LIST OF DISEASES OF ECONOMIC PLANTS 81 



POPULTJS— Continued. 

 Populus spp., poplar, cottonwood, aspen — Continued. 



M. rhabdospora (Ell. and Ev.) Magn., leaf-spot. N. J., Wis. 



Melampsora abietis-canadensis (Farl.) F. Ludwig, rust. General. 



M. albertensis Arth., rust. Western States. 



M. larici-populina Kleb., rust. General. 



M. medusae Thuem., rust. General. 



M. occidentalis Jack., rust. Western States; Wis. 



Napicladium tremulae (Frank) Sacc, twig-blight. Minn. 



Ozonium omnivorum Shear (Phymatotrichum omnivorum (Shear) Dug.), 



root-rot. Tex. 

 Phoradendron flavescens (Pursh) Nutt., mistletoe. Southwest. 

 P. flavescens macrophyllum Engelm., mistletoe. N. Mex., Ariz. 

 Phyllosticta alcides Sacc, leaf -spot. Ohio, Idaho. 

 P. brunnea Dearn. and Barth., leaf-spot. Mont., Colo., Ariz. 

 P. intermixta Seaver, leaf-spot. Kans. 

 P. maculans Ell. and Ev., leaf -spot. N. Y., Kans. 

 Polyporus dryadeus (Pers.) Fr., white root-rot. 



P. dryophilus Berk., white pocket heartwood rot. Me., N. H., Wis., Colo. 

 Rhytisma nervate (Alb. and Schw.) Rehm, tar-spot. N. Y. 

 Sclerotium bifrons Ell. and Ev., leaf-spot. New England and Adirondack 



region; Wis., Wyo., Colo., Utah, Oreg. 

 Septoria musiva Pk., leaf -spot. Widespread. 

 S. populicola Pk., leaf-spot. Nebr., Tex. 

 Stereum purpureum Fr., silver-leaf. Wash. 

 Taphrina aurea (Pers.) Fr., yellow leaf blister. Me., Mass., N. Y., N. J., 



Iowa; Pacific coast. 

 Trochila popularum Desm., leaf -spot. Widespread. 

 Uncinula salicis (DC.) Wint., powdery mildew. General. 

 Venturia tremulae Aderh., scab. Me., Wash. 



PRIMULA. 



Primula sp., primrose. 



Botrytis cinerea Auct., gray-mold. Conn., S. C, Ohio. 

 Heterodera radicicola (Greef) Muell., root-knot. Conn., W. Va. 

 Ramularia primulae Thuem., leaf-spot. Conn., N. Y., Del. 

 Mosaic, undet. Pa. (greenhouse). 



PROSOPIS. 



Prosopis sp., prairie mesquite. 



Cercospora prosopidis Heald and Wolf, leaf-blight. Tex. 



Erysiphe sp., powdery mildew. Tex. 



Gloeosporium leguminum Cke., pod-spot, anthracnose. Tex. 



Neoravenelia holwayi (Diet.) Long, rust. Tex., Calif. 



Phoradendron californicum Nutt., mistletoe. Tex., Ariz., Calif. 



P. flavescens (Pursh) Nutt., mistletoe. Tex. 



P. flavescens macrophyllum Engelm., mistletoe. Ariz., N. Mex. 



Phyllosticta juliflora Ell. and Barth., leaf -spot. Tex. 



Ravenelia arizonica Ell. and Ev., rust. Tex., Ariz., Calif. 



PRUNUS. 



Prunus sp., cherries (sweet and sour). 



Armillaria mellea (Vahl) Quel., root-rot. Ohio, Mich., Ark., Pacific coast. 

 Bacillus amy iov or us (Burr.) Trev. (Erwinia amylovora (Burr.) Com. S. A. B.), 



blight. Ohio, Mich., Kans., N. Mex., Wash. 

 Bacterium cerasi F. L. Griffin, bacterial gummosis. Okla., Ind., Mich., 



Idaho; Pacific coast. 

 B. pruni EFS. (Phytomonas pruni (EFS.) Com. S. A. B.), bacterial spot. 



N. Y., Ala., Okla., 111. 



B. tumefaciens EFS. and Town. (Phytomonas tumefaciens (EFS. and Town.) 

 Com. S. A. B.), crown-gall. Mass., N. Y., Okla., Ohio, N. Mex., Colo.; 

 Pacific Northwest. 



Cercospora cerasella Sacc, leaf -spot. Ga., Fla., Ala., Miss. 



C. circumscissa Sacc, shot-hole. Widespread. 

 C. rosicola Pass., leaf -spot. Oreg. 



