50 A PLANT-DISEASE SURVEY IN TEXAS. 



DISEASES OF WILD AND CULTIVATED GRASSES. 

 BERMUDA GRASS. 



Leaf -spot {Helminthosjyorium giganteum Heald and Wolf, 32). — 

 This disease on Bermuda grass {CaprioJa dactijlon (L.) Kuntze) 

 is characterized by the presence of numerous j^ellowish or pale straAv- 

 colored spots, 0.5 to 1 mm. wide by 1 to 4 mm. long, longitudinally 

 elongated, and with a narrow brown border. The spots are generally 

 absent from the leaf sheath, and when numerous they may become 

 confluent on the laminae and thus cause somewhat extended dead 

 areas. 



The conidiophores are dark brown, many septate, 9 to 12 by 200 to 

 400 IX, with a slighth' bulbous base (PL VII. fig. 6) ; the spores are 

 elongated, cylindrical, with slightly tapering ends, five septate, pale 

 brown, densely granular contents, 15 to 21 bv 300 to 315 /i. (PI. VII, 

 fig. 7.) 



Specimen collected: Falfuriias. 2440 (type specimen). 



CRAB-GRASS. 



Gray-spot {Piricularia grisea (Cke.) Sacc). — Circular or slightly 

 elongated spots appear on crab-grass {Syntherisma sanguinalis (L.) 

 Dulac). These spots are dirty yellow or grayish in color, 1 to 5 mm. 

 in diameter, with prominent purple borders. Very frequently the 

 areas are confluent so that the entire leaf tip becomes dry. 



Specimen collected : Uvalde, 1936. 



Rust {TJroniyces sp.). — Observed in but a single locality. Affected 

 leaves showed an abundance of sori. 



Specimen collected: Falfurrlas, 2490. 



FEATHER GRASS. 



Balansia blight {Bdlansia hypoxylon (Pk.) Atk.). — This fungus 

 on feather grass {/Stipa leiicotricha Trin.) destroys the entire spike, 

 forming around the vascular tissue of the spikelets a pseudosclero- 

 tium which is grayish or bluish black on the outside, whitish within, 

 and 4 to 15 mm. in length. (PL XI, fig. 1.) The black pulvinate 

 stromata project prominently from this sclerotium. These stromata 

 contain the flask-shaped perithecia. This blight is quite common 

 during the last part of April and the first part of May. "When this 

 species was made the basis of a study by Atkinson (2) the host plant 

 of the Texas material was undetermined. 



Specimen collected: Austin, 3071. 



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