24 PROCEEDINGS OF THE SECOND ENTOMOLOGICAL MEETING 
time of the first application, and the spraying, wherever possible, is 
usually supplemented by plucking off all young shoots, care being taken 
to pluck those in the heart of the bush as well as on the plucking surface. 
Hand-catching by small boys is almost universal. 
A study of the distribution of this pest brings out several curious facts. 
It occurs, at its worst, 1m the Terai and Duars, and in those parts of 
Cachar, Sylhet and Assam which approximate to the hills, and where 
there is a liability to dull, rainy weather, with absence of sunshine and 
heavy rain for long intervals. This sort of weather is exceptionally 
favourable for the development of Helopeltis, and it has been found 
possible, by plotting curves based on the number of rainy days, and 
the amount of fall per day, to correlate conditions and intensity of 
attack. In the Duars there are two distinct types of soil. One is a 
erey loamy soil, the other a stiff red clay. It was noticed that most 
of the badly affected gardens were on the grey loam, gardens on the red 
clay being much less lable to attack in most cases. Examination of the 
analyses of typical samples of these soil types showed that the ratio of 
available potash to available phosphoric acid was high in the red clay 
soils and low in the grey loams. Samples from red clay soils which were 
becoming liable to attack were found to occupy an intermediate posi- 
tion. In Cachar Helopeltis attack is worst on the bheels, least on the 
red teelas and here, again, the same differences in the ratio were found 
to obtain. Experiments were therefore carried out. to ascertain whether, 
by increasing this ratio, the bushes in a soil could be rendered less liable 
to attack. The first experiment, carried out in a garden in Cachar, 
consisted in the application of sulphate of potash, and this gave excel- 
lent results, even though the potash was applied towards the end of the 
season. During the next season an extended series of experiments 
was drawn up, to be carried out on estates in the Duars and Cachar. 
Owing to the outbreak of War, the series could not be carried out in 
toto, but beneficial results were obtained, on both the red clay soils and 
on the grey loams, in certain cases. Last season further experiments 
were carried out, and it is significant that, on estates where results had 
been obtained before, similar results were again obtained. Thus evidence 
has been obtained to show that an addition of potash, in a readily soluble 
form, to a soil, will, under certain conditions, produce a decrease in the 
lability of the bushes growing in the soil to Helopeltis attack. One 
of the conditions necessary for this treatment to be effective appears to 
be a shortage of total potash in the soil. In the case of the grey loam of 
the Duars, however, we find that while the total amount of potash in 
the soil tends to be slightly on the high side, and the total amount of 
phosphoric acid tends to be on the lew side, the “ available ”’ quantity 
