10 CIRCULAR NO. 126, BUREAU OF PLANT INDUSTRY. 



prevalent through a failure of the "eyes" to germmate. Dr. Cobb 

 considers the pineapple fungus to cause the decay of more cane 

 cuttings in Hawaii than that produced by any other one cause and 

 has estimated that in diseased fields the loss varies from 1 to 25 per 

 cent of the plantings. Fortunately the disease has not become widely 

 distributed in the United States, having only been reported from a 

 few localities in Louisiana.^ 



The fungus effects an entrance into the cane at the cut ends of the 

 "seed" or at any point along the stalks through wounds of the rind 

 made either by mechanical or insect injury. The disease (fig. 5), 

 marked by pmk or red streaks, progresses rapidly through the central 

 tissues of the cane, eventually kilhng the buds and thus preventing 

 germination. Later, this central diseased tissue turns dark and finally 

 sooty black through the production of macroconidia. This blackened 

 central tissue is what is known as the "pipe" ^ and is one of the chief 

 characteristics of the disease. 



It is in the younger stages of the disease that the pineapple odor 

 may be detected, being more noticeable in some varieties of cane 

 than in others. These two characters, viz, the "pipe" and the pme- 

 apple odor, are the chief marks by which the disease may be detected. 

 The same fungus causes a disease of pineapples. 



Control. — Destruction of diseased cane and the immersion of the 

 cuttmgs in Bordeaux mixture shortly after the cane is cut are rec- 

 ommended. In the West Indies Howard also recommends that the 

 ends of the cane be dipped in tar as a further preservative. 



SCLEROTItTM DISEASE. 



The Sclerotium. disease (Sclerotium rolfsii Sacc.) is one which at- 

 tacks the leaf sheaths principally, being usually confined to the lower 

 sheaths. It was reported from Louisiana m 1908 and has smce been 

 found in Georgia. The amount of damage caused is somewhat 

 questionable, some clauning that it is confined to the sheaths and does 

 very little harm, while others assert that the fungus penetrates mto 

 the stalk for some little distance and also mto the bud, preventing 

 its germination when used m plantings. This disease is probably 

 the same as that described by Kriiger ^ under the name of red-rot 

 of the leaf sheath and stem and attributed by hmi to Sclerotium sp. 

 He states that the disease is characterized by a brick-red discoloration 



1 Edgerton, C. W. Some sufjar-cane diseases. Louisiana Apriiultural Experiment Station, Bulletin 

 120, 28p.,12fig., iniO. 



2 Cobb, N. A. Fungus maladies of the sugar-cane. Report of Work of t he Experiment Stat ion, Hawaiian 

 Sugar Planters' Association. Division of Tathology and Physiology. Bullet in 5, 254 p., 101 fig., 7 pi., 1906. 



3 Kruger, Wilhelm. Das Zuckerrohr und Seine Kultur. Magdeburg and Wien, p. 459-464, pi. 14, fig. 2-3, 

 1899. 



[Cir. 120] 



