The flight activity of six species of the flea beetles of the genus Phyllotreta was monitored by means of yellow water traps in three years. The percentage composition of the total catch of adults made up of the species was 29.5% (P. vittula), 28.8% (P. atra), 17.5% (P. undulata), 12.8% (P. nigripes), 7.1% (P. vittata) and 4.3% (P. nemorum). The flight activity of each species had two peaks. The spring peak was made up of overwintering adults migrating to host plants, and the summer peak of newly emerged adults. A regression model of flight activity in both generations was established based on the sum of day degrees above the temperature threshold for flight (10.2°C). The onset of flight activity of adults of the overwintering generation in spring started at 30 day degrees, and that of the adults of the summer generation at 280 day degrees. These temperature requirements for flight activity indicate when best to inspect crops for effective pest management.