iSECTIONVIII. — FACTORS INFLUHNCIXa BLKMET PIIKVA LKXCK. 11!) 



juanure is required to impi'ove the soil conditions of the poor soils and 

 clays, and the larojer the extent to wliich animals are nsed tlie more of 

 tliis will be available. 



There is scarcely any operation that cannot be performed by 

 .uiimals. Light ploughs pulled by mules can pass between the cano 

 vows and I have seen on the lands of the Usino See. .\radeleine a plough 

 with twenty-two oxen tearing up the old cane stools in heavy land. 

 Except where speed is required or very large areas have to be covered, 

 tliese methods could nearly always be adopted. 



DEPTH OF PLANTING. 



On several occasions it has been sugge?ted to me that the depth at 

 which the original cuttings are planted might influence the amount of 

 blight by producing a shallower or deeper root system moi^e or less 

 exposed to the sucking of the nymph. 



Moore in British Guiana (1919 p. 13) says "plant as deeply as possible, 

 -as with old ratoons when the stools get high out of the ground the i*oot 

 system is specially liable to attack — and so with shallow planting." 



I have at present no evidence that the depth of planting affects 

 either the depth of the root system or the amount of blight and as in 

 Trinidad the depth of planting is governed almost entirely by the time 

 of the year and the heaviness or depth of the soil it would be difficult 

 to alter it except within very small limits even if it were proved to have 

 an effect. 



DISTANCE OF PLANTING. 



There is at present no evidence that the distance that the canes are 

 ]ilanted in any way effects the blight. The Trinidad planter, faced 

 with a shortage of labour, has to choose between the reduction of 

 weeding by close planting and the facilities for rapid inter-row cultiva 

 tion in wide planting. 



VARIETY OF CANE. 



In 1919 (D.) I made a report on the relative resistance to blight 

 ■of the various varieties of cane grown in Trinidad, and came to the 

 -conclusion that no variety was immune, but that a few were more resistant 

 than others. 



During the past year no observations have been made which in any 

 way affect that statement. Some of the varieties that had not up to then 

 been attacked owing to their recent introduction and small distribution 

 have this year shown that thej' also are not immune. 



Thus the recently introduced B.A. 6032, a very valuable variety, has 

 this year been severely damaged by blight on one estate. 



A few observations of relative condition of different varieties in the 

 same field might be added to those already given {loc. cit. p. 82), 



Hills Seedling (No. 1.) was less damaged than B. 1753 at Union Hall. 



Uba was less damaged than Hill No. 12 at Golconda. 



Hills Seedling (No. 1) was less damaged than B. 156 at Hermitage. 



D. 109 was less damaged than D. 347 at Tarouba. 



D. 109 was less damaged than D. 347 at Harmony Hall. 



The two most resistant varieties at present known are Uba and 

 Badilla, both of which are said to be deep-rooted, but it is not known 

 whether this is the cause of the resistance or not. 



In 1918 a number of stools at St. Augustine were cut through 

 vertically to get an indication of the depth of the root system and the 

 Badilla was not noticeably deeper than the other varieties. 



