184 TEINIDAD AND TOBAGO BULLETIN. [XVIIL 4. 



limited, and that the presence of the stumps of these especially suscep- 

 tible trees in dealings h is 'i good deal to do with the appearance of the 

 disease. It is a well-known fact, already referred to above, that there _ 

 is such a special susceptibility in the case of certain cultivated and 

 semi- cultivated trees. Accurate information as to the identity of 

 the forest trees most concerned is difficult to obtain. By no means 

 all the forest trees have been identified, and to such as have, 

 the patois names which form the connecting link with local knowledge 

 are often loosely appUed. In Dominica a large number of cases 

 certainly occur in connection with deeply buttressed stumps com- 

 monly referred to chataignier, a name usually identified with two 

 or three species of Sloanea. One planter has suggested that the 

 closely similar stumps of bois cote are in his district more com- 

 monly the source of the trouble. Infection from the roots of 

 mahoe cochon {Sterculia caribaea) and chataignier graud-feuille 

 {Sloanea Massoni) in Dominica has been already mentioned. South 

 and Brooks give mahoe piment {Daphnopsis tinifolia) and bois cabrit 

 or goatwood [Algiphila martinicensis) as susceptible trees in St. Lucia. 

 The perithecia of 'B. Pepo were described by Patouillard from locust 

 {Hyjnenaea Courbaril) in Guadeloupe. 



The disease is unknown in the older lime estates, which have no 

 recent clearings. This cannot be regarded as wholly due to the much 

 lower rainfall which most of them receive, since even near the coast 

 lime trees contract the disease when planted as substitutes for diseased 

 cacao. There is moreover at least one forest estate in the same district 

 as some which are badly affected, where the clearings are old enough 

 for the stumps to have disappeared, and where, in the limes which have 

 replaced the crops first planted, root disease has given no trouble. In 

 comparing this position with that of cacao cultivations, in which the 

 disease due to B. Pepo is very liable to appear after they have been long 

 established, it has to be remembered that the canopy is not so dense in 

 a lime field, and that shade trees are not grown. 



b. IN CACAO CULTIVATIONS. 



In the great majority of cases the disease occurring in cacao has its 

 origin in the trees grown for shade. When these are cut out, aa often 

 becomes necessary as they get too large, the stumps are left to rot and 

 a condition is produced comparable in essentials with that in the clear- 

 ings just discussed. The danger is well known to planters, especially 

 with regard to breadfruit and avocado pear trees. A Grenada planter of 

 long experience claimed th it on several occasions whea root disease 

 had appeared in his cacao he had been able to trace it to the decay of 

 breadfruit roots cut through in digging drains. I have seen the fungus 

 on stumps of cacao trees which were healthy when cut down in thinning 

 operations. 



Apart from this, trees ot the kinds named are rather liable to die 

 of .their own accord. How often this is due to their contracting 

 Rosellinia disease, and how often they become infested with that fungus 

 only after the death of some or all the roots from other causes, I can 

 form no opinion. When, as often happens, the stumps are those of 

 healthy trees, cut down for other reasons, obviously the latter is the 



