A transport equation for the density operator of the Landau quasiparticle in the presence of a constant magnetic field is derived using the generalized self-consistent field (GSCF) method. An appropriate matrix representation in $\stackrel{\ensuremath{\rightarrow}}{\mathrm{k}}$ space is introduced. The resulting transport equation for the Landau one-quasiparticle density matrix is gauge invariant and not restricted to the long-wavelength limit. In the long-wavelength limit the GSCF transport equation becomes Silin's phenomenological transport equation. The role of exchange and correlation is discussed. It is shown that to a good degree of approximation, the quasiparticle velocity can be replaced by the bare particle velocity, and the Lorentz-type term involving the fluctuation of the self-consistent-field potential can be neglected.