84 A PLANT-DISEASE SURVEY IN TEXAS. 



CASTOR BEAN. 



White leaf -spot {Cercospoi^a ricinella Sacc. and BerL). — On the 

 foliage of the castor bean {Ricinus coirmiunis L.) this fungus causes 

 the formation of small circular spots from 1 to 2 mm. in diameter. 

 These spots are gray on both surfaces and have a well-defined, raised, 

 purple margin. When the spots are abundant the leaves become 

 yellow. 



Specimens collected: Falfurrias, 2443; Flatonia, 2737; Hallettsville, 2780; 

 Austin, 2921. 



CENTURY PLANT. 



Blight {Stagonospora gigantea Heald and Wolf, 32). — The disease 

 begins on the tips or margin of the leaves of the century plant 

 {Agave americana L.) and advances toward the base. (PL XVI, fig. 

 1.) The diseased tissue becomes dry, gray, and zonate, marking the 

 periodic growth of the fungus. The pycnidia are on both leaf sur- 

 faces, covered at first, and at length protiTiding. They vary from 

 500 to 600 (I in diameter. (PL XVI, fig. 2.) The spores are large, 

 hyaline, cylindrical, and slightly clavate, densely granular and fre- 

 quently with many guttulse, three septate and 72 to 115 by 13 to 15 ji. 

 (PL V, fig. 3.) Our species differs from S. macrospora (Dur. and 

 Mont.) Sacc, principally in having much larger spores, and also 

 larger pycnidia. 



This disease was veiy serious, blighting the plants in all the locali- 

 ties where it was observed. 



Specimens collected: Austin, 1283 (type specimen); San Antonio, 1377; 

 Boerne, 1648. 



CHINA ASTER. 



Stem-rot {Fusanum sp. ?). — This fungus on the China aster {Cal- 

 listeinma chinensis (L.) Skeels) was the cause of a very considerable 

 loss in the one locality in which it was observed. The young plants 

 in the benches remain without any apparent growth for a time, then 

 wither and die, with a serious disintegration of the stem near the 

 ground. 



Specimen collected : Austin, 1445. 



CHRYSANTHEMUM. 



Leaf-spot {Septoria chrysanthemi Allesch.). — This leaf-spot of 

 chrj^santhemum {Chrysanthemum stipidaceum (Moench) AV. F. 

 Wight) has been collected twice from greenhouses. In some cases 

 it causes a considerable amount of defoliation, especially on the lower 

 part of the plant. 



Specimens collected: Austin, 380; Georgetown, 2368. 

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