DISEASES AND PESTS 53 



authority on bacterial diseases of plants, made a personal 

 visit to the infected districts in Cuba ; and other visits 

 were subsequently made under his direction. 



The Estacion Central Agronomica de Cuba began the 

 investigation of the disease in 1904. The results of this 

 study were published by Horne. John R. Johnston has 

 since published a monograph on the subject. The 

 disease is certainly known from Havana to Artemisa, at 

 Cardenas, Cienfuegos, Manzanillo, Banes, on the coast 

 west of Santiago de Cuba, and practically throughout 

 the Baracoa district. A plantation cannot be established 

 in any part of the island, with any reason to feel safe 

 from the appearance of the disease, before the trees are 

 mature. Horne believes this to be true of all the 

 neighbouring areas, although the disease is unknown 

 and apparently not present in Puerto Eico. 



The description of the disease is taken from Horne : 



In a bearing tree the first symptom noted is usually that 

 the young nuts drop. The half-grown nuts usually fall a little 

 later, but often a few ripe nuts hang on the tree until it is 

 completely dead. After the dropping of the first small nuts 

 the flowers will be seen to be blackened and, as the disease 

 advances, the flowers and racemes will be blackened when the 

 sheath bursts and allows them to protrude. 



As the disease advances still further, younger swords 

 (tetas) are affected and their development is stopped. When 

 these affected swords are examined, on the surface of the outer 

 sheath there is a rot which evidently is progressing downwards. 

 In the case of the youngest ones this may penetrate into the 

 cabbage of the trunk, but those nearly ready to burst before 

 being affected have never been found with the rot following 

 down to the trunk. Evidently the tissue of the lower part of 

 the stalk of the opened flower cluster is too hard. Infection of 

 the inner sheath always follows that of the outer, and that of 

 the rachis is still later. Single flower buds are found blackened 

 inside the still unopened sheaths, where apparently there is 

 no chance for the entrance of insects or the introduction of 

 infection. 



During these studies no case has been found in which 

 the disease had attacked and destroyed part of the flower 

 clusters and finished its course, leaving the rest of the tree 

 healthy, although in the very severely attacked groves at 



