30 



to the Garden. Six hundred and thirty herbarium specimens v/ere taten 

 of which nearly five hundred are fungi, the remainder being lichens and 

 mosses with a few fresh water aJgae. These will be studied and lists pre- 

 pared as soon as other duties will permit. The following plant diseases 

 were observed. In a number of cases cultures were secured of the organisms 

 found in the diseased tissues and a more extended account will be prepared 

 when laboratory studies and inoculation experiments with these organisms 

 have been completed. 



Logwood Boot Bot ; Cn some estates, especially toward the western end 

 of the island, logwood trees are dying in considerable numbers. 



The diseased trees usually occur in groups, the infection spreading 

 slowly but in constantly widening circle. An examination of dying trees 

 shows the roots to be badly rotted. 'Jheir surface tissues are invaded by 

 a white fungus mycelium that is usually more abundantly developed in the 

 region between the bark and the wood. The disease seems to first attack 

 the small rootlets gradually spreading to the laiger roots and the crown 

 when the tree dies. In many cases seeming healthy trees near the border 

 of infested areas were found to have the roots on the side next the dying 

 trees badly diseased, while on the other side they were still perfectly 

 healthy. The fungus seems to be the mycelium of some of the Hymen- 

 omycetes. Numerous species of Polyporaceae and Thelephoraceae were 

 taken on logwood stumps and logs, but in no case could their connection 

 •with this root rot be satisfactorily proven. "Whatever the nature of the 

 fungus, leaving sfumps of trees that have died from this disease in the 

 Dcighbourhood of living trees is clearly dangerous. Dying trees should be 

 dug and the roots burned as soon as the disease can be detected. Where 

 it is confined to certain shall definite areas as is often the case, it would 

 be advisable to dig a trench three feet deep just outside of the diseased 

 area in order to prevent its spread underground to the roots of healthy 

 trees. On a few of the estates examined the disease was so widely 

 scattered that this method of treat > eut would not be practicable. Here 

 it would seem best to clear the infested tract entirely of logwood, market- 

 ing such as was sufficiently mature, and allowing the land to grow up in 

 pimento and limes, or reserving it for pasturage or cultivation. It should 

 be mentitned in this connection that pimento trees are said to die from a 

 similar root rot in some parts of the island. If this should prove to be 

 identical with the logwood root rot, pimento would not be available as an- 

 alternative crop. 



This root rot seems to spread slowly. One old logwood chipper assured 

 me that trees had been dying for thirty five years on a spot that he pointed 

 out. This area does not now include over three or four acres. This would 

 indicate that by vigorous measures it could be controlled. The disease 

 was found on various kinds of soils and under moisture conditions varying 

 from dry rocky hill sides to the margin of swamps. In some cases the 

 diseased areas were on spots where the soil was rich and deep and the 

 moisture and drainage condition porfect. It was not observed on the 

 heavy clay lands toward the eastern end of the island but whether this 

 was due to the absence of infection or to the character of the soil could 

 not be determined. 



" Bastard" Logwood : The logwood dye of commerce is extracted from 

 the heart wood of mature trees of Eaematoxylon Campechianum. In Jamaica 

 occasional trees are found in which little or no haematcxylin is found. 

 In its place is a fubstance yielding a dull yellowish green dye. Such 

 sticks are rejected by logwood buyers for they not only yield none of the 

 desired colouring material, but if mixed with the normal wood in any 

 quantity, do harm by spoiling the tint of the extract. Complaints have- 



