56 A PK^ISTT-DISEASE SURVEY IN TEXAS. 



Seguiu, 2295; Georgetown, 2388; Victoria, 2342; Cuero. 2583: Stoclidale, 2646; 

 Gonzales, 2683; Flatonia, 2727; Yoalium, 2760; Hallettsville, 2798; Falfurrias, 

 2450. 2466 ; Alice, 2497 : Skidmore, 2499. 



Root-rot. — This is a new disease, which is characterized b}' the 

 dying of the affected plants, the dead plants exhibiting much the 

 same general appearance as in the case of the well-known Texas 

 root-rot. The patches maj^ be small or they may reach nearlj'' an acre 

 in extent. A few plants may persist within the affected areas. At 

 the circumference of the arear of dead plants may be found living 

 plants which are affected with the disease, but have not yet suc- 

 cumbed. These diseased plants show frequently a slight chlorosis 

 of the foliage and a diseased condition of the root ; others that are 

 affected will show about normal foliage, arid the only indication of 

 the presence of the disea-se is the abnormal condition of the root. 

 Many of these affected plants may wilt down and die in the course of 

 a few hours. 



The roots of diseased plants show a marked constriction at the 

 croAvn, and the root remains apparently smaller from that point 

 downward. An examination of the surface shows many delicate 

 brown hyphse aggregated in strands or making looselj" interwoven 

 masses; numerous small wartlike pustules also appear on the main 

 root as well as on the branches. These wartlike nodules are sclerotal 

 aggregates of fungous tissue which are slightlv protruding from the 

 cortex (PI. XI, fig. 3). 



The mycelium shows some Rhizoctonia characters, and fruits were 

 found in the field in two cases, which may be connected with the 

 fungus present. The systematic position of the fungus has not j'^et 

 l)een determined, but cultural work is in progress which should throw 

 light upon its relationship. The cultures up to the present time 

 have failed to produce spores upon any media, but cultural characters 

 show that the fungus is not a Rhizoctonia. 



Specimens collected; Falfurrias, 2433, 2434, 2466. 



Rust {Aecidium gossypii Ell. and Ev.). — The spots produced by 

 this fungus show on the upper surface of the leaf as circular or 

 subcircular areas, 3 to 5 mm. in diameter, with reddish-purple or 

 dark-brown centers, slightly depressed and surrounded by a narrow 

 zone of yellow or orange. The under surface of the spot is slightly 

 hypertrophied and contains numerous cluster cups, 150 to 260 /a in 

 diameter, which have a bright yellow or orange color. From one to 

 three or four spots occurred on a single leaf. While the fimgus was 

 general throughout the fields where it was observed, it was not 

 abundant, and caused but little injury. This fungus was first re- 

 ported from California (22) and no records of its occurrence in other 

 parts of the United States have been found. 



Specimens collected : Falfurrias, 2435, 2452. 



226 



