Mango hopper population dynamics at different phenological stages was predicted using the growing degree days (GDD) of mango during 2013, 2014 and 2015 under Lucknow climatic conditions.Results revealed that at the time of flowering,there was wide variations in hopper infestation level during three consecutive seasons. Identical trend was observed at early flowering (30 per cent of panicle flowers open), full flowering (more than 50per cent of panicle flowers open), full flowering (all petals fallen or dry) and from fruit set to physiological fruit maturity. The relationship between the GDD and hopper population was established by linear regression analysis and it was inferred that the GDD had explained variation in hopper population upto 66 per cent across the three seasons. Thus, growing degree days served as a basis for predicting hopper population at different phenological stages of mango.