. Diseases of economic plants. Plant diseases. Trees and Timber 401 persist for many years. One stage of this rust occui's ui)on the oalvs. Rust {Coleosporiavi soUdagiiiis (Schw.) Thihii., Perider- mium). — Another species of Peridermiuni occurs upon leaves, producing small, sac-like, tubular outgrowths which contain the spores. This is a stage of a rust which appears later in the season upon golden-rods and asters. Red-rot {Fonies pinicola Cke.).— Upon dead trees this rot begins just under the bark, usually near the tree top, often following bluing. The wood is at first wet and soggy, but soo
. Diseases of economic plants. Plant diseases. Trees and Timber 401 persist for many years. One stage of this rust occui's ui)on the oalvs. Rust {Coleosporiavi soUdagiiiis (Schw.) Thihii., Perider- mium). — Another species of Peridermiuni occurs upon leaves, producing small, sac-like, tubular outgrowths which contain the spores. This is a stage of a rust which appears later in the season upon golden-rods and asters. Red-rot {Fonies pinicola Cke.).— Upon dead trees this rot begins just under the bark, usually near the tree top, often following bluing. The wood is at first wet and soggy, but soon becomes brittle, so that it crumbles readily. The cracks become filled with felted fungous threads. The sporo- phores first appear as fleshy knots, soon red, which widen to pore-bearing shelves. POPLAR, COTTONWOOD Rust (Melampsora sps.). — This is similar to willow rust. See p. 405. European-canker "*-- (Dothichiza pop- ulea S. & B.). — Species of poplar and Cottonwood in nine states show this disease. Death of the cambium re- sults, and following this numerous can- kers and dead branches render the trees unsightly. The disease was probably recently imported on the Lombardy poplar from Europe. New stock should be carefully inspected. Infected wood should be cut out and burned. Canker'"^^ (Cytospora chnjsosperma (Pers.) Fr.). — This serious canker is prevalent in the southwestern United States. Fig. 213. — Pine needle, bearing clus- ter-cup of rust, en- larged. After Clin- Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Stevens, Frank Lincoln, 1871-1934; Hall, John Galentine, 1870-. New York, Macmillan
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