Degree-day models for cabbage maggot are used to predict emergence for each generation when risk of damage in highest. These maps use a simple degree-day calculation of lower (43°F) a threshold with an April 1 biofix date (Eckenrode and Chapman 1972. Ann. Entomol. Soc. Am. 65: 151-156). Average daily temperatures that fall below the lower threshold are set to 43°F.