4 



CIKCULAK NO. 126, BUKEAU OF PLANT INDUSTRY. 



Indies. More recently (1908) it was discovered by Dr. C. W. Edger- 

 ton * at Audubon Park, New Orleans. It has also been reported 

 from Florida and Georgia. 



It is difficult to estimate the amount of damage caused by red- 

 rot, since this does not consist of a loss in stand alone; but, as shown 

 in experiments conducted by Mr. Butler - in Bengal, the most serious 

 loss consists of a decrease in sucrose content with an increase of glu- 

 cose brought about through the ac- 

 tion of the parasite. 



The ])r(^sence of the disease in 

 the field usually does not become 

 evident until the cane is approach- 

 ing maturity. A slight drooping 

 of the upper leaves then becomes 

 noticeable. The leaves wither at 

 the tip, advancing along the margin 

 of the leaf, leaving a green center. 

 Finally the whole crown droops, al- 

 though the stalk remains apparently 

 healthy. According to Butler the 

 diseased ]>lants have the same ap- 

 pearance as those affected by 

 drought, except that green and 

 withered stalks may be seen arising 

 from the same stool. In a bad at- 

 tack these withered stalks become 

 light in weight, fall over, and con- 

 tain practically no juice. 



If a stalk is s])Iit open at the 

 base durmg the early stages of the 

 disease, the fibro vascular bundles 

 may be seen as reddened streaks, 

 which gradually increase in diam- 

 eter, spreading outward into the 

 neighboring tissue. Later, white 

 blotches consistmg of dead cells 

 filled with air may be found in this reddened area. (See fig. 1.) 

 The disease advances upward toward the tip, the tissue finally 

 becoming dark to blackish m color. If the stool is examined it 

 will be found that the discoloration of the stalk extends downward 

 into the cutting and may be traced from here into other stalks which 

 outwardly seem perfectly normal. The fungous spores are usually 



I Edgerton, C. W. Tho red-rot. of sugar cane, Louisiana Agricultural Experiment Station, Bulletin 133, 

 22p.,4pl.,1911. 



■ Butlor, E. J. Fungous diseases of sugar cane in Bengal. Memoirs, Department of Agriculture, India, 

 Botanical Series, v. 1, no. 3, ryi p., U pi., 1906. 

 [Cir. 126] 



Fig. 1.— Red-rot of sugar cane, showing white 

 spots (x) in center of red blotches. (After 

 Lewton-Brain.) 



