The potato tuberworm,Phthorimaea operculella(Zeller) population size increased as the crop season progressed and was at its annual highest during the summer planting. A significant positive correlation was established between pheromone catches of adult moths, foliar larval populations and the plant infestation by potato tuberworm in all the six cropping seasons. Pheromone trap data could be used to predict foliar population and damage.