DISEASES OF SUGAR CANE 297 



Root Disease : Acute Type. 



Instances have on several distinct occasions come under the 

 observation of the writer in young plant canes in Barbados, and 

 recently m fields of first ratoons in Trinidad, in which plants 

 growing in good well-tHled soH and previously healthy and 

 vigorous have rapidly failed, and have been found to be heavily 

 infested with Marasmius, not only on the roots and leaf-sheaths, 

 but in the tissues of the basal joints of the cane. In such cases 

 the fructifications of the fungus have been produced with un- 

 usual readiness and in considerable quantity. 



The attacks on plant canes have occurred in somewhat 

 scattered stools during the dry season. On one occasion numbers 

 of stools of Ba. 6032 were quite killed out in this way, while 

 plants of B 6450, in the same field, which were not nearly so 

 forward, were unaffected. The basal joints, and the sprouting 

 buds in all stages were internally reddened and filled with Maras- 

 mius mycelium. This type of disease agrees with the effects of 

 Marasmius Sacchan as first described by Wakker in Java, where 

 the ordinary West Indian type, presumably owing to the scarcity 

 of ratoons, does not seem to be famihar. In Barbados M. 

 Sacchan was the species met with in the cases described. 



The most striking instance seen in Trinidad was in a field of 

 Hill s Seedlings 6 and 12, unusually well-grown first ratoons in 

 deep and fairly heavy loam, sufficiently drained. Very many of 

 the large canes were badly infested or completely rotted for 

 several joints at the base, the parts above remaining sound until 

 dried up by the cutting off of their supply of water. The young 

 leafy shoots were also dying upwards owing to infestation in their 

 base. The stools were exceedingly loose in the soil, and many 

 were turned out by the weight of their own canes. An un- 

 identified species of Marasmius, with bluish black stalks, was 

 fruiting abundantly from the roots, the root " eyes " on the stem 

 and the young shoots. Other fungi were not conspicuous. 

 _ While no proof can be offered, the cases described, and others 

 sunilar, present the appearance of active parasitism by Marasmius 

 species. The Barbados examples were attributed to the weaken- 

 mg of resistance by drought, and stools not completely killed 

 recovered after rain. The sudden failure of the Trinidad field 

 described could only be attributed to the effect of a second 

 dressing of sulphate of ammonia on a soil already almost depleted 

 of its small supply of lime. 



The Epidemic on the Bourbon Cane 



The Bourbon cane was introduced into the West Indies in the 



i8th century from the island of Otaheite, where it is believed to 



have originated, and up to the years about 1895 was the variety 



m general cultivation in aU the islands. About 1890 the fields in 



