MONTHLY NOTES ON GRUBS AND OTHER CANE PESTS. 29 
- Figures such as these are suggestive of what might take place if an 
insect meets with particularly favourable conditions for development. 
Probably the most important of these are: (1) favourable climates; (2) 
abundant food; and (3) freedom from enemies. 
Nature is usually. nicely balanced, so that no species becomes 
predominent. Man, however, is often the means of upsetting this balance 
_ by transferring insects to new countries, where, removed from their 
natural enemies, they often become serious pests; or, again, by cutting 
the forest, he interferes with the nesting of insectivorous birds, &e., with 
the result that his crops are destroyed until Nature is again able to 
maintain her balance. 
It is now well recognised that man is able to greatly assist Nature 
in regaining this equilibrium; and much has been done by the intro- 
duction of insect parasites. It is possible, however, to do just as important 
work by encouraging the birds through protection, &., so that they will 
multiply near our homes. 
CULTIVATION EXPERIMENTS. 
I have started an extensive series of cultivation experiments, with 
proper checks, at the Greenhills Estate, on fields which are regularly 
destroyed by the grubs. These experiments cover both plant and ratoon 
crops, and we ean hope for some very interesting results within a few 
months, for the cane is an excellent stand at present. 
Three types of implements are being used, harrow, Planet Junior, 
and plough, and I am also trying different intervals to determine how 
often it is necessary to stir the ground and disturb the beetles. 
The cane in the Meringa plots is a perfect stand; and, though it 
was planted in April, it got such a setback by the drought that I am 
still able to keep the horse going through it. I am hoping for results of 
this intensive cultivation within the next two or three months. 
Noctuiw Moru-Borer, PHRAGMATIPHILA TRUNCATA, Walk. 
Mr. P. H. Edington, at Deeral, has suffered considerably from this 
pest. The insects have continued for several months on his plant cane; 
and he told me that he had renewed fully 75 per cent. of the plants in the 
worst-affected field. At the present time the cane is almost free from 
attack, and as high as one’s head, but very uneven, due to the fact that 
it has been supplied ‘at various times. 
~ [T was not able to locate any of the parasites, though at the time of 
my visit it was a very difficult matter to even find a caterpillar of the 
moth in the infested stalks ; most of the runs of the borer had been cleared 
out by the brown ant, Pheidole megacephala. 
