planted without the removal of the diseased sheaths aiid two hundred 

 were planted after stripping. The germination was as follows, count- 

 ing shoots per hundred seed, the planting being made March 27 : 



This apparently showed that better germination followed non- 

 removal and that red spot did no injury. In the mature cane of 

 this planting there was no difference in the respective amounts of 

 the disease present. 



In the experiment of 1913, three hundred seed with the leaf- 

 sheaths on and three hundred with them removed Avere planted in 

 alternate rows of one hundred and lift}^ seed each. At the end of 

 the counts of the germination, the two rows planted with the sheath 

 on gave seven hundred and eight shoots, the other two rows one thou- 

 sand and three, a result exactly opposite to that obtained the first 

 year. In the latter experiment the leaf sheaths may have presented 

 a mechanical obstruction to germination. The use of a different 

 variety (Otaheite) may also explain the difference in part. Subse- 

 quent growth showed no observable difference in the amount of disease 

 present on the two lots. 



There is a very marked varietal resistance to the fungus. Cris- 

 tallina and B-1753 are usually badly affected, Otaheite somewhat less 

 and yellow Caledonia, D-116, and the red or purple canes such as 

 cavengerie, etc., are seldom much infected. It can not be determined 

 that the amount of infection sho^^■s any definite relation to the so-called 

 hardiness of the variety. No environmental conditions have been 

 noted which appeared to have any connection with the amount of 

 disease present. 



Cercospora vaginae Kriiger. 



Hyphae dark, cobwebby, arising from the center of a red discolo- 

 ration on the leaf-sheath ; sporophores more or less erect, rigid or 

 flexuous at the tip; spores solitary usually at the tip, occasionally 

 borne on the side of the sporophore, one to several celled, 4^8 

 mu. X 15-40 mu. 



Porto Rico. — On cane leaf -sheaths, Rio Piedras, March, 1912, 

 4293, 4296 ; Los Canos, Dec. 8, 1911, 4118 ; Fajardo, March 25, 1912, 

 4290; Arecibo, March, 1916, 5088. Observed in all parts of the 

 Island, on practically all varieties of cane. fPl. XXIX, fig. 19. 20; 

 pi. XXIV, fig. 1.) 



200 



