SKCriON VIII.— FACTORS INFLUENCING BLIGHT PREVALENCE. 1 1 1 



ii<'lds on Hermitage and La Fortunee Estates, three of which were qui ,e 

 free from blight and the remaining seven attacked to a greater or less 

 (l"gree. The results of this analysis so far as they appear to be of any 

 si;,'nificance ai-e shown diagramatically in Figs. 28 and 29. The fields aie 

 arranged from left to right, approximately in order of the severity of the 

 damage. 



A was a black soil field on Hermitage Estate " one of the best 

 fields on the estate — gave 38J tons of cane per acre last year." 



B was one of the best fields on La Fortunee Estate alongside the 

 Oropuche Lagoon. 



C was the lower part of a field at La Fortunee Estate, which gave a 

 very good crop except for a patch at the top of a rise in the field {see E). 

 The soil was visibly darker and less heavy at the bottom of the field 

 wliere this sample was taken. 



D was a field on La Fortunee Estate when the soil was a rather 

 heavy clay and the plants were poor in condition and slightly blighted 

 during 1918. 



E was the top of the hill mentioned above {see C) where the soil was 

 heavier and the canes were distinctly blighted. 



F was a field of medium heavy red clay on Hermitage Estate where 

 the canes were distinctly blighted late in 1917 as second ra toons. 



G was a heavy soil field on Hermitage Estate where the canes were 

 badly damaged at the end of 1917. 



H was taken from two badly damaged spots in the " Government 

 i'ond " field in Hermitage Estate referred to above (see p. ) as an 

 outcrop of heavy clay soil in an otherwise good field. 



I was a field at La Fortunee Estate, in which the young plants 

 were severely damaged by froghoppers during the dry season of 1918. 

 In view of more recent experience this field should have been put 

 nearer to the "good" end of the scale. This is interesting when the 

 acidity of the soil is taken into consideration {see below). 



K was a very heavy red clay soil field on Hermitage Estate, in which 

 the canes were completely destroyed by froghoppers m 1917. The sub- 

 soil is a heavy sticky yellow clay. 



Fig. 28 shews the percentage of the three valuable constituents of 

 the soil, Calcium oxide, Carbon dioxide, and Nitrogen (indicating organic 

 matter) in these ten sanaples. 



Figr 28. 

 Fig. 2i< Diaf,'i<nn of xahiahle clieiiiical constituents in snil i.f ten fields aii;:ng\'<l 

 from left to right in ai)i)i<)\i:nate order of liability to hiiglit. 



