2015-11-242015-11-241925-06June 1925http://hdl.handle.net/10388/7001This disease appears to be relatively new to science although it is probable that it has existed, without recognition, for a considerable length of time. At first, attention was drawn to only the leaf spotting phase of the disease, when Pammel (19) in 1909 first referred to it. In 1910, Pammel and his co-workers (20) described the causal fungus, naming it Helminthosporium sativum. Bolley (5), however, was the first to point out that fungi such as this were present in soil, and tended to accumulate in wheat-sick soils following a period of intensive cropping. This observation was confirmed by Beckwith (4). Stakman (23) found that li. sativum attacked not only the leaves but also the stems and roots of barley and rye, causing a seedling blight and a root rot. She found the fungus would attack the leaves of certain grasses as well. The studies of Christensen (6) showed that li. sativum had a much wider host range than that formerly recognized and there were marked differences in varietal susceptibility to attack. Henry (13) found that li. sativum commonly occurred in discolored seed of wheat.Thesis