MONTHLY NOTES ON GRUBS AND OTHER CANE PESTS. 37 
results were very rapid; the grubs dying in from one to four days. Even 
the dry white arsenic gave splendid results. As this chemical has a great 
affinity for humus and remains in the surface soil for years, it may prove 
best to apply it in the drill at the time of planting, or perhaps dust it 
around the young plants, so that the grubs will come in contact with it 
when they begin their depredations. 
INTRODUCTION OF PARASITES. 
That we may leave no stone unturned, I have continued investigation 
of the valuable parasites of white grubs in other sugar-growing countries. 
There are a number available, though it is problematical whether they 
would prove of value against our native insects. Anyway, it is worth 
trying, for if we can induce them to attack any of our numerous 
Searabeids (root-feeding grubs) the expenses of introducing the parasites 
will be well repaid. These valuable insects are doing excellent service in 
Hawai, Porto Rico, Mauritius, and other countries. 
It will be interesting to quote from a letter just received from D. 
D’Emmerez de Charmoy, entomologist of the latter country. He says: 
‘“‘There are several parasites of white grubs here. Apart from 
Dielis rufa, an indigenous species parasitic upon two of our melolonthid 
grubs, Rhizotrogus gravidus and Rhizotrogus pallens, the others have been 
introduced. 
‘‘T am sending you a copy of a bulletin on the introduction of T'yphia 
parallela, in which you shall find a detailed account of the introduction 
of this parasite, as well as a general description of the spread of its host, 
Phytalus smathi. 
‘‘The other principal pest of sugarcane is Oryctes tarandus, which 
has lately been the cause of considerable damage to canes in certain parts 
of the island; so much so that I went to Madagascar, in 1917, for the 
purpose of bringing over certain Scoliids, which I thought might prove 
parasitic upon Oryctes tarandus. The details of this introduction are set 
out in the report I am sending you. 
‘*Sinee the publication of this report, Scolia oryctophaga has been 
found in places where the insects had originally been liberated, so that 
I think the parasite to be definitely established. Its effect in checking 
the spread of Oryctes tarandus is now only a question of time. 
‘‘T am extremely interested in the work tndertaken in Queensland 
for the purpose of controlling cane grubs, and feel certain that your 
eftorts will result in complete success. 
‘‘Tt would be a real pleasure for me to help you in any way, should 
you require my services.”’ 
