i64 CHAPTER IX 



Top Rot. — This is a condition where the vegetative point oi the cane 

 rots and turns to a black, sUmy, foul-smelling substance. Bacteria are 

 associated with this condition but their presence is believed to follow the 

 disease, and not to cause it. Earle believes that the real agent is the 

 Myxomycete, observed as a cause of root disease by Matz, which, invading 

 the whole cane, so weakens the tissues as to prepare the way for the 

 bacteria associated with the condition. 



"Rind Disease" and Rind Diseases. — By the term "rind disease" one of 

 two things may be meant. Reference may be made specifically to the disease 

 due to the organism, Colletotrichum falcatum, and already described under 

 the heading " Red rot of the stem." It is in this sense that the term is used 

 in the publications of the Imperial Department of Agriculture for the West 

 Indies. Secondly, reference may be made to a condition of dead or dying 

 cane associated with the presence on the rind of black erumpent pustules 

 and hyphse, which may be due to at least three distinct organisms. The 

 whole matter has been very confused, and doubt and diversity of opinion 

 stni exist. The confusion may be best realised by regarding the subject 

 in its historical sequence. 



In 1878 diseased canes with the peculiar characteristics mentioned above 

 were sent to Kew from Porto Rico, at which time there was an outbreak 

 of rind disease in the sense noted secondly above. ^^ The fungus on these 

 canes was described in manuscript by Berkeley as Darluca melasporum. 

 Cooke redescribed this fungus, giving it the name of Strumella sacchari, 

 but stating that the origin of the canes was Australian. Saccardo shortly 

 afterwards changed the name to Coniothyrium melasporum, and quoted 

 the description incorrectly. Later, canes suffering from the "Maladie de 

 la Gomme ' ' were sent from Mauritius by Boname to Prillieux and Delacroix 

 in Paris. ^^ They identified the organism on these canes as Coniothyrium 

 melasporum, attributing the disease to the most prominent characteristic. 

 Another description is due to Ellis and Everhard^^ in Jamaica, who named 

 the organism TruUula sacchari. About i8go, the cane known in the British 

 West Indies as Bourbon became very sick, and this sickness received the name 

 of Rind Disease. It is thus described in the Kew Bulletin : — ^^^ 



" Canes infected with rind fungus are first noticed by dark red or brown 

 patches in one or two joints toward the middle or base of the cane. The red patch, 

 having made its appearance, rapidly spreads upwards and downwards, the 

 infected area darkens in appearance, and is evidently rotten. Little black specks 

 make their appearance between the joints, breaking from the inside to the 

 surface." 



Another feature of the disease was that it only manifested itself in ripe 

 cane shortly before harvest. Targe areas ready for the cutlass would die 

 and dry up in a few weeks, presenting the peculiar lesions. This condition 

 was investigated at Kew by Massee, who ascribed the sickness to the most 

 prominent characteristic, naming the fungus Trichosphceria sacchari .'^^^ 



After the estabhshment of the Imperial Department of Agriculture for 

 the West Indies, the cause of the sickness was examined on the spot by 

 Howard.^°2 jjg found two fimgi on diseased cane, both of which he grew 

 in pure culture. One of these was the Colletotrichum falcatum, associated 

 with the red rot of the stem, and the other was a fungus to which the black 

 erumpent hyphae were due. This was only observed in the melanconium 

 stage, and has since become known as Melanconium sacchari. By means 



