Why do you suppose we use Koch's postulates instead of something called De Barry's?

Answer 1

Anton deBary, a German botanist, performed the experiments that proved the role of the fungus in the blight. He subjected potato plants to the cool, wet environmental conditions that favored blight. To some plants he applied sporangia from blighted plants, but others he kept as "control" plants and applied no fungus. Even though both sets of plants were exposed to the same favorable environment, only the plants inoculated with the fungus became blighted. It was clear that the plants did not rot away because they absorbed too much water. In the absence of the pathogen, no disease occurred.