MONTHLY NOTES ON GRUBS AND OTHER CANE PESTS. 23 



"During the past month attention has been given to the rearing of 

 parasites, in order to obtain scientific data with regard to their life-history 

 and economy and to determine the best method of breeding extensively 

 and handling them in large numbers. 



"This branch of research work has been very successful, and in the 

 event of parasitic insects being introduced into Queensland from other 

 countries in the near future to cope with our cane grubs we are now in 

 a position to make the best use of such material. 



"The following brief account of the mode of wasp propagation 

 practised at Meringa may be of interest to growers : — 



"Digger parasites were confined separately in metal cages holding 

 about 15 cubic inches of soil, the grubs with attached eggs being removed 

 morning and evening and placed into cells formed in moist, compacted 

 earth that had been previously pressed into shallow wooden trays. A 

 convenient size of tray was found to be IG by 13 inches, which allowed 

 room for sixty cells, and when full they were stacked up so that the 

 bottom of each tray acted as a roof for that below, and left just enough 

 space to allow the larva? to spin their cocoons. At the present time (12th 

 April) about 750 specimens of egg, larval, and pupal stages of our two 

 principal digger-wasps may be seen at jNIeriuga Experiment Station. 



"We wish to emphasise the fact that the cane-grubs victimised by 

 both Campsomcris radula and tasmanicnsis are chiefly those of the 

 notorious grey-back beetle. Additional hosts affected by these parasites 

 include Anoplognathvs hoisduvalli, Lepidiota frenchi, rothei, and 

 caudafa. 



"The hundreds of grubs victimised at the Insectary during this 

 month (March) are third-stage alhohirta. 



Grubs under Blady Grass. 

 "Recent data obtained in the field at Meringa indicate that third- 

 stage larva? of Lepidiota frenchi are still feeding in virgin soil overgrovm 

 with blady grass and other cereals. Grubs collected hastily from 120 

 chains of plough-furrows, 4 to 6 inches deep, on clay loam land of the 

 above nature, yielded 107 specimens of third-stage alhohirta, 128 of the 

 same stage frenchi, and a few larvae of L. rothei and other scarabfeids 

 of minor importance. The grubs of frenchi as a whole are still feeding, 

 but will shortly travel deeper into the ground and form pupal chambers. 

 It is interesting to note that these grubs were derived from eggs deposited 

 in December, 1916, and have therefore been more or less injurious 

 during the past sixteen months." 



CANE GRUB INVESTIGATION, MAY, 1918. 



Attention must again be called to the value of cultural methods 

 as a factor in the control of cane grubs, at the same time correcting 



