 The micro climate resulting from dense canopies, induced by high N fertilization, may have constituted a major climatic parameter in disease epidemiology and successful infection (within sunflower plants).A 2010 study attempted to identify the most crucial agronomic elements of the sunflower premature ripening disease induced by "P. macdonaldii" in south-western France.The combination of high nitrogen fertilization and heavy rain conditions resulted in high disease pressure every year.