"Bassara" is common on Oriental tobaccos, hence its name. The green spots affecting tobaccos of various types have been given a variety of names, which appear to describe different aspects of possibly different problems. The causes of this ancient and at times major "disease" do not seem to be clearly understood yet.In France, before 1992, a few green spots were observed on leaf-harvested dark-air cured tobaccos and on Burley. Since 1993, damage on Burley tobaccos has increased. The estimated loss due to Bassara was in the order of 8.73 million francs in 1996. Surveys among growers on production and post-harvest parameters, and experiments on various cultural practices (planting density, nitrogen fertilisation, irrigation, topping height, harvesting time ...) conducted on Burley tobaccos in the course of the last three years have allowed a better understanding of the causes of appearance of this phenomenon. We have been able to reproduce symptoms on Burley tobaccos grown under very different conditions. The effects of cultural practices will be discussed, but curing conditions (RH and temperature), in particular at the very beginning of curing, appear to have the most influence. Solutions to avoid the appearance of Bassara will be suggested for air-cured tobaccos.