66 TEINIDAD AND TOBAGO BULLETIN. [XVIIL 2.. 



think that this should be regarded as the minimum for even the best. 

 It is not suflficient to consider whether such treatment is needed in 

 favourable years, but whether its regular adoption is worth while as an 

 insurance against unfavourable ones. 



EOTATION. 



43. Under less satisfactory circumstances of climate, soil, or soil 

 condition, and this will apply to most of the land now subject to blight, 

 it is necessary' to go further and clean up the land thoroughly by leaving 

 out a cane crop, bringing it back into cane b^^ either Spring or Autumn 

 planting according to convenience, in the year following that in which 

 it was reaped, and cultivating it meanwhile in some alternative crop. 

 From the point of viev/ of sanitation, from which the subject is at 

 present being considered, the best crop is the one that involves the 

 most cultivation, for which reason root crops are to be preferred. The 

 choice of rotation crops will be further discussed in another section, 



44. The frequenc3' of alternation is again a question of conditions, 

 and is involved with that of the duration of ratoon crops. The choice 

 is open among all the gradations between a practice of clearing up the 

 land at long intervals (which is clone at present, in an imperfect and 

 primitive fashion, by throwing out fields when they will no longer bear) 

 and one of interposing a rotation crop at the end of the longer or 

 shorter succession of ratoons which follows each replanting. 



PiATOoNiNG Periods. 



45. In some cases it may be found sufficient (again with thorough 

 preparation and manuring) merelj' to reduce the number of ratoon 

 crops, without rotation ; the extreme of this policy being the growing 

 of plant canes only. The last-named measure is worthy of consideration 

 where it is desired quickly to restoi-e a run-down soil. 



46. In judging the results of any of these measures there should be 

 taken into consideration, on the credit side, the value of the improvement 

 •in the soil, and that of the insxu'ance against blight secured. These 

 values increase step by step with the thoroughness of the policy adopted ; 

 in the system of growing only plant canes, for example, the protection 

 against blight is almost complete. 



The Choice of Planting Material, 



47. It is highly desirable that the material used in planting should 

 be free from contamination with root fungus, which means that it 

 certainly should not be taken from a field noticeably infested. If 

 cuttings are free from sprouted roots, and top plants have no fungus 

 actually between the leaf-sheaths (cane wax must not be mistaken for 

 fungus) thej' are presumably satisfactory in this respect. 



48. Some of the popular ideas on this subject of selecting cane plants 

 are based on mistaken analogies with selection applied to reproduction 

 by actual seed. It involves a biological fallacy to suppose that cuttings 

 from vigorous plant canes will give anything in the nature of aa 

 improved strain as compared with cuttings taken from the scrubbiest 

 ratoons, provided that both are of the same variety. What may perhaps 

 be obtained in this way is a better start for the young plants and a more 

 certain freedom from actual contamination with root fungus. But 



