by rind disease. "I have seen fields of this kind in which nearly 

 every laJa showed the spores of rind disease issuing from the sheaths 

 of its lowest leaves, and when the higher leaves were pulled away 

 it was evident that these, too, were attacked and in the first stages 

 of the disease." 



PARASITISM OF THE FUNGUS. 



The fact that Melanconium sacchari has attracted such widespread 

 notice would lead one to assume that it was without question a para- 

 site. Still careful workers cannot accept the prevalence alone of an 

 organism to indicate its parasitism. Though it may not in this case 

 be an active parasite it is necessary at least to know its degree of 

 parasitism before recommending methods of treatment. 



A misleading idea given in many articles on fungous diseases is 

 that the very presence of an organism to the apparent exclusion of 

 others, or the preponderance of one organism over another indicates 

 that it is the cause of whatever disease may be in the host plant. 

 Thus the presence of Melanconium has been assumed by many to 

 indicate that it was the cause of the diseased condition of whatever 

 cane it might be found in. 



jMassee (27) was the first to publish the results of inoculation 

 experiments with this fungus. His experiments were as follows: 



Experitnent I. — A sugar cane, 6 feet high and II/2 inch in diameter 

 at the base, was inoculated by placing Melanconium conidia' upon 

 the base of an old leaf sheath, the leaf having fallen away. After 

 twenty days the ]\Ielanconium fruit was fully developed, the long 

 black filaments of conidia oozing out through minute cracks in the 

 cuticle about half an inch above the node, and from the point of 

 inoculation. At the same time as this experiment was made a small 

 portion of diseased cane containing hyphae of the Melanconium stage 

 was introduced into a slit made in the cane; this experiment re- 

 sulted in the appearance of mature fruit bursting out from the cane 

 after twenty-two days. The cane was cut down ten days after the 

 last-mentioned experiment, and on being split open it was found 

 that at the point where the inoculation was performed by wounding 

 the cane the mycelium had produced the large macroconidia in the 

 decaying tissue. 



Experiment II. — ^^IMelanconium conidia were placed on moistened 

 patches of young living leaves of sugar cane, some of the patches 

 being first carefully washed to remove the bloom on the surface of 

 the leaf, others not being so treated. After twelve days there were 

 no signs of infection on the unbroken surfaces of young leaves and 



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