A highly significant negative linear correlation (r=– 0·911, P=0·001) was observed between Xyleborus fornicatus Eichh. population levels in tea plants and the crop size in the preceding month. A highly significant negative linear correlation (r=– 0·858, P=0·001) was also observed between Xyleborus population levels and the percentage of healed galleries of the respective samples. Cambial activity, which has a direct relationship with crop size, determines the rate of healing of brood galleries, and this seems to be the critical factor that regulates population size within a pruning cycle. Since the population has an inverse relationship to crop size and as the latter could be predicted in advance using weather parameters, it should be possible to predict population levels of Xyleborus in advance.