The life history of the agricultural pest Phyllotreta cruciferae (Goeze), including location of overwintering sites, time of spring emergence, reproductive phenology, and seasonal changes in feeding and responsiveness to yellow sticky traps, was studied in the northeastern United States from 2001 to 2003 to provide growers with information to improve their management of flea beetle populations in Brassica crops. Samples of leaf litter, organic debris, and soil were collected from a variety of vegetation types to determine the location of flea beetle overwintering sites surrounding agricultural fields. Significantly more P. cruciferae were found in the leaf litter beneath shrubs and brush or in wooded areas than in grass, within-field debris, or in soil samples taken within each vegetation type. Weekly dissections of field-collected female beetles suggested the occurrence of a partial second generation by P. cruciferae in 2003. In laboratory assays of beetles collected weekly from Brassica fields in Massachusetts, both adult beetle feeding on Brassica foliage and beetle responsiveness to yellow sticky traps shows two peaks (June and August) that corresponded to the first and second generations. Beetle catch on yellow sticky traps was highly correlated (2002: R² = 0.8; 2003: R² = 0.6) with the mean number of feeding holes on injured plants.