The first step in the growth of Solanacearum phage α, is the combination of phage with the susceptible host. The fraction of the phages remaining free in the mixed . culture with the host bacteria decreases exponentially with time. The adsorption of phage α seems to be the pseudo first order reaction. The adsorption rates change with .wide ranges under physiological condition of Bact. solanacearum Smith strain S?the host strain of .phage α. The adsorption rate under optimum temperature of host bacteria is much larger than others, and most of phage particles are adsorbed on hosts within about 10 minutes.