The authors present an investigation into the growth of a radially symmetrical ripple, superimposed on a Gaussian laser beam propagating in a plasma. The growth rate, being a function of plasma and pump parameters, is shown to be drastically influenced by these parameters in collisional as well as collisionless unmagnetized plasmas. In low temperature and intensity regimes, the growth of the ripple plays a relatively more dangerous role in collisional plasmas as compared to collisionless plasmas.