This study investigates the characteristic behavior of disturbances on the interface of a needle crystal, Ivantsove parabola, based on an asymptotic analysis as well as a numerical study. Focusing on tip growth and width behavior, we examine anisotropy in surface energy, initial strength of the disturbances. It is found that the characteristics of a tip growth depends on the distance away from dendrite tip. The constant wave-length, ?o, suggests that the possiblity of the existence of an attractor in ?o. An evolution of finger competition between two disturbances with different initial strengths is investigated to understand the selection mechanism.