Alfalfa weevil embryo and larval establishment mortalities were assessed as a function of embryonic age (aged 10, 25, 50, 75, and 100 degree-days Celsius) when development was interrupted, duration of the interruption (up to 60 days), and temperature at which development was interrupted (4, − 6, − 16°C). Based on the sequence of treatment combinations that significantly influenced mortality, it was concluded that the more advanced the embryonic age when development was interrupted, the longer the interruption, and the lower the temperature during the interruption, the greater the embryo mortality (EM), larval establishment mortality (LEM), and therefore the total mortality (TM) (TM = EM + LEM).