This root disease is confined to the South and Southwest, having been found particularly in Texas and New Mexico. Pears are frequently injured to a very appreciable extent. Affected trees usually show, on the roots, threads of the causal fungus, Ozonium omnivorum; these threads are at first whitish, then dirty-white or brown. Pear - trees in close proximity to affected cotton, which also is affected by this disease, are most liable to infection. It is believed that a tree once diseased cannot be saved. (See under Apple, page 146.)