ga0.5As/GaAs self-assembled quantum dots is calculated using multiband real-space envelope-function theory. The dependence of the Lande g tensor on electric fields should permit high-frequency g tensor modulation resonance, as well as direct, nonresonant electric-field control of the hole spin. Subharmonic resonances have also been found in g tensor modulation resonance of the holes, due to the strong quadratic dependence of components of the hole g tensor on the electric field.