The relationship between accumulated degree-days (DD) and the emergence of males of the European pine shoot moth (Rhyacionia buoliana Den. & Schiff.) was determined using pheromone traps in a population of this species in a Pinus radiata plantation near Esquel City, Chubut province, at the Patagonian Andes region of Argentina. Traps were checked twice a week during three summer seasons from December 1999 to February 2002. On the second sampling season (2000 to 2001), 100 small branches with infected shoots were collected twice a week to estimate male and female emergence curves. Degree-days requirements (above –2.2 °C) for the seasonal flight of the males of this species were estimated. Predicted DD requirements were 252.26 DD for a 40% catch, 288.22 DD for a 50% catch and 434.53 DD for an 80% catch.