In order to improve current potato late blight risk assessment, potato volunteer distribution and densities have been studied in different agricultural environments. Preliminary mathematical approach helped designing sample size for field collecting data; the quadrat method was adopted with variable sample sizes. Large set of data have been collected in two contrasting potato producing regions. Only volunteer densities as influenced by cropping practices (waste piles or volunteers as weeds) and climatic conditions are presented in this report. High densities are found on waste piles whereas volunteer as weeds are dispersed in decreasing densities according the ability of the crop to cover the soil: important density in artichokes, moderate in cereals (wheat, barley) and low in ray-grass. Further implementation of the observed data will help simulate primary inoculum production and optimize predictive quality of current decision support systems, given the fact that any potato volunteer occurrence, even in its lowest expression, is a key factor to the setting of late blight epidemics in the vicinity of a growing potato crop.