PROCEEDINGS OF THE SECOND ENTOMOLOGICAL MEETING 25 
of potash is low, in some soils of this type being merely a trace while 
the “ available” quantity of phosphoric acid is exceedingly high, more 
so than in any other soil in tea. Addition of potash to such a soil is not 
of great value, and it would seem that it is fixed, and rendered non- 
available almost as soonasitisadded. The problem before us, therefore, 
is to discover the factor or factors which bring about the fixation and 
liberation of potash and phosphoric acid in the soil, and future work 
is to be directed to this end. 
The soil, of course, does not act directly on Helopeltis, but must act 
indirectly through the bush. An inquiry was therefore instituted to 
ascertain whether any relation could be traced between the attack ot 
the pest and the composition of the leaf on the bush, which could be 
correlated with differences in the soil. Samples of leaf were taken from 
three estates at intervals of a fortnight throughout the same season 
and analysed. On one estate, Helopeltis, though serious in some years, 
did not appear that season. On the second estate the pest was serious, 
and became more so as the season progressed, but the area never reached 
a stage at which it failed to give leaf. On the third estate the bushes 
shut up entirely at the end of August. The results were exceedingly 
interesting. On the first estate the ratio of potash to phosphoric acid 
remained fairly constant throughout the season. On the second estate 
this ratio gradually increased, the rate of increase becoming greater as 
end of the season was approached. On the third estate the ratio increased 
still more rapidly, and in August this increase was so rapid that the 
curve became almost vertical. This experiment needs to be repeated, 
and the differences observed are rather the result of attack than the 
cause of it, but here again the ratio of potash to phosphoric acid is seen 
to have a bearing on the question. 
Experiments have also been tried, by injection of bushes with soluble 
mineral salts, and by keeping plucked shoots with the cut end of the stalk 
immersed in different solution, to see whether differences in hability to 
attack could be brought about. Differences have been observed, but 
the experiments have not yet been carried far enough for any definite 
statement to be made. 
In Southern India the case is entirely opposite. The larger quantity mr, Anstead. 
of soluble phosphate gives the best results. 
The ratio is the chief point. Mr. Andrews. 
I mean “‘ ratio” by the “ soluble phosphate ”. The composition of Mr. Anstead. 
the soil varies considerably in the Planting Districts in Southern India. 
Consequently soil surveys are the first necessity. For want of exact 
information on this point, several manurial experiments are vitiated. 
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