• Heinrich Anton de Bary (1831-1888) was a botanist  who in 1861-63 proved that Phytophthora infestans caused Late Blight.
• In his published work in 1863 entitled "Recherches sur le developpement de quelques champignons parasites", he reported having inoculated spores of P. infestans on healthy potato leaves and observed the penetration of the leaf and the subsequent growth of the mycelium that affected the tissue, the formation of conidia, and the appearance of the characteristic black spots of the potato blight. He also did similar experiments on potato stalks and tubers. He watched conidia in the soil and their infection of the tubers, observing that mycelium could survive the cold winter in the tubers. From all these studies, he concluded that organisms could not be generated spontaneously (5).
• ​Anton de Bary's study of Late Blight, along with previous studies led to the development of plant pathology and to the revolutionary discovery known as, the Germ Theory, which states that germs cause disease in plants.

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• De Bary was also devoted to the study of the life history of fungi. At that time, various fungi were still considered to arise through spontaneous generation. He proved that pathogenic fungi were not the products of cell contents of the affected plants and did not arise from the secretion of the sick cells (5).​

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