190 TEINIDAD AND TOBAGO BULLETIN. [XVIII. 4. 



On the other hand, without trenching all round it cannot be assured 

 that all the roots are cut, and the smallest is capable of conducting the 

 fungus outward or inward, as the case may be. The best plan would 

 probably be to dig a trench some 2 feet wide well away from the stump, 

 remove all sections of roots, and fill it in again. 



In planting the trees, positions in close proximity to stumps should 

 as far as possible be avoided, and a good deal may be done in the way 

 of re-arranging the smaller logs so that they do not form too close a 

 shelter about the stem of the prospective tree. Beyond these measures 

 little, for the time being, can be done. If the theory that the sour 

 orange stock is more resistant than the lime is shown by the experi- 

 ments now in progress to be well founded, then it will be advisable to 

 plant such situations as experience has shown to favour particularly 

 root disease with limes budded on that stock. 



When the first few years have passed and the logs are more or less 

 rotted, it has been shown to be quite feasible to hasten very materially 

 the time of their disappearance by cutting or breaking them up so that 

 the^' can be easily handled. Merely to dispose of them better by 

 dragging them away from the stems of the trees is a considerable gain, 

 and in some cases it has been found possible to stack much of the 

 material, and even to make good use of it for fuel. The great con- 

 venience, quite apart from root disease, of having the ground clear, 

 should be an additional inducement to the planter to make every 

 possible effort to this end. 



A point to be always kept in mind is that wood which can dry out 

 from time to time, e.g. logs, stumps, or parts of them which are raised 

 above the soil and not shut in by weeds or overhanging branches, is in 

 little danger of harbouring the fungus. 



The same consideration applies to the soil. In damp and sheltered 

 clearings such as are favoured by the fungus, all that is possible should 

 be done to encourage the free circulation of air beneath the trees. Low 

 hanging branches which maintain a closely sheltered circle around the 

 base of the tree induce conditions which invite surface infection, and 

 should most certainly be cut away. Grass and weeds should be kept 

 short all the time, not merely in the crop season. 



It is highly desirable in infested clearings and especially in the 

 neighbourhood of infected spots, to go further and clear away the soil 

 ^and weeds about the base of the stems, completely baring the collars, 

 and liberally exposing the main roots so far as this may be done without 

 forming a saucer in which water will stand. The treatment of the 

 collar and the recesses between the roots with lime-sulphur solution to 

 keep the bark free from moss gives an added protection of consider- 

 able value. 



All these measures are summarized in the word ventilation, and 

 cannot be too strongly emphasized. The fungus cannot tolerate dry 

 conditions and it is for the planter to take every advontage he can of 

 this weakness. 



