FUNGOUS DISEASES IN SHIPMENTS OF SUGAR CANE. 5 



formed i:)n the dry sugar cane at the nodes or in sunken areas on the 

 internodes. 



There has been considerable doubt among investigators as to the 

 manner in which the disease is distributed. Some attribute its 

 spread entirely to the agency of cane borere. Dr. Edgerton states 

 that in Louisiana the infection takes place chiefly through the agency 

 of the moth borer (Diatraea saccharaUs) . In an examination of 55 

 borer cases, he found that 25 were infected with red-rot, 25 not 

 diseased, and 5 doubtful., 



Mr. Butler concludes from his observations that the disease is 

 carried in the sets themselves. He found that the yellow Bourbon 

 cane which came from infected districts gave diseased shoots, while 

 the same variety obtained from disease-free regions and grown 

 adjacent to the former plants produced healthy shoots. It would 

 seem from this experiment that the use of diseased stalks for cuttings 

 is the chief source of infection, although cane borers undoubtedly 

 spread the disease to some extent in those fields already infested with 

 spores from the previous season's growth. 



While the disease may be detected in many cases by inspection, 

 an absolute guaranty of disease-free cane could not be given. ^Ir. 

 Butler also says that — 



Unfortunately, even with the greatest care it is not possible to eliminate diseased 

 sets entirely, for I have obtained cultures of the fungus from sets passed by a particu- 

 larly careful man, and the reddening does not always show at the cut ends. 



And in speaking of the red discoloration of the tissue, which is 

 considered the chief diagnostic character, he states that — 



There is no peculiarity in this discoloration that I have been able to find which 

 serves to distinguish it in all cases from the reddening due to other causes. 



Control. — Selection of resistant varieties -and selection of "seed" 

 are recommended for controlling the red-rot. 



ILIAU. 



Iliau {Gnomonia iliau Lyon) is a disease apparenth^ peculiar to 

 Hawaii, where it is said to have been kno\v^l since the beginning of 

 the sugar industry. Although the disease has been recognized for 

 many years, it was not until 1912 that the entire life history of the 

 causal organism was worked out and published.^ 



Dr. Lyon considers that far greater losses to the sugar planters in 

 Hawaii have occurred from this disease than that caused by all other 

 fungoid diseases combined. The following instances of loss are quoted 

 from his bulletin: 



The manager of one plantation estimated that fully one-half of the shoots in a 200- 

 acre field of 4-monlhs-old plant cane had been killed out by iliau. His estimate was 



1 Lyon, H. L. Diau, an endemic cane disease. Report of Work of the Experiment Station, Hawaiian 

 Sugar Planters' Association. Pathological and Physiological Serias, Bulletin 11, 32 p., 10 fig., 1 pi., 1912. 



[Civ. 120] 



