Editing Heinrich Anton de Bary (section)

====''Puccinia graminis''====
He did a thorough investigation on ''[[Puccinia graminis]]'', the pathogen that produces rust in wheat, rye and other grains. He noticed that ''P. graminis'' produced reddish summer [[spore]]s or "[[urediniospore|urediospores]]", and darker winter spores or "[[teleutospore]]s". He inoculated the leaves of barberry (''[[Berberis vulgaris]]'') with [[sporidia]] from winter spores of wheat rust. The sporidia germinated, leading to the forming of [[aecia]] with yellow spores, the familiar symptoms of infection on the [[barberry]]. De Bary then inoculated [[aecidiospore]]s on moisture-retaining slides and then transferred them to the leaves of seedling of [[rye]] plants. In time, he observed the reddish summer spores appearing in the leaves. Sporidia from winter spores germinated only on barberry. De Bary clearly demonstrated that ''P. graminis'' lived upon different hosts at different stages of its development.  He called this  phenomenon "[[heteroecism]]" in contrast to "[[autoecism]]", in which development takes place only in one host. De Bary’s discovery explained why the practice of eradicating barberry plants was important as a control for rust.<ref name="Robinson"/>