22 MONTHLY NOTES ON GRUBS AND OTHER CANE PESTS. 
if not eut out. I would strongly urge every one to assist in destroying 
this weed, if found on his premises, now that nature is arresting its 
spread. 
CANE GRUB INVESTIGATION, NOVEMBER, 1918. 
The extended drought is having a serious effect upon the cane in the 
Cairns district. Most of the late planting is barely holding its own, 
while cane planted early in the season is showing serious drying of the 
lower leaves. 
In some eases, where the fields were all prepared, planting has been 
so long delayed by the dry weather that the plants will not be put in this 
season. This has a rather serious aspect with regard to our investigation, 
for I was anxious to get the results from a number of these late-planted 
areas. However, we may be able to get results from what is already 
planted if the weather becomes favourable for growth and continued 
cultivation. 
CULTIVATION AS A ConTROL MEASURE FOR GRUBS. 
As has been demonstrated, cultivation during the period that the 
beetles are active seriously interferes with the laying of their eggs. 
Hence, the value of late planting, which permits thorough cultivation 
right through their ovipositing period. 
Let me urge, then, that the cultivators be kept active in every 
infested field, wherever it is possible to get through the cane. It is 
important to do this work even though the ground is clean, and it should 
begin not later than two weeks after the first beetles emerge. It will be 
well to go over the ground at least every two weeks as long as the beetles 
are in evidence. 
As indicated in my previous report, it may be profitable to start the 
preparation of the land which is to be planted early (April-May). The 
ploughing, harrowing, and so forth, will undoubtedly have a deterrent 
effect upon egg-laying in these new fields. Beetles do not like freshly 
Dloughed ground, especially if it is devoid of grass and trash. Definite 
observations by growers on these points will be appreciated, for they 
may save us a lot of detailed experiment. 
EXCHANGE OF PARASITES. 
Since the breeding of our parasitic wasps belonging to the genus 
Campsomeris, was so successful under artificial conditions, it has occurred 
to me that these insects might be very valuable if liberated in countries 
where they were free from their natural enemies. These foes are so 
abundant here that the wasps are scarcely able to make themselves felt 
in the open, though they breed very prolifically. Vast numbers of their 
young are destroyed by secondary parasites, and the adults that do 
escape probably often fall a prey to the numerous fly-catchers which 
are present here. 
