40 MONTHLY NOTES ON GRUBS AND OTHER CANE PESTS. 
GREENHILLS ESTate. 
Entering the plantation on the north, everything appears most 
favourable for a good crop; but as soon as one passes the high ground 
at the centre of the estate a terrible scene of devastation opens up. It 
looks as if a severe drought had struck it, in many places the tops being 
entirely dry. Fortunately, this year there has been no severe winds, and 
very little of the cane has fallen. The roots of these drying stools are all 
eaten off, however, and it is an easy matter to pull them over with one 
hand, for the soil is exceedingly friable. 
A bird’s-eye view of the estate under these conditions is most 
instructive, for it shows, decidedly, what I have been trying to emphasise 
in recent reports, that infestation has a very definite relation to the pre- 
vailing winds and feeding-trees. The part of the field adjoining the 
feeding-trees, to windward, is often less injured than that of the higher 
ground further back, as I have noted above. Evidently the beetles, in 
their blundering flight, follow the lnes of least resistance, and come to 
rest on any elevated area. At any rate, it is common experience that 
the high ground is most severely affected; it is always in these parts 
that the injury first appears, possibly because the soil is more leached 
out and poorer. 
It was most distressing to observe soon after I sent in last report, 
and before the refreshing rains, that the splendid cane of F3 was about 
to succumb. It will be recalled that part of this field was treated with 
a green crop of Mauritius beans, the effect of which was most remarkable 
upon the cane. The grubs were very noticeable in the untreated part 
of this field a month ago, but the cane of the treated portion continued 
a healthy green and had every appearance that it was going to resist 
the attack. The dry weather continued too long, however, and this 
beautiful field went brown in a week. Evidently the extra humus of the 
beans was not enough to carry the grubs over the trying period. With 
abundant, normal rainfall, however, the cane would doubtless have come 
through in good shape. Anyway, the added humus staved off the injury 
for more than three weeks, thus showing that this is a step in the right 
direction. 
A second disappointment has been the field C3 treated with sulphate 
of ammonia. Like the beans, this chemical showed a marked stimulus 
to the crop, and at the time of writing last report I had great hopes for 
a successful result. The lack of rain, however, proved too trying, and 
the cane finally went yellow. 
Arsenic at the rate of 10 lb. per acre sprayed or dusted on the 
vegetation at the time of ploughing the ground preparatory to planting, 
is proved to be of little or no value in destroying the grubs. All of the 
plots treated in this way have succumbed. It may be necessary to use 
more of the poison, but before we draw any conclusions we must await 
the results of other experiments. Those we have under way indicate 
that the poison has considerably more effect when applied near the roots 
of the young plants. 
