54 A PL.\NT-DISEASE SURVEY IN TEXAS. 



Kernel smut {S phacelotheca sorghi (Lk.) Clint.)- — The smut was 

 present in tlie majority of fields examined. 



Specimens collected : New Braunfels, 1700 ; Llano, 1750 ; San Antonio, 1795 ; 

 Uvalde. 1925 ; Sabinal, 1978 ; Hondo, 1991 ; Bastrop, 2052 ; Luling, 2249 ; Seguin, 

 2294; Victoria, 2500; Gonzales, 2702. 



Leaf -blight {Helminthosporlum turcicwni Pass.). — Very large 

 irregular areas frequently appear on the leaves. They are usually 

 brown with a narrow border of reddish purple. Quite commonly 

 they have a tendency to be formed on the leaf margin or to advance 

 from the leaf tip, so that large portions become involved. Isolated 

 central spots may be found. An Alternaria was very commonly 

 associated with this fungus. 



Specimens collected: Sabinal, 1971; Luling, 2237; Falfurrias, 2493; Stockdale, 

 2638. 



Leaf -spot {C olletotvichiim lineola Cda.). — This disease is character- 

 ized by the formation of numerous oval spots, 1 to 5 mm. in length, 

 with pink center and reddish-purple border, which becomes red on 

 the outer border. The pink centers show the black acervuli in groups, 

 or even a single acervulus, but in many cases acervuli may be entirely 

 absent. The spots may become very abundant and confluent and 

 kill the leaf generally from the tip back. The dead portion turns 

 brown and the affected spots show as darker areas. (PI. XI, fig. 2.) 

 The disease was very abundant and severe in some localities. 



Acervuli black, amphigenous; setse 75 to 150 by 4.5 to 6 /it, base 

 enlarged, very dark throughout, many septate, pointed and generally 

 showing a marked constriction at some point above the base; basidia 

 short, 15 to 20 by 3 to 6 /x, hyaline (PI. VI, fig. 13) ; spores falcate, 

 hyaline, granular or guttulate, and 20 to 30 by 4 to 6 /* (PI. VI, 

 fig. 14). 



Our specimens are doubtfully referred to C. lineola. They are 

 similar to many of the specimens which American mycologists have 

 assigned to this species. It seems, however, that C. lineola Cda. and 

 C. androjyogoim Zimm. have not been clearly differentiated. (See 

 footnote under " Johnson grass," p. 52.) 



Specimens collected : Skidmore. 2806 ; Victoria, 2349 ; Nursery, 25G4 ; Kerrville, 

 1586 ; Beeville, 1865 ; Gonzales, 2703 ; Yoakum, 2754. 



DISEASES OF FIBER PLANTS. 

 COTTON. 



Angular leaf -spot {Bacterium malvaceanim Erw. Sm.). — The angu- 

 lar leaf- spot of cotton {Gossypium herhaceum L.) was observed in the 

 great majority of fields examined. Pellucid spots were observed on 



220 



