Recent SU(3) gauge field lattice data for the equation of state are in
terpreted by a quasiparticle model with effective thermal gluon masses
. The model is motivated by lowest-order perturbative QCD and describe
s very well the data. The proposed quasiparticle approach can be appli
ed to study color excitations in the nonperturbative regime. As an exa
mple we estimate the temperature dependence of the Debye screening mas
s and find that it declines sharply when approaching the confinement t
emperature from above, while the thermal mass continuously rises.